Sangabasis circularis ( Lieftinck, 1974 )

Villanueva, R. J. T. & Dow, R. A., 2014, Review of the Philippine taxa formerly assigned to the genus Amphicnemis Selys, II. Genus Sangabasis with descriptions of eight new species (Odonata: Coenagrionidae), Zootaxa 3815 (1), pp. 1-28 : 12-13

Sangabasis circularis ( Lieftinck, 1974)

( Figs. 11 , 22 , 32 , 46 , 58 , 69 )

Amphicnemis circularis Lieftinck 1974: 134 –137, Figs. 19–21 (original description ♂, Tawi Tawi, Philippines);— Hämäläinen & Müller (1997: 259, 276: note 2, 278: note 30);— Villanueva (2005: 80, comparison with S. braulitae ). Sangabasis circularis (Lieftinck) ;—Villanueva (2012: 582, 595, transferred to Sangabasis).

Type material. Holotype: ♂, Philippines, Tawi–Tawi, Lapid–Lapid, 19 xi 1961, leg. Noona Dan Expedition 1961–1962, in RMNH. Paratype: ♂, Philippines, Tawi–Tawi, Lapid–Lapid at Manatik Channel, 20 ix 1961, leg. Noona Dan Expedition 1961–1962, in RMNH.

Other material (all Philippines, Tawi–Tawi Province, all in RMNH unless otherwise stated). Tawi–Tawi Island: 4 ♂, Tarawakan, 100m, 22–26 vi 1992, leg. T. Borromeo; 7 ♂, same location, 60–100m, 7–9 iv 1990, leg. R.A. Müller; ♀, Tarawakan, Batu–batu, Magsag–caw, 14–16 iii 1991, leg. T. Borromeo Jr.; ♂, Languyan, 80–100m, 9 vi 1990 leg. R.A. Muller. Bongao Island: ♂, Bongao Peak, 200m, 10 ii 1989, leg. C. Treadaway & T. Borromeo. Sanga–Sanga Island: 6 ♀, 2–8 iii 1992, leg. T. Borromeo; 2 ♂, 2 ♀, Boloboc, 25 vi 1988, W. Catal; ♀, Boloboc, 1–11 i 1990 leg. T. Boromeo Jr; ♂, Boloboc, 10–12 iii 1991, leg. T. Borromeo jr.”; ♂, ♀, Boloboc, 15m, 18 iv – 2 vii 1992, leg. T. Borromeo; 2 ♀, Boloboc, 29 i – 4 ii 1994, leg. T. Borromeo; 7 ♂, 2 f♀, Boloboc, 15m, 18 vi – 2 vii 1992, leg. T. Borromeo; 10 ♂, 2 f♀, Boloboc, Lakit–lakit, 8 i 1989, leg. W. Catal. Sibutu Island: 10 ♂, Kaban–kaban, Sibutu Hill area, 0–50m, 15 vi 1990, leg. R.A. Müller.

Description of male. Head: Labium pale, and mandibles bases brown with broad pale border except adjacent to labrum. Labrum shiny black except for yellow distal third. Genae pale, pale colour continued to eye margin and narrowly along eye margin from ridge of frons to level of antennal sockets. Anteclypeus pale blue adjacent to labrum, black above, boundary of two colours irregular. Postclypeus black. Frons black, with distinct ridge, anterior face with paired transverse yellow streaks separated centrally. Vertex black with metallic reflection. Pale vertical streaks on antennal sockets and scape. Rest of antennae brown. Remainder of head dark metallic green. Distinct rounded tubercle situated anteriorly beside eye margin in postocular area.

Thorax: Prothorax dark metallic green except for pale transverse streak on crest of anterior lobe, lower part of propleuron. Shelf of posterior lobe ( Fig. 11 ) short with corners produced as short spurs directed rearward and slightly downward. Horns of posterior lobe long, rearward and downward directed, with tip at level of upper third of mesinfraepisternum. Synthorax ( Fig. 32 ) with dorsal carina equipped with subtriangular process arising at anterior 1/4 of its length. Mesinfraepisternum metallic green with irregular pale borders. Mesepisternum metallic green, mesepimeron mostly metallic green ( Fig. 32 ). Metepisternum pale, large metallic green marking adjacent to antealar carina. Metepimeron pale. Legs pale with dark spines, blackish streaks on extensor surfaces of femur and tibia and dark markings around joint of femur and tibia. Tarsi without denticle. Wings hyaline with dark brown veins; Arc at level of Ax2; Ac near Ax2; petiolation ceases just before level of Arc. R4 arises at subnodus; IR3 distal to subnodus. 15–16 Px in Fw, 14–15 in Hw; Pt rectangular, brown, costal side a little shorter than subcostal side.

Abdomen: S1 dorsum black, attenuated basally. S2 dorsum black, becoming pale lower on sides; S3–6 brownish, paler lower laterally with narrow, faint pale basal ring; S7–9 black, pale lower laterally; S10 black. Cerci yellowish, almost three times length of S10. Fork of upper branch at ca 1/3 length of upper branch ( Fig. 58 ). In lateral view upper branch shaped as in Fig. 46 , with small black tooth at tip. Spur well visible in lateral view where it appears just longer than distance from S10 to its base. In dorsal view spur broad at base, its surface devoid of long setae, shorter than distance from base of S10 to fork of upper branch. Lower branch whitish, vermiform, hugging ventral surface of upper branch with tip just beyond level of spur of upper branch in lateral view. Paraprocts typical for genus.

Measurements (mm): abdomen including cerci 39–42, Hw 23–24.

Female. Similar to male except for broader yellow anterior portion of labrum. Black mark on mandible bases reduced to small ovoid spot. Anterior face of frons extensively yellow. Shelf of posterior pronotal lobe with corners produced as upward-curved horns ( Fig. 22 ). S9 black only on dorsum.

Measurements (mm): abdomen 38–41, Hw 25–27.

Diagnosis. The parallel orientation of the horns and produced corners of the shelf of the posterior pronotal lobe are diagnostic, as is the shape of the upper branch of the cercus: acutely curved and distinctly expanded apically in lateral view.

Remarks. The lower branch of the cercus rests partly within a groove in the ventral surface of the upper branch and is hidden in lateral view in some specimens.

The population from Sibutu Island differs in the shape of the middle portion of the posterior pronotal lobe, which is raised centrally. The absence of further distinguishing characters leads us to concur with M. Hämäläinen, who first studied this population, in considering this Sibutu form as merely a variant of S. circularis .

Figures

FIGURE 69. Distribution of S. circularis.

FIGURES 8 – 15. Male posterior pronotal lobe, dorsal views: (8) S. braulitae Camiguin; (9) S. braulitae Homonhan; (10) S. bulba holotype; (11) S. circularis Tawi-Tawi; (12) S. dentifer Mindanao, Davao Oriental; (13) S. feliculoi paratype; (14) S. furcata; (15) S. zamboanga holotype.

FIGURES 19 – 26. Female posterior pronotal lobe, dorsal views: (19) S. bukid paratype; (20) S. bulba paratype; (21) S. carmelae paratype; (22) S. circularis Tawi-Tawi; (23) S. dentifer Dinagat; (24) S. dentifer Mindanao; (25) S. feliculoi paratype; (26) S. furcata.

FIGURES 27 – 32. Lateral views of male synthorax: (27) S. braulitae holotype; (28) S. bukid holotype; (29) S. bulba holotype; (30) S. cahilogi holotype; (31) S. carmelae holotype; (32) S. circularis Tawi-Tawi Island.

FIGURES 41 – 46. Lateral view of male anal appendages: (41) S. braulitae holotype; (42) S. bukid holotype; (43) S. bulba holotype; (44) S. cahilogi holotype; (45) S. carmelae holotype; (46) S. circularis Tawi-Tawi.

FIGURES 53 – 58. Dorsal view of male anal appendages: (53) S. braulitae holotype; (54) S. bukid holotype; (55) S. bulba holotype; (56) S. cahilogi holotype; (57) S. carmelae holotype; (58) S. circularis Sibutu.