Sangabasis bulba, Villanueva, R. J. T. & Dow, R. A., 2014

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 : 6-7

Sangabasis bulba sp. nov.

( Figs. 10 , 20 , 29 , 43 , 55 , 66 )

Type Material. Holotype: ♂, Philippines, Mindoro, Mindoro Oriental, Victoria, Alcate, 7 iv 1954, in RMNH. Paratypes: ♂, location as holotype, 11 iv 1954, in RMNH; ♀, same island and province, San Luis, 17 iv 1954, in RMNH.

Etymology. bulba after the Latin word ‘bulbus’ (a bulb), referring to the structure of the lateral portion of the posterior pronotal lobe of the prothorax.

Description of holotype male. Head: Labium and mandible bases pale, except for dark mark near labrum on mandible base. 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 mostly pale with dark central marking beneath postclypeus. Postclypeus black. Frons black, with distinct ridge, anterior face almost entirely occupied by broad transverse yellow streak. Vertex black with metallic reflection, broad yellow streak on antennal socket, top of scape pale, pale streak along anterior face of pedicel, rest of antennae brown. Remainder of head dark metallic green.

Thorax: Prothorax dark metallic green except for pale transverse streak on crest of anterior lobe, lower part of propleuron. Rear of posterior pronotal lobe produced into pair of large, flat, ca triangular processes (tip of left one broken off) directed rearwards ( Fig. 10 ). Synthorax ( Fig. 29 ) with dorsal carina without distinct tubercle but smoothly raised along anterior 1/4 of synthorax length. Mesinfraepisternum mostly metallic green. Mesepisternum metallic green, mesepimeron mostly metallic green with tiny pale streak along interpleural suture ( Fig. 29 ). Metepisternum pale, large metallic green marking adjacent to antealar carina, slightly separated from small dark mark spanning metapleural suture, metepimeron otherwise pale. Legs with coxa and trochanter pale, femur and tibia pale with dark spines, blackish streaks on extensor surfaces of femur and dark markings around joint of femur and tibia. Tarsi brownish, without denticle. Wings hyaline with black veins. Arc at level of Ax2, Ac near to Ax2, petiolation ceases before level of Arc. R4 arises at subnodus, IR3 slightly distal (1/4 cell length) to subnodus, 14 Px in Fw, 13–14 Px in Hw. Pt brown, centrally darkened, approximately square with costal and basal sides a little shorter than subcostal and distal sides.

Abdomen: S1 with large dorsal black patch that broadens apically. S2 black dorsally, pale lower on sides. S3–8 brown, darkening distally, paler lower laterally and with narrow basal pale annulus. S9 black except for pale lateral marking, S10 black dorsally and yellow on lower half of sides. Cerci blackish, brown interiorly, more than twice length of S10. Fork of upper branch at ca 1/2 length of upper branch ( Fig. 54 ). In lateral view upper branch shaped as in Fig. 43 , with small black tooth interiorly at tip (not visible in figures). Spur of upper branch in dorsal view appearing as an interior shelf with dense setae on upper inner surface, abruptly terminating at fork. In lateral view appearing as robust ventral tooth. Lower branch visible in lateral view, short but robust, pointed tip at ca 1/2 distance from S10 to fork of upper branch. Paraprocts typical for genus.

Measurements (mm): abdomen including cerci 50, Hw 29.

Variation in paratype male: Tip of triangular process of posterior pronotal lobe more swollen, balloon-like.

Female. Similar to male except: mandible bases with larger, ca square black mark. Yellow marking on anterior face of frons narrowly divided centrally. Vertex and rest of head metallic green. Prothorax illustrated in Fig. 20 . S9 pale with black mark restricted to dorsum and narrow apical black ring.

Measurements (mm): abdomen 45, Hw 30.

Diagnosis. The absence of any postocular tubercle serves to distinguish S. bulba from all other Sangabasis species except S. cahilogi . It is distinguished from S. cahilogi by the shape and position of the spur of the upper branch of the cercus. The shape of the posterior pronotal lobe is unique in the genus.

Figures

FIGURE 66. Distribution of S. bulba (black triangle), S. furcata (black circle) and S. zamboanga (black sqaure).

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.