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Zoologische Mededelingen, 86 (December 2012)

Review of the Philippine taxa formerly assigned to the genus Amphicnemis Selys. Part I: Overview and descriptions of three new genera (Odonata: Coenagrionidae)

R.J.T. Villanueva

Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands

D3C Gahol Apartment, Lopez Jaena St., Davao City, 8000, Philippines, rjtvillanueva@gmail.com

Keywords: Teinobasini;Pandanobasis;Sangabasis;Luzonobasis;Pericnemis;taxonomy;new species;

Abstract


The Philippine species formerly assigned to the genus Amphicnemis Selys are reviewed. Three new genera Luzonobasis gen. nov., Pandanobasis gen. nov. and Sangabasis gen. nov. are erected. Amphicnemis isabela is synonymised with Amphicnemis glauca and transferred to Luzonobasis gen. nov. Amphicnemis cantuga and A. mcgregori are transferred to Pandanobasis gen. nov. Amphicnemis braulitae, A. circularis, A. dentifer and A. furcata are transferred to Sangabasis gen. nov. The rest of the Philippine Amphicnemis species are transferred to the genus Pericnemis Hagen. Two new species are described: Pandanobasis curacha spec. nov. and P. daku spec. nov.

Introduction


The present higher order phylogenetic analysis of the family Coenagrionidae is still faced with ambiguity (Rehn 2003; O’Grady & May 2003; Carle et al. 2008). The traditional approach based on using wing venation is uninformative in addressing groupings within the family (Rehn 2003). However, a unique set of character states may be used safely to identify monophyletic groups (De Marmels 2007). Von Ellenrieder (2008) suggested the need of unambiguously defined genera for meaningful phylogenetic analysis of their relationships. Presently some genera are loosely defined. These include the genus Amphicnemis Selys, 1863, to which several Philippine species have been assigned, based only on details of wing venation.

The family Coenagrionidae occurs in a wide range of habitats from pristine forest to urban open drains. The strong tolerance of some species to pollution and habitat disturbance makes the group so widely distributed that it forms the main damselfly fauna on some of the islands in the Philippines.

In the Philippines, a total of fourteen coenagrionid genera are known (Hämäläinen & Müller 1997). Members of the family represent nearly 40% of the archipelago’s zygopteran fauna. The species presently assigned to the genera Amphicnemis and Teinobasis Kirby, 1890 make up a great majority of them. The genus Amphicnemis, in the present broad sense, is speciose with nearly 30 described species (Bridges 1994; Tsuda 2000; van Tol 2008; Dow et al. 2010). From the Philippines, twelve species have been described so far (see Hämäläinen & Müller 1997; Villanueva 2005; Gapud 2006), with several new species waiting to be described. Hämäläinen & Müller (1997) considered the Philippine Amphicnemis species to fall into three groups: the furcata-group, cantuga-group and lestoides-group, with only A. glauca falling outside of these groups.

The present paper deals with Philippine species that have been assigned to Amphicnemis sensu lato (s.l.). Three new genera are erected: Luzonobasis gen. nov. to accommodate Amphicnemis glauca; Sangabasis gen. nov. to accommodate the furcata-group; Pandanobasis gen. nov. to accommodate the cantuga-group. The rest of the Philippine Amphicnemis s.l. are transferred to Pericnemis Hagen in Selys, 1863; the genus in which some of them were originally described. Generic characterizations and diagnoses, and a key to the genera are given here. Descriptions of new species of Pandanobasis gen. nov. are also provided; the larger genera Sangabasis gen. nov. (Villanueva & Dow in preparation) and Pericnemis (Villanueva & Dow in preparation) will be dealt with in separate publications.

Material and Methods


This paper is based primarily on the material available at the Naturalis Biodiversity Center, formerly National Museum of Natural History, in Leiden, The Netherlands (RMNH), and in the author’s personal collection (RJTV). A great quantity of the Philippine specimens in the museum’s collections belongs to the material collected or acquired by Roland A. Müller from different islands of the Philippine archipelago in 1985-1997. Müller’s collection includes over 620 Amphicnemis s.l. specimens, which were preliminarily identified by M. Hämäläinen. A smaller number of specimens identified by M.A. Lieftinck were collected by himself, some US expeditions in 1950s and by the Noona Dan Expedition in 1961-1962. The Philippine Amphicnemis s.l. specimens from Senckenberg Museum Frankfurt (SMF), collected by G. Boettcher in 1913-1918, and Amphicnemis s.l. specimens from V.P. Gapud collection in the University of the Philippines-Los Banos (UPLB), were also studied. Primary types of species described by Needham & Gyger (1939) were not examined. Instead I have relied on the published descriptions and on the specimens at RMNH and SMF, identified by M.A. Lieftinck and M. Hämäläinen.

The male ligula and other structural features of some representative species were studied by scanning electron microscopy (SEM). Illustrations were made either from SEM images or with the aid of a Leica MZ16A microscope equipped with a Leica DFC500 camera. Terminology generally follows Watson & O’Farrell (1991). Maps were made using ArcView GIS 3.3. Measurements refer to holotypes; however, when a series of specimens shows more than 2 mm variation this is listed.

Brief taxonomic history


Selys (1863) established the genus Amphicnemis, which was divided into two parts: subgenus Pericnemis Hagen with a single species P. stictica Hagen from Java, and subgenus Amphicnemis Selys with a single species A. wallacii Selys from Sarawak, Borneo. The subgenera were separated as follows:

 


-

Amphicnemis “Secteur nodal naissant á mi-chemin environ du nodus au ptérostigma, qui occupe le dessus d’une cellule, et a son côté inférieur plus long que le marginal; le sous-nodal partant du nodus ou un peu après. Ailes assez étroites, pétiolées jusqu’á la naissance du quadrilatère au delá de la nervule basale postcostale, qui est située plus près du niveau de la seconde antécubitale que de la premiére. Secteur inférieur du triangle aboutissant environs aux deux tiers de l’aile, presque sous l’origine du secteur nodal…”

-

Pericnemis “Secteur sous-nodal naissant de la veine du nodus, le médian un peu avant. Ptérostigma irrégulier, carré en dedans, echancré au dehors, á côté supérieur moitié plus court que l’inférieur, suivi de deux rangs de cellules. Quadrilatère trés-lang a côté supérieur moitié plus court que l’inférieur...”


Selys (1863) originally included the genus Amphicnemis (including Pericnemis and Amphicnemis) within his Legion Platycnemis (present Platycnemididae) together with three other genera: Hypocnemis Hagen (= Risiocnemis Cowley), Platycnemis Charpentier and Chlorocnemis Selys. Later Selys (1877) transferred Amphicnemis and Pericnemis as subgenera to the genus Telebasis [Selys, 1877] in his Legion Agrion (present Coenagrionidae). However, Telebasis Selys, 1877 was a homonym of Telebasis Selys, 1865, and was renamed as Teinobasis by Kirby (1890). Other subgenera in the Selysian genus ‘Telebasis’ were: Leptobasis Selys, Stenobasis Selys, and ‘Telebasis’. Kirby (1890) ranked these taxa as full genera and he replaced the preoccupied name Stenobasis with the new name Archibasis.

Meanwhile Brauer (1868) had described three new species of Amphicnemis from the Philippines: A. glauca (based on the female only), A. lestoides, and A. furcata. Selys (1877) transferred Amphicnemis glauca to the subgenus Telebasis (= Teinobasis, see above), although he noted that it closely resembles A. lestoides, and retained Amphicnemis furcata and A. lestoides under Amphicnemis. He provided a preliminary grouping within Amphicnemis placing A. wallacii and A. furcata in one group: “Secteur médian naissant de la veine du nodus ou un peu plus loin, le sous-nodal encore un peu plus loin. Appendices supérieurs du male portant une forte dent basale interne. (Taille petite)”, and A. lestoides in another: “Secteur sous-nodal naissant de la veine du nodus, le médian un peu auparavant. Appendices superieurs du male simples. (Taille grande)”.

Selys (1889) described Amphicnemis ecornuta from Sumatra and ranked it as close relative of A. wallacii. Several new Amphicnemis species and one Pericnemis species were later described by Martin (1897), Krüger (1898), Ris (1911), Laidlaw (1912, 1913, 1926, 1931), and Lieftinck (1937, 1940, 1953) from Sundaland; for the synopsis see Lieftinck (1954). Recently Dow et al. (2010) added two species.

After the Selysian era the relationships of the Philippine Amphicnemis taxa were discussed in more detail by Needham & Gyger (1939). These authors commented briefly on Amphicnemis furcata, of which they had not seen any specimens, as follows: “A definitive generic allocation must await new and adequate material for study”. They transferred Telebasis (Amphicnemis) glauca, a species that Kirby (1890) had meanwhile included in the genus Teinobasis Kirby, 1890, to Pericnemis, although they wrote “This species we have not seen”. Needham & Gyger (1939) described five additional new species from the Philippines within the genus Pericnemis: P. bonita, P. cantuga, P. incallida, P. flavicornis, and P. mcgregori. Discussing the characters of the genus as regards to the new species they noted: “This material permits a fuller characterization of the genus [Pericnemis] that has been possible hitherto. Of the generic character stated by de Sélys the two emphasized as most distinctive, the 5-sided stigma and the double row of cell following it in the apical costal space, now are seen to hold only for the type species, P. stictica Sélys.” They also provided an emended diagnosis of the genus Pericnemis.

Lieftinck (1940), who treated the Sundaland Amphicnemis species in detail, suggested in a short footnote (p. 362) that the Philippine species described by Needham & Gyger as Pericnemis should be transferred to Amphicnemis. Lieftinck wrote: “Recently, Needham and Gyger [...] have transferred A. glauca and A. lestoides to the genus Pericnemis, leaving only furcata in Amphicnemis. From a study of the types of these species I find that they are true Amphicnemis, as are also the five new species of Pericnemis, reported by Needham and Gyger from these islands. Lastly, Teinobasis dentifer Needham & Gyger, of which I have examined both sexes should, I think, also be transferred to Amphicnemis”. Later, Lieftinck (1957) discussed and redescribed four Philippine Amphicnemis species (lestoides, bonita, glauca and furcata) based on specimens in IRSN (Brussels), SMF or collected by himself in Luzon; illustrations were provided for glauca, lestoides and furcata. However, in neither of these papers did Lieftinck give any reason for removing the Philippine taxa from Pericnemis to Amphicnemis. Lieftinck (1974) described a new species Amphicnemis circularis from Tawi Tawi and discussed its close relation with A. furcata. He also wrote: “A second species, unquestionably also a true Amphicnemis, but probably more remotely allied, is Teinobasis dentifer.”

Following Lieftinck’s decisions, in subsequent papers on the Philippine odonates, and in all world catalogues of Odonata, these damselflies have been placed in Amphicnemis. Hämäläinen & Müller (1997) listed 25 ‘species entries’ (including taxa marked as ‘sp.n.’, ‘sp.’ or ‘sp./spp.’) for the Philippine Amphicnemis s.l., placing the taxa in three groups based on the structure of the male appendages. Later, Villanueva (2005) and Gapud (2006) described a new Amphicnemis s.l. species from the Philippines.

Taxonomic overview


Subfamily Teinobasinae Tillyard, 1917

De Marmels (2007) treated Teinobasinae as subfamily of Coenagrionidae and established a new genus Tepuibasis. He recognised two subsets within the subfamily, those with a ventro-basal spur on the cerci of the male represented a ‘Tribus Teinobasini’ (De Marmels 2007; Fraser 1957), and those that lack that structure are considered a paraphyletic group numbering ten genera, no formal tribe name was proposed. Presently, ten genera are recognized in the tribus Teinobasini (sensu De Marmels 2007), although De Marmels noted that he was not able to examine some additional genera in the Old World.

Study of the Old World members finds the group to possess an angulate frons (e.g., fig. 3). This character is variable in Neotropical genera. Presently, six genera belonging to Teinobasini are recognized in the Old World: Amphicnemis, Melanesobasis Donnelly 1984 , Papuagrion Ris 1913, Pericnemis, Plagulibasis Lieftinck 1949, and Teinobasis, all having an angulate frons and a ventro-basal spur on the male cerci. In this publication the main branch of the cerci is referred to as the upper branch and the ventro-basal spur as the lower branch. The present study on Philippine species formerly assigned to the genus Amphicnemis raises the known number of genera under the tribe to nine in the Old World.

This study found that the preliminary grouping of Philippine Amphicnemis s.l. presented in Hämäläinen & Müller (1997) is basically sound. The taxa were placed quite conveniently in three species-groups (cantuga-group, furcata-group and lestoides-group) except for A. glauca whose taxonomic placement was left open due to the absence of any male specimen for study at that time. Discovery of the male of A. glauca has revealed that the species is so distinct that it deserves to be grouped separately.

Key to the Old World Teinobasini (males only)


1.

Femoral and tibial spines as long as or longer than the space between them

2

-

Femoral and tibial spines clearly shorter than the space between them

4

2.

Tarsal claws without denticle

Plagulibasis Lieftinck, 1949

-

Tarsal claws with distinct denticle

3

3.

Cerci clearly longer than abdominal segment 10 (S10) and paraprocts shorter than cerci (figs 18-21)

Pandanobasis gen. nov.

-

Cerci at most as long as S10 and paraprocts distinctly longer than cerci

Melanesobasis Donnelly, 1984

4.

A tubercle or ridge present in the distal portion of the base of ligula (figs 6-7)

5

-

No tubercle or ridge in the distal portion of the base ligula (e.g. fig. 5)

7

5.

Slender species; rudimentary lower branch of the cerci one-fifth or less the length of the upper branch (fig. 13)

Sangabasis gen. nov.

-

Large robust species; well-developed lower branch of the cerci two-third or longer than the length of the upper branch (figs 11-12)

6

6.

Epiproct very well developed, elongated and easily visible in both dorsal and lateral views (figs 10-11); posterior lobe of prothorax with a pair of rearward directed processes

Luzonobasis gen. nov.

-

Epiproct poorly developed, button-like and not visible in dorsal or lateral view; posterior lobe of prothorax simple or with only a single centrally placed horn

Pericnemis Hagen, 1863

7.

Large robust species; tarsal claw with distinct denticle, R4 arising before subnodus

Papuagrion Ris, 1913

-

Slender species; tarsal claw without denticle or at most a tiny rudimentary denticle, R4 arising at or a little distal from subnodus

8

8.

Cerci with the upper branch clearly longer than S10; paraprocts always shorter than cerci; IR3 and R4 originate well distal to subnodus

Amphicnemis Selys 1863

-

Cerci with the upper branch clearly shorter than S10; paraprocts well developed and sometimes longer than cerci; IR3 and R4 originate at or very close to the subnodus

Teinobasis Kirby 1890


The Philippine genera formerly placed in Amphicnemis


1) Amphicnemis glauca Brauer, 1868

This peculiar species was described under Amphicnemis based on a single female specimen taken somewhere in Luzon. It was later transferred to Telebasis (= Teinobasis), then to Pericnemis and later on back to Amphicnemis (Selys 1877; Needham & Gyger 1939; Lieftinck 1940). This species is here placed in a monotypic genus Luzonobasis gen. nov. So far it is known only from the island of Luzon; the genus is probably confined to the Philippines.

Gapud (2006: 36) described Amphicnemis isabela from Palanan, Isabela, Luzon Island based on a single male specimen. Villanueva, van der Ploeg & van Weerd (2009), also collected two male and one female specimen in Palanan that resembled A. isabela. During this study I found Amphicnemis isabela to be identical with L. glauca, and it is here ranked as a junior synonym of L. glauca.

Luzonobasis glauca seems to be the only currently known Philippine species with a bicoloured pterostigma. This character makes it quite easy to associate specimens from different localities although the species was originally described on the basis of a single female specimen. The stature of the species and the structure of its ligula suggest a close affinity with the Pericnemis lestoides-group. However the bicoloured pterostigma and the distinctly long epiproct place his group apart from the rest of known Philippine genera.

Luzonobasis gen. nov.

(figs 2, 8, 9, 10, 11, 22)

Type species.— Amphicnemis glauca Brauer, 1868 by present designation.

Etymology.— Combination of the name ‘Luzon’ (the largest Philippine Island) and the suffix ‘basis’ indicating its close relationship with other Teinobasini.

Description of the genus.— Large coenagrionid. Frons angulate in profile with postclypeus slightly broader than anterior portion of frons. The anterior portion of the head is generally pale or bluish except for the black postclypeus and basal portion of labrum. Posterior half of the head is generally black or dark metallic green. Postocular markings absent. The posterior lobe of the male prothorax is produced at rear into a pair of well-separated, very broad, triangular, flat processes (fig. 8). Synthorax mainly bluish green. Legs mainly pale except for short black femoral spines. Tarsal claws without denticle. Wings hyaline with dark brown veins; arculus (Arc) just distal to second antenodal (Ax2); anal crossing (Ac) near Ax2; petiolation ceases at the level of Arc; R4 just proximal to subnodus; IR3 just distal to subnodus; R3 at Px8 and Px7 (Px = postnodal) in forewings and hind wings respectively; IR2 at Px11 and Px10. Pterostigma (fig. 2) squarish: in forewing entirely black; in hind wing the basal and subcostal side yellow, costal and distal side including a circular off-centre patch dark brown. The abdomen is mainly black or dark greenish; pale ventrally. The cerci are branched and more than twice the length of S10. Epiproct remarkably elongate, very long, reaching a quarter length of the upper branch of the cerci. The base of the male genital ligula is equipped with a tubercle. Female S8 lacking vulvar spine; cerci shorter than S10; ovipositor surpassing the outer margin of S10.

Larva.— unknown.

Diagnosis.— This is the only known member of the Teinobasini with a very long epiproct (fig. 10) that is clearly visible in lateral view (fig. 11), nearly half the length of S10 (exposed portion). Among the Old World Teinobasini, it shares with Amphicnemis, Pandanobasis gen. nov., Pericnemis and Sangabasis gen. nov. the presence of long cerci in the male, typically 1.25 times longer than S10. However, the bicoloured pterostigma (fig. 2) is only shared with Amphicnemis sensu stricto (s.s.), from which it differs in general stature, structure of the male genital ligula and the long epiproct. The male genital ligula is similar to Pericnemis and Sangabasis gen. nov. in that it bears a tubercle on the distal portion of the base of ligula. It differs from Sangabasis gen. nov. by the well-developed lower branch of the cerci, while Pandanobasis gen. nov. has long femoral spines and a lower branch of the cerci with an expanded tip. It closely resembles Pericnemis, at least the lestoides-group, except for the very long epiproct, the paired process on the posterior lobe of pronotum of the male, and the bicoloured pterostigma.

The genus Luzonobasis gen. nov. is monotypic: Luzonobasis glauca (Selys, 1877) comb. nov. (type species).

Luzonobasis glauca (Brauer, 1868) comb. nov.

(figs 2, 8, 9, 10, 11, 22)
Amphicnemis glauca Brauer, 1868 (original description); Lieftinck, 1940; Lieftinck, 1957; Hämäläinen & Müller, 1997; Gapud, 2006.
Telebasis glauca (Brauer, 1868); Selys, 1877.
Pericnemis glauca (Brauer, 1868); Needham & Gyger, 1939.
Amphicnemis isabela Gapud, 2006; Villanueva, van der Ploeg & van Weerd, 2009 Syn. nov.
Material.— Philippines: 1 ♂ (RMNH), “Luzon Id, Aurora Prov., Dinalungan, Mt. Anaguao, Alebit River area, 600-900 m, 9-14.iii.1997. R.A. Müller”; 2♀♀ (RMNH), “Luzon Id, Aurora Prov., Dinalungan, Mt. Anaguao, Alebit River area, 600-900 m, 9-14.iii.1997. R.A. Müller”; 3 ♀♀ (RMNH), “Luzon Id, Apayao Prov., Flora, Santa Maria, Lumon River area, 300-500 m, 14-20.iv.1997. Celso Nazareno”; 1♀ (UPLB), “Isabela, Palanan, PLFDP-CI, Ditalad creek, 19.v.2004, VPG; 2 ♀♀ (UPLB), “Isabela, Palanan, PLFDP-CI, Ditalad creek, 4-5.vi.2002 VP Gapud; 1 ♂ (UPLB), “Isabela, Palanan, PLFDP-CI, Ditalad creek, 19.v.2004, VPG (type A. isabela); 1 ♂, 1 ♀ (RJTV), “Dipinantahikan area (16°53’39”N, 122°20’47”E), Dipagsangaan, Palanan, Isabela, Luzon Island, 12-20.ix.2008, RJTV”.

Diagnosis.— This species is easily identified by the dark brown pterostigma in forewing and yellow and brown pterostigma in the hindwing. The slender, tapering lower branch of the cerci and very long epiproct are diagnostic.

Description of male: (first description).— Labium whitish. Mandible bases beige. Labrum shiny black except for yellow anterior quarter, which is fringed with long fine dark brown setae. Genae beige. Anteclypeus bluish white except for black markings in the upper half centrally. Postclypeus black. Frons black with distinct ridge; anterior (vertical) portion with transverse sinuous yellow stripe, attenuated at the middle. Vertex black with metallic reflection except for whitish vertical streak at the anterior border of the antennae bases, antennae mostly brownish but scape black, white at top. Rest of head black except for short elongate pale streak between lateral ocelli and bases of antennae, a bluish spots posterior to lateral ocelli, and bluish hind margin of occiput forming a broad X-shaped mark.

Thorax.— Prothorax with anterior lobe of pronotum blue except for black anterior margin, short and erect. Propleuron and middle pronotal lobe simple, blue except for black midline that is broader posteriorly. Posterior pronotal lobe black with metallic green reflection: free margin produced into a pair of triangular, flat process, directed rearwards and upwards (fig. 8). Synthorax – Mesepisternum mostly metallic green. Mesepimeron mostly bluish. Metepisternum and metepimeron bluish. Legs – Coxae and trochanters whitish; femora and tibiae beige, black on the extensor surface of femurs, around the joint of femur and tibia and in a narrow streak on extensor surface of tibia. Femoral spines black, shorter than the space between them. Tarsal claws without denticle.

Wings.— As described for the genus, with 17 and 16 Px in forewing and hindwing respectively.

Abdomen.— S1 bluish except for black dorsal patch tapered basally. S2 dorsum black, laterally pale. S3-S7 dorsum brown becoming darker distally on each segment and with pale basal ring. S8-9 black, S8 with a pale streak laterally near tergal border. S10 black with pale apical-lateral streak. Cerci (figs 10-11) whitish, more than twice the length of S10. Upper branch smoothly arched (fig. 11), cylindrical in basal half, flattened and somewhat expanded in apical half, with a rounded tip, and slightly concave on inner surface. Lower branch slender and cylindrical, gently tapering and curved inwards and upwards to a pointed black tip, not reaching the level of the upper branch. Epiproct (fig. 10) very long, reaching a quarter length of the upper branch.

Measurements [mm].— Abdomen + cerci: 49; Hind wing (Hw): 30.

Description of female (re-description).— Similar to male except: labrum shiny black except anterior third yellow. Anterior portion of frons mostly yellow. Vertex black except for a pale vertical streak at the anterior margin on the bases of antennae, whitish base of antennae, antennae otherwise brownish; and a short, slender streak between antennae and lateral ocelli. The rest of the head is brownish orange except for a black streak from vertex extending to lateral side of hind margin of occiput. Thorax with posterior pronotal lobe (fig. 9) simple and collar-like, centrally a little broader than laterally and with free margin up turned here. Mesepisternum black in anterior half and brownish in posterior half; anterior part of metepimeron brownish-yellow; the rest of the synthorax bluish. S8 black, with more extensive pale marking compared to male. S9 whitish except for a black ventro-basal patch; S10 whitish.

Measurements [mm].— Abdomen + cerci: 44; Hw: 31.

Distribution and habitat.— This genus is known only from Luzon Island (central and northern Luzon). The present materials available were collected in primary forest. One male encountered in Palanan, Isabela Province was caught in the forest with no nearby water source, suggesting the possibility that this genus breeds in phytotelmata.

2) Amphicnemis cantuga-group

Amphicnemis cantuga was originally described as Pericnemis cantuga by Needham & Gyger (1939) on the basis of a single specimen, preserved in alcohol. Lieftinck (1940) transferred this species to Amphicnemis without giving reasons. However, Needham & Gyger (1939) had already noted the difference “the species is tentatively placed here (Pericnemis) for want of a better location, although it differs from the others described”.

Recent study of the Philippine Amphicnemis s.l. suggests that four species, including two described here, stand apart from the rest. Since the descriptions of A. cantuga and A. mcgregori, no new material of this species-group became available until Roland A. Müller started building his Philippine Odonata collection and obtained several specimens from various islands (Hämäläinen & Müller 1997). Specimens belonging to the two new species described here were preliminarily identified as A. cantuga by M. Hämäläinen, and consequently their range was included into that of A. cantuga in the synopsis of Philippine Odonata by Hämäläinen & Müller (1997).

The group differs from the other Philippine members previously assigned to Amphicnemis by the absence of a tubercle on the base of ligula. The apical section is modified into an elongate structure, nearly reaching the ‘middle’ of the base (fig. 5), a character not present in the rest of Philippine Amphicnemis s.l. The upper branch of the cerci is long and hook-shaped (similar to Sundaland Pericnemis) compared to curved or directed straight caudad in other Philippine Amphicnemis (now placed in Sangabasis gen. nov. and Philippine Pericnemis). The lower branch of the cerci has a slightly expanded and flattened tip, a character not present in any other Old World Teinobasini. The group is regarded to form a new genus Pandanobasis gen. nov., known only from the Philippines.

Pandanobasis gen. nov.

(figs 1, 5, 14, 15, 16, 17, 18, 19, 20, 21, 23)

Type species.— Pericnemis cantuga Needham & Gyger, 1939 by present designation.

Etymology.— Combination of ‘Pandan’, the name of the plant genus name Pandanus in the local Cebuano dialect of the Philippines, and the suffix ‘basis’ indicating its close relationship with other Teinobasini. Pandanus forests are the typical habitat of its members.

Description of the genus.— Large and robust coenagrionids. Profile of frons angulate, with anterior portion broader or similar width to postclypeus. Labrum largely bluish or yellowish. Anterior half of head generally yellowish, posterior half generally black or bronzy green. Post-ocular markings absent. Synthorax generally greenish-blue except for yellowish mesinfraepisternum, mesepisternum and the anterior portion of mesepimeron. The legs are long and entirely yellow including spines. Femoral and tibial spines as long as, or longer than, the intervening spaces. Wing broad, hyaline with black veins; Arc at or distal to Ax2; Ac nearer to Ax2 than Ax1; petiolation ceases at Ac or just a little distal to it; R4 more than a quarter cell length proximal to subnodus; IR3 at subnodus. Pterostigma rectangular, costal side a little shorter than subcostal side. Abdomen blackish or brownish, pale ventrally. Cerci (figs 14-17, 18-21) pale yellowish, in lateral view longer than S10. The upper branch is hook-shaped; lower branch elongate, a little shorter than the upper branch, with a slightly expanded concave tip with black medial internal tooth. Paraprocts with broad base and a short tubercle. Male genital ligula has a flattened and elongate apical section reaching nearly the ‘middle’ of its base in normal resting position (fig. 5). Female S8 lacking vulvar spine; cerci shorter than S10; ovipositor just reaching outer margin of S10.

Larva.— unknown

Diagnosis.— Pandanobasis gen. nov. is clearly distinguished from other Philippine Teinobasini by the form of the anal appendages and genital ligula. Luzonobasis gen. nov., Sangabasis gen. nov. and Pericnemis possess a distinct ridge or tubercle on the distal portion of the base of the ligula, this character is absent in Pandanobasis gen. nov. and the rest of the Old World genera of Teinobasini studied and New World coenagrionid genera (Garrison, personal communication). The ligula of Amphicnemis and other Teinobasini has a well-developed terminal fold of the apical section and a broader and open ‘middle’ section, while Pandanobasis gen. nov. has a rounded ‘middle’ section. In Pandanobasis gen. nov., the apical section of ligula is flattened, elongated, curved and tapered reaching nearly the ‘middle’ of the base in normal resting position (fig. 5). The upper branch of the cerci is long (longer than S10) and hook-shaped. The lower branch is robust, nearly reaching the upper branch, with a slightly expanded concave tip with a medial tooth. Among the Old World Teinobasini, the long cerci (longer than S10) are shared by Amphicnemis, Luzonobasis gen. nov., Pandanobasis gen. nov., Pericnemis and Sangabasis gen. nov.

Pandanobasis gen. nov. differs further from some other member of Old World Teinobasini by having long femoral and tibial spines, which are of similar colour to the rest of the leg. This character (long femoral and tibial spines) is shared only with the genus Melanesobasis (Donnelly 1984) and Plagulibasis (Lieftinck 1949).

The position of vein R4 in Pandanobasis gen. nov. is well proximal to the subnodus, as in Melanesobasis, Papuagrion and some Pericnemis species (sticta-group and incallida-group). Teinobasis and Sangabasis gen. nov. have R4 originating at subnodus or very close to it, while Amphicnemis has a more distal origin. Pandanobasis gen. nov. (as well as Melanesobasis, Papuagrion and a few Pericnemis species) have shallow head; thicker synthorax, and tarsal claws with distinct denticle. Amphicnemis, Sangabasis gen. nov. and Teinobasis contain slender species, mostly with prominently bulging compound eyes. Pandanobasis gen. nov. is close to Papuagrion and some Pericnemis in relation to general stature, venation, and the presence of a denticle on the tarsal claws.

The genus Pandanobasis gen. nov. currently includes four species, two of which are new to science: Pandanobasis cantuga (Needham & Gyger, 1939) comb. nov. (type species); Pandanobasis mcgregori (Needham & Gyger, 1939) comb. nov.; Pandanobasis curacha spec. nov. ; Pandanobasis daku spec. nov.

Key to males of Pandanobasis gen. nov.


1.

Lower branch of cerci robust, about half the width of upper branch

2

-

Lower branch of the cerci slender, about a third the width of upper branch

3

2.

Tip of the upper branch of cerci with large interior tooth; paraprocts elongated and projected (fig. 21)

P. daku spec. nov.

-

Tip of the upper branch of cerci with minute interior tooth; paraprocts broad and not projected (fig. 18)

P. cantuga (Needham & Gyger, 1939)

3.

Tubercle of paraprocts directed toward the margin of S10 (fig. 20), or pressed against it; labrum yellow

P. curacha spec. nov.

-

Tubercle of paraprocts directed slightly away from the margin of S10 (fig. 19); labrum bluish

P. mcgregori (Needham & Gyger, 1939)


Pandanobasis cantuga (Needham & Gyger, 1939) comb. nov.

(figs 1, 5, 14, 18, 23)
Pericnemis cantuga Needham & Gyger, 1939 (original description).
Amphicnemis cantuga (Needham & Gyger, 1939); Lieftinck, 1940 ; Hämäläinen & Müller, 1997 (part; populations in Mindanao and Dinagat); Villanueva, 2009.
Material (all in RMNH unless otherwise stated).— Philippines: 1 ♂, 1 ♀, “Dinagat Id, Surigao del Norte, Mt. Canbinlio, ii.1989, Alex Buenafe”; 1 ♂, “Dinagat Id, Mt. Canbinlio, Balitbiton River, ix.1989, Alex Buenafe”; 2 ♂♂, “Dinagat Id, Surigao del Norte Prov., Loreto, Balitbiton, Mt. Canbinlio, vii.1989, Alex Buenafe”; 1 ♀, “Mindanao Id, Davao Oriental, Boston, Caatijan, 500-550 m, 28.v.1996, Müller/Buenafe/Gorostiza”; 1 ♂, “Mindanao Id, North Cotabato, Mt. Apo, Lake Agko, 1200-1300 m, 29.iii-2.iv.1995, Roland A. Müller”; 1 ♀, “Mindanao Id, North Cotabato, Mt. Apo, Lake Mainit, 1450 m, 2.iv.1995, Alex Buenafe”; 1 ♀, “Mindanao Id, North Cotabato, Mt. Apo, Sirawan creek, 900-1200 m, 12-25.ix.1994, Alex Buenafe”; 1 ♀, “Mindanao Id, North Cotabato, Mt. Apo, Marbel River, 1200-1300 m, 2.iv.1995, Alex Buenafe”; 5 ♂♂, 1 ♀, “Mindanao Id, North Cotabato, Alamada, Mt. Makatoring, 700-900 m, 1-8.ii.1992, T. Borromeo “; 1 ♂, “Mindanao Id, Davao Prov., east slope Mt. McKinley, 6.ix.1946, F.G. Werner”; 1 ♀, “Mindanao Id, Davao Prov., east slope Mt. McKinley, 13.ix.1946, H. Hoogstraal”; 1 ♂ (SMF), “Dinagat, 15.xii.1915, G. Boettcher”; 1 ♀ (SMF), “Surigao, Mindanao, 7.viii.1916, G. Boettcher”; 1 ♂ (RJTV), “Marahan, Davao City, Mindanao Is, 20.v.2009, RJTV”; 1 ♂ (RJTV), “Amindangan river, La Union, San Isidro, Davao Oriental, Mindanao Is, 8.iv.2009, H.Cahilog”; 1 ♂ (RJTV), “Tagbina, Surigao del Sur, Mindanao Is, 23.v.2009, RJTV”; 1 ♂ (RJTV), “Danao Daku, Ferdinand, Loreto, Dinagat Is, 26.viii.2008, RJTV”; 2 ♂♂ (RJTV), “Danao Gamay, San Juan, Loreto, Dinagat Is, 8.vi.2008, RJTV”. 3 ♂♂, 1 ♀ (RJTV), “Butac, La Union, San Isidro, Davao Oriental, Mindanao Is, 28.viii.2009, H. Cahilog”; 5 ♂♂ (RJTV), “Amindangan River, La Union, San Isidro, Davao Oriental, Mindanao Id., 29.v.2009, HC”; 3 ♂♂ 1 ♀ (RJTV), “Butac, La Union, San Isidro, Davao Oriental, Mindanao Id., 28.vi.2009, HC”; 1 ♂ (RJTV), “Aragon, Cateel, Davao Oriental, Mindanao Id., 15.v.2010, HC”; 2 ♂♂, 1♀ (RJTV), “Siloy, Calamba, Missamis Occidental, Mindanao Id., 27.vii.2010, RJTV”.

Diagnosis.— The species is similar to P. daku spec. nov. with bluish labrum and robust lower branch of the cerci. It differs from that species in the smaller tooth on the tip of the upper branch of the cerci, the acutely incurved tooth on the lower branch, and the shape of the paraprocts in lateral view.

Description of male.— Labium and mandible bases yellow, brownish distally. Labrum mostly bluish with yellow free margin and black basal markings extending centrally as a bulb shaped marking. Genae largely yellow. Anteclypeus black and bluish. Postclypeus is equal or narrower in width than the anterior portion of frons, mainly black with transverse sinuous yellow streak across the middle. Frons with distinct ridge: anterior portion bluish; posterior portion black. The rest of the head is bronzy black except for whitish base of antennae, a yellow streak between antennae and lateral ocelli, and slender yellow streak perpendicular to the eye margin at the level of lateral ocelli. Hind margin of the occiput brownish.

Thorax.— Anterior lobe of prothorax bluish with black anterior margin, median lobe flat, orange, posterior lobe simple and collar-like, bluish with a dirty orange centre, propleuron largely blue. Synthorax – mesinfraepisternum largely yellowish. Mesepisternum orange except for bluish streak on both sides of the dorsal carina. Mesepimeron largely yellowish. The rest of the synthorax is mostly bluish. Legs yellowish. Tarsal claws with distinct denticle.

Wings.— Broad, hyaline with black veins. Venation as for genus, with 14 and 13 Px in forewing and hindwing respectively; R3 at Px5-6 and Px4-5; IR2 at Px8-9 and Px8. Pterostigma dark brown with narrow pale margin, rectangular.

Abdomen.— S1-S2 black dorsally, blue laterally. S3-S4 black dorsally, with a bluish basal annulus, becoming pale on the lower half laterally; S5-S8 black dorsally, pale bluish on the lower third laterally; S9 black; S10 black with large pale lateral patch. Cerci (figs 14, 18) yellowish, longer than S10. The upper branch is hook-shaped, tapered at the bend, with rounded tip equipped with blunt black interior tooth (not visible in the figures). The lower branch is shorter than upper (fig. 18), robust, cylindrical, its tip expanded with large acutely incurved interior black tooth (fig 14). Paraprocts broad-based with short broad tubercle directed slightly away from the margin of S10, gently rounded at the top (fig 18).

Measurements [mm].— Abdomen + cerci: 37-47; Hw: 27-30

Variation.— The transverse yellow streak on the postclypeus is sometimes attenuated, forming a series of three or five ovoid spots, its outer side with pale spot also. Arc sometimes well distal to Ax2. The downward portion of the upper branch of the cerci is sometimes a little broadened ventrally. The upper branch of the cerci shows a degree of variation on the dorso-medial tubercle.

Description of female.— Colour pattern and venation similar to the male except for the blue in the posterior pronotal lobe is restricted to the lateral portion. Wing veins dark brown; S1-S6 reddish brown except pale basal portion of S3-S6; S7 blackish with pale basal third; S8-S10 yellowish except for black dorsum.

Measurements [mm].— Abdomen + cerci: 35-47; Hw: 21-30.

Remarks.— The size of the species is very variable. It appears that larger specimens are obtained from larger plants.

Distribution.— Mindanao and Dinagat islands.

Habitat.— The species is restricted to phytotelmata. Leaf axils of Pandanus and Freycinetia species are the preferred habitat.

Pandanobasis mcgregori (Needham & Gyger, 1939), comb. nov.

(figs 15, 19, 23)
Pericnemis mcgregori Needham & Gyger, 1939 (original description).
Amphicnemis mcgregori (Needham & Gyger, 1939); Lieftinck, 1940; Hämäläinen & Müller, 1997.
Material.— 1 ♂ (SMF), “Mt. Banahaw, Luzon, Phil(ippines), 26.ii.1914, G. Boettcher”.

Diagnosis.— The species is close to P. curacha spec. nov. with a relatively slender lower branch of cerci. It differs from P. curacha by the bluish labrum, minute tooth in the upper branch of cerci, expanded tip of the lower branch of cerci, and slender and slanted position of the tubercle of the paraprocts.

Description of male.— Labium and mandible bases yellowish. Labrum bluish except for dark brown basal markings extended centrally. Genae mostly bluish. Anteclypeus pale with black lateral margin, and small brown central marks. Postclypeus blackish brown except for large ovoid bluish streak at the centre, and a number of small bluish circular spots. Frons with distinct ridge; anterior portion bluish, posterior portion black. Rest of the head bronzy black except for bluish streak on the anterior margin at the base of antennae; brownish antennae; ovoid yellow streak between antennae and lateral ocelli; slender bluish streak on the anterior margin of the post-ocular area behind the antennae and brownish hind margin of the occiput.

Thorax.— Anterior lobe of prothorax bluish except for short, erect brownish anterior part. Median lobe is gently domed, yellowish. Posterior lobe bluish, broadly fan-shaped, free margin slightly up-curved centrally, smoothly rounded laterally. Propleuron bluish. Synthorax – mesinfraepisternum yellowish; mesepisternum bluish green; mesepimeron bluish with yellowish tint near legs; metepisternum and metepimeron bluish. Legs yellowish; tarsal claws with distinct denticle.

Wings.— Hyaline with dark brown veins. Venation as for genus, with 12-13 and 11 Px in forewing and hindwing respectively; R3 at Px5 and Px4; IR2 at Px8 and Px7. Pterostigma rectangular, brownish.

Abdomen.— S1 bluish with narrow dorsal brownish streak. S2 blue except for brownish dorsum; S3-S7 brownish, darkened distally and paler laterally. S8-S10 blackish, paler laterally, more extensive pale marking on S10. Cerci (figs 15, 19) light brown, longer than S10. The upper branch is directed upwards in its basal ca 2/3, then bent sharply downwards, hook-shaped (fig. 19), a broad dorsal interior tubercle at the down turn (fig. 15), the tip rounded with minute black tooth. Lower branch of cerci (fig. 19) shorter than the upper branch; its tip slightly expanded with black interior tooth (fig. 15). Paraprocts with broad base and short slender dorsal tubercle, directed slightly to rear.

Measurements [mm].— Abdomen + cerci: 37; Hw: 24.

Female unknown.

Remark.— The single specimen available for study is identified as P. mcgregori, with some hesitation. It agrees closely with the original description (Needham & Gyger 1939) except for the presence of a small tooth on the tip of the upper branch of the cerci that was not mentioned or illustrated in the description. The tubercle on the paraprocts (a diagnostic character for the genus) matches quite well with the illustration in the original description.

Distribution.— Luzon Island.

Pandanobasis curacha spec. nov.

(figs 16, 20, 23)
Amphicnemis cantuga Hämäläinen & Müller, 1997 (part, populations from Samar, Biliran and Homonhon).
Material (all in RMNH unless otherwise stated).— Holotype: ♂ (RMNH), “Philippines, Samar Id, Northern Samar, Las Navas, Brgy. San Isidro, 100-350 m, 22-28.v.1997, Alex Buenafe”.
Paratypes: Philippines: 1 ♀, “Samar Id, Western Samar Prov., Basey, Mt. Sohoton, 150-200 m, 10-18.vii.1994, Th. Borromeo”; 2 ♀♀, “Samar Id, Northern Samar, Las Navas, Brgy. San Isidro, 100-350 m, 22-28.v.1997, Alex Buenafe”; 1 ♀, “Samar Id, San Rafael, E. Samar, 50-180 m, 21-24.iv.1992, Th. Borromeo jr”; 1 ♀, “Samar Id, Oras, Eastern Samar, 12.iii.1994, T. Borromeo”; 1 ♀, “Samar Id, W. Samar Prov., Hinubangan, Arizona area, 100-280 m, 5-12.v.1997, Alex Buenafe”.
Other material, Philippines: 1 ♂, “Mindanao Id, Surigao del Sur, San Miguel, Suba River, 150-250 m, 13-15.iv.1995, Müller/Buenafe/ Gorostiza”; 1 ♂ 1 ♀, “Biliran Id, Leyte Prov., Naval, Mt. Sayoa, 200-400 m, Horonan Creek, 30.x-3.ix.1992, Th. Borromeo”; 1 ♂, “Homonhon Id, Eastern Samar Prov., Magallanes Point, 28.i.1989, F. Lagramada”; 1 ♂ (RJTV), “Cervates, Lope de Vega, Samar Is, 10.ix.2009, RJTV/HC”.

Diagnosis.— The rounded tip of the upper branch of the cerci without a tooth and the tubercle of the paraprocts directed straight up are diagnostic, as is the yellowish-brown labrum.

Etymology.— From Waray (local dialect in eastern Visayas) word ‘curacha’, which refers to the traditional dance in the area. A noun in apposition.

Description of holotype male.— Labium and mandible bases yellowish. Labrum yellowish-brown except for black lateral and basal borders, extended narrowly centrally. Genae largely yellowish. Anteclypeus pale with brownish marks. Postclypeus black except for brownish, transverse streak across the center, narrower than the anterior portion of frons. Frons with distinct ridge: anterior (vertical) portion yellow, posterior portion of frons black. Rest of the head bronzy, metallic green except for whitish streak on antenna bases; brownish antennae; a small yellow streak between antennae and lateral ocelli and paired, yellow, slender streaks at the hind margin of occiput.

Thorax.— Anterior lobe of pronotum is short and erect, bluish. Median lobe flat, orange-brown. Posterior lobe simple and collar-like, mostly orange. Synthorax – mesinfraepisternum mostly orange; mesepisternum largely orange; mesepimeron orange near mesinfraepisternum, otherwise bluish. The rest of synthorax is bluish, with faint orange streak in the metepisternum. Legs – coxae and trochanters pale. Femora and tibiae orange including femoral spines. Tarsal claws with distinct denticle.

Wings.— Broad hyaline with black veins. Venation as for genus, with 12-13 and 11-12 Px in forewing and hindwing respectively; R3 at Px5 and Px4; IR2 at Px7-8 and Px7. Pterostigma brown with pale margins, rectangular.

Abdomen.— S1-S2 yellowish except for black dorsum; S3 black dorsally brown laterally with a basal annulus interrupted dorsally; S4-S7 black above, brown laterally with interrupted pale basal annulus. S8-S9 black. S10 black, pale in the lower lateral parts. Cerci (figs 16, 20) yellowish, longer than S10. The upper branch hook-shaped (fig. 20), tip smoothly rounded. Lower branch shorter than the upper branch, tapered in the middle and slightly expanded at the tip is equipped with black, blunt tooth interior tooth (fig 16). Tubercle of the paraprocts slender with rounded tip, directed straight upwards so that it appears directed towards the distal margin of S10 (fig 20).

Measurements for holotype [mm].— Abdomen + cerci: 40; Hw: 25.

Variation in male.— There is variation in dark markings on the labrum and markings of the postclypeus. In some populations the tubercle of the paraprocts is more strongly directed towards S10 (see Remark below).

Description of female.— Colour pattern and venation similar to the male except as noted here. Metepisternum and metepimeron yellow; wing veins brown; S1 reddish, black dorsally apically and laterally near base; S2-S7 reddish blackening distally, with pale baso-ventral patch; S8 black with pale lateral spots; S9 black with lateral pale spot; S10 brownish black.

Measurements [mm].— Abdomen + cerci: 43; Hw: 26.

Remark.— The two specimens (both sexes) from Biliran Island, and a single male specimen from Surigao del Sur, Mindanao, are presently assigned to this species. However, they differ from the Samar population in some details of the cerci. Further material is needed to confirm the taxonomic affiliation of these populations and they are not included on the distribution map of the species.

Distribution.— Samar, Biliran, Homonhon and Mindanao islands (see Remark).

Pandanobasis daku spec. nov.

(figs 17, 21, 23)
Amphicnemis cantuga (Needham & Gyger, 1939); Hämäläinen & Müller, 1997 (part, population from Leyte)
Material.— Holotype, ♂ (RMNH), “Philippines, Leyte Id, Mahaplag, Hilusig, Mt. Bolocaue, 700 m, 28.xi.1989. Th. Borromeo Jr”.

Diagnosis.— The species is close to P. cantuga but differs from that species by the elongate tubercle of the paraprocts.

Etymology.— From the Pilipino word daku, meaning ‘large’: referring to the large elongate tubercle present on the paraprocts of the species. A noun in apposition.

Description of holotype male.— Labium and mandible bases yellowish. Labrum bluish except for yellow anterior margin and narrow black lateral and basal borders, extended centrally as an inverted bulb-shaped patch. Genae mostly yellowish. Anteclypeus whitish with brown marks. Postclypeus black except for transverse, sinuous, bluish streak across the centre; narrower than anterior portion of frons. Frons with distinct ridge, anterior (vertical) portion olive green, posterior portion of frons and the rest of the head black, bronzy at the posterior portion, except for pale markings at antennae bases; whitish top of scape; dark brown antennae; yellow ovoid streak between antennae and lateral ocelli; brown hind margin of the occiput.

Thorax.— Anterior lobe of prothorax short and erect, bluish except for black anterior margin. Median lobe gently domed, obscurely orange and blue. Posterior lobe is collar-like, dented at the middle, bluish except for orange central portion. Propleuron blue with orange streak. Synthorax – mesinfraepisternum largely orange. Mesepisternum largely orange. Mesepimeron bluish, orange below mesopleural sutre; metepisternum mostly olive; metepimeron bluish near metapleural suture, olive below. Legs orange. Tarsal claws with distinct denticle.

Wings.— Broad, hyaline with dark brown veins. Venation as for genus, with 13 and 12-13 Px in forewing and hindwing respectively; R3 at Px4-5 and Px4; IR2 at Px8 in all wings. Pterostigma rectangular, brown, costal side a little shorter than subcostal side.

Abdomen.— S1-S2 bluish green except for black dorsum. S3 dark brown, paler laterally and with bluish basal annulus; S4-S7 blackish with for bluish basal annulus and pale lateral basal quarter; S8-S9 black; S10 black with large pale square lateral patch. Cerci (figs 17, 21) yellowish with black tip, longer than S10. The upper branch hook-shaped (fig. 21): a broad interior tubercle at the downturn, the tip a little swollen with broad incurved tooth. Lower branch robust, shorter than upper branch, its tip slightly expanded, a large internal tooth at the tip (fig 17). Tubercle of the paraprocts robust with rounded expanded tip, more than half the length of the lower branch.

Measurements for holotype [mm].— Abdomen + cerci: 42; Hw: 26.

Female unknown.

Distribution.— Leyte Island.

Habitat.— Unknown.

3) Amphicnemis furcata-group

This group is the closest in general appearance to Amphicnemis s.s. from Sundaland. It differs from Amphicnemis s.s. by the presence of a tubercle on the base of the ligula. It only shares this character with Pericnemis and Luzonobasis gen. nov., among the Old World Teinobasini. Needham & Gyger (1939), although having not seen the species, already noted the difference and suggested a “better generic allocation pending availability of more material for study”.

Among the Old World Teinobasini with the upper branch of the cerci longer than S10 (Amphicnemis, Pericnemis, Luzonobasis gen. nov. and Pandanobasis gen. nov.), the group is characterized by a rudimentary lower branch, about 1/5 the length of the upper branch, and the forked upper branch of the cerci. This species-group is considered to form a new genus Sangabasis gen. nov. It is known only from the Philippines and is probably endemic.

Sangabasis gen. nov.

(figs 3, 4, 6, 13)

Type species.— Amphicnemis braulitae Villanueva, 2005 by present designation.

Etymology.— Combination of the word ‘Sanga’, which in the local Cebuano dialect means ‘fork/branch’ referring to its cerci and the suffix ‘basis’ indicating its close relationship with other Teinobasini.

