Tegyrius nigrotibialis, Prathapan & Viraktamath, 2009

Prathapan, K. D. & Viraktamath, C. A., 2009, Revision of Tegyrius (Coleoptera: Chrysomelidae: Galerucinae: Alticini), with descriptions of eight new species, Zoological Journal of the Linnean Society 157 (2), pp. 326-358 : 348-350

TEGYRIUS NIGROTIBIALIS SP. NOV.

( FIGS 79–89 )

Distribution: India (Tamil Nadu).

Host plant: Piper mullesua Buch. -Ham.

Description: General colour shiny black; antennae piceous, except segments 2–5, which are light brown to piceous; fore- and midfemora piceous, hind femur black, with apex tainted brown ventrally; all tibiae and tarsi dark brown.

Supraorbital sulcus indