Trigonocarinatus

POORANI, J., 2024, An illustrated guide to lady beetles (Coleoptera: Coccinellidae) of the Indian Subcontinent. Part 3. Tribe Aspidimerini, Zootaxa 5431 (1), pp. 1-89 : 76

Trigonocarinatus nr. bilineatus (Kapur)

( Fig. 57 )

Diagnosis. The elytral pattern, shape and position of the elytral maculae in this species are unique ( Fig. 57a ). However, the male genitalia ( Fig. 57f–i ), particularly the penis guide ( Fig. 57f ) of this species in lateral view, are similar to that illustrated by Kapur (1948) for C. bilineatus (see notes on T. bilineatus ). But the female genitalia ( Fig. 57j ) has a distinctly shorter and narrower sperm duct and the spermatheca ( Fig. 57k ) is also apically less narrow. In view of the uncertainty over the identity of T. bilineatus , it is only tentatively identified and briefly described below.

Brief Description. Length: 1.90–2.10 mm; width: 1.60–1.80 mm. Form broad oval, dorsum convex and densely pubescent. Head yellow in male with a black frontal spot, black in female. Pronotum black except lateral flanks yellow, posterolateral corners black. Scutellum black. Elytra black, with two orange-yellow spots on each elytron, first one a little above midline, transverse quadrate, second spot apical and oblique oval ( Fig. 57a ). Ventral side dark brownish, mouthparts yellowish brown, tarsi of legs lighter, yellowish brown. Head densely punctate, punctures separated by 0.5–1.0 diameter. Antenna 9-segmented, club fusiform and distinctly longer than width of scape ( Fig. 57b ). Mentum cordiform, anterior margin with a broadly triangular emargination ( Fig. 57c ). Prosternum without a triangular fold, prosternal carinae elongate, inverted Y-shaped with a barely visible stem ( Fig. 57d ). Abdominal postcoxal line incomplete ( Fig. 57e ). Male genitalia ( Fig. 57f–i ) as illustrated, penis guide broadest around middle and distinctly longer than parameres in lateral view ( Fig. 57f ), elongate lanceolate and apically triangular in ventral view ( Fig. 57g ), parameres with few elongate apical setae; penis ( Fig. 57h ) slender and strongly curved with a distinct capsule, apex lanceolate ( Fig. 57i ). Female genitalia ( Fig. 57j ) as illustrated, spermatheca ( Fig. 57k ) strongly curved, distinctly narrowed apically, only ramus well defined.

Material examined. “ INDIA: Andaman & Nicobar, Middle Andaman: Rangat, 12°30’19.4’’N 92°55’05.9”E, 17.2m, 20.iv.2014, Light trap, Yeshwanth, H.M. ( NBAIR); “ INDIA: Andaman & Nicobar, North Andaman , Diglipur, 13°14’53.9”N 92°58’37.5”E, 15mts, 21.iv.2014, Light trap, Yeshwanth, H.M. ( NBAIR) .

Distribution. India: Andaman Islands.

Prey / associated habitat. Veenakumari & Mohanraj (2007) recorded Cryptogonus sp. nr. bilineatus Kapur on coconut from the Andaman Islands, which is most likely to be this species. Attracted to light (label data).

Figures

FIGURE 57. Trigonocarinatus nr. bilineatus (Kapur): a. dorsal view; b. antenna; c. labium; d. prosternum; e. abdomen, male; f–i. male genitalia: f. tegmen, lateral view; g. tegmen, ventral view; h. penis; i. penis apex; j. female genitalia; k. spermatheca.