Description of genus.— Slender coenagrionids with predominantly metallic green thorax. Frons angulate in profile with postclypeus broader than anterior portion of frons. Labrum shiny black except for its yellowish anterior margin. Anterior portion of the head generally pale or yellowish except for the black postclypeus. Posterior half of the head black or dark metallic green except for pale streak on the anterior margin at the base of pedicle, and whitish base of scape. Post-ocular spot absent. A pair of tubercles is present in the post-ocular area (fig. 3). The ocelli and occiput are deeply set in relation to the eye margin, making it appear prominently bulging. Prothorax generally metallic green; anterior and median pronotal lobes simple while the posterior lobe has distinct middle and lateral portions (except for three species with paired processes) produced into elongate or triangular process. Synthorax is generally metallic green with a distinct tubercle or ridge on the dorsal carina (fig. 4). Wings hyaline with black veins; Arc at or just slightly distal Ax2, Ac near to Ax2, petiolation ceases proximal to the level of Arc, R4 at or close to subnodus, IR3 distal to subnodus by not more than one cell length. Pterostigma is brown, square or a little rectangular with costal side slightly shorter than subcostal side. Legs weak and short, generally pale with blackening at the joints, posterior margin of femora and some along the posterior and anterior margins of tibiae. Femoral spines black, shorter than the intervening space; tarsal claws without denticle. Abdomen is generally black with metallic greenish reflection on the dorsum, paler ventrally with pale basal ring at S3-S7. Male cerci (fig. 13) are pale or sometimes blackened, twice or more as long as S10. Upper branch of the cerci bifurcated at about its basal third with longer outer and shorter inner branch. The lower branch of cerci rudimentary, generally present and visible for most species in lateral or ventral view, mostly slender whitish vermiform or darkened and slightly robust; just reaching the base of the inner fork, at most 1/5 the upper branch’s length. Paraprocts are squat with a short rounded tubercle. Male genital ligula with a fin-like tubercle in the distal portion of its base (fig. 6), a well developed terminal fold that triangularly folded with expanded tip. Female S8 lacking vulvar spine; cerci shorter than S10; ovipositor surpassing the outer margin of S10.

Larva.— unknown.

Diagnosis.— The rudimentary lower branch of the cerci and the long (twice the length of S10) bifurcate upper branch clearly distinguishes Sangabasis gen. nov. from all related genera. Sangabasis gen. nov. together with Amphicnemis, Luzonobasis gen. nov., Pandanobasis gen nov. and Pericnemis, differ from the other Old World Teinobasini (Melanesobasis, Papuagrion, Plagulibasis, and Teinobasis) in having cerci longer than S10. Sangabasis gen. nov. differs from its close relatives by the bifurcated upper branch and rudimentary lower branch of the cerci; the lower branch is about 1/5 the length of the upper branch (and absent in two species). The general stature of Sangabasis gen. nov. species closely resembles that of Amphicnemis s.s. and some small Teinobasis species. Its metallic coloration and especially the squat paraprocts set it apart from Teinobasis. The three genera have prominently bulging eyes. However, Sangabasis gen. nov. differs from the other two genera in having a tubercle in the post-ocular area (fig. 3), and on the dorsal carina of some species (fig. 4). In Sangabasis gen. nov. the vein R4 originates at subnodus and is well separate from IR3. Teinobasis has R4 and IR3 very close or even fused, standing at subnodus, or they are well separated but R4 originates just distal to subnodus. Amphicnemis has R4 placed well distal to subnodus and IR3 slightly further distal.

Sangabasis gen. nov., Luzonobasis gen. nov. and Pericnemis possess a distinct ridge or tubercle in the distal portion of the base of the ligula, a character absent in other Old World relatives. Sangabasis gen. nov. differs from Luzonobasis gen. nov. and Pericnemis in having a more slender stature. In Sangabasis gen. nov. the postocular region of the head is deeply concave and bears tubercles.

The genus Sangabasis gen. nov. includes four previously described: Sangabasis braulitae (Villanueva, 2005) comb. nov. (type species); Sangabasis circularis (Lieftinck, 1974) comb. nov.; Sangabasis dentifer (Needham and Gyger, 1939) comb. nov.; Sangabasis furcata (Brauer, 1868) comb. nov.

A number of additional species will be described and a key to the species will be provided in a separate publication (Villanueva & Dow in preparation).

4) Rest of the Philippine ‘Amphicnemis’

This group includes five previously known Philippine species, all of which were originally described as Pericnemis species, and a large number of new species that will be named and described in a separate publication. This group has a distinct tubercle or ridge on the distal portion of the base of the ligula (e.g. fig. 7). All members are large, robust species and closely resemble Luzonobasis gen. nov. except for a very short epiproct and less modified posterior lobe of the male prothorax. The group differs from Sangabasis gen. nov., that also has a tubercle on the ligula, in having weakly concave postocular areas on the head, but without a tubercle there or on the dorsal carina, and cerci with a simple upper branch and long lower branch.

The presence of a tubercle or ridge on the distal portion on the base of the ligula separates the group from Amphicnemis s.s. from Sundaland. It also differs in stature, being large and robust. The origin of R4 in the group is close to the subnodus, and the cerci are long but simple, while in Sundaland Amphicnemis s.s. R4 originates distal to subnodus and the cerci are equipped with spine and/or tubercle.

Comparison with Pericnemis species from Sundaland has revealed the affinity of this group of Philippine species with that genus. The stature of this group of Philippine Amphicnemis s.l. is large and robust, similar to P. stictica and P. triangularis Laidlaw, 1931. The cerci of the group are long and simple, similar to Pericnemis. For these reasons I decided to transfer this group back to Pericnemis. A number of distinct subgroups are present within Pericnemis as understood here and it may be necessary to divide the genus further. Pericnemis will be treated in its entirety in a separate publication (Villanueva & Dow in preparation).

Acknowledgements


Special thanks to Rory Dow for the final review of the manuscript and making the needed line drawings, and Matti Hämäläinen for the review of the initial draft. Rory Dow also loaned his Pericnemis stictica and P. triangularis for this study. The author is indebted to KD Dijkstra, Rory Dow, Dirk Gassmann, Matti Hämäläinen, Vincent Kalkman and Jan van Tol for their constant support to his odonatological study, for the various help during the preparation of this manuscript, and for the discussion and company while in Leiden. Rosser Garrison provided some literature and relevant information. The author is also thankful to Victor Gapud for permission to study his collection and Chung-Ping Lin for the joint excursion resulting to the discovery of several new species. Hilario Cahilog provided much help in collecting several interesting species.

This paper is one of the results of my visit to Naturalis Biodiversity Center sponsored by a Martin Fellowship in Naturalis, Leiden, The Netherlands.

Received: 2.xii.2011

Accepted: 12.iii.2012

Editor: K.D.B. Dijkstra

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FIG2

Figs 1-2. 1: Pandanobasis cantuga in life; 2: Pterostigma of Luzonobasis glauca.

FIG2

Figs 3-7. 3: Dorsal view of head of Sangabasis spec. nov., showing the angulate frons and postocular tubercle (circled); 4: Lateral view of mesepisternum of Sangabasis braulitae, showing the tubercle on the dorsal carina; 5: Genital ligula of Pandanobasis cantuga; 6: Genital ligula of Sangicnemis dentifer; 7: Genital ligula of Pericnemis lestoides.

FIG2

Figs 8-13. Luzonobasis glauca. 8: Dorsal view of posterior prontal lobe of male; 9: Dorsal view of posterior prontal lobe of female; 10: Dorsal view of male anal cerci; 11: lateral view of male anal appendages. Pericnemis stictica; 12: Lateral view of male anal appendages. Sangancemis braulitae; 13: Lateral view of male anal appendages.

FIG2

Figs 14-17. Dorsal view of male cerci of Pandanobasis species. 14: P. cantuga; 15: P. mcgregori; 16: P. curacha spec. nov.; 17: P. daku spec. nov.

FIG2

Figs 18-21. Lateral view of male anal appendages of Pandanobasis species. 18: P. cantuga; 19: P. mcgregori; 20: P. curacha spec. nov.; 21: P. daku spec. nov.

FIG2

Fig. 22: Distribution of Luzonobasis glauca.

FIG2

Fig. 23: Distribution of Pandanobasis species: P. cantuga – triangle; P. mcgregori – star; P. curacha spec. nov. – square; P. daku spec. nov. – circle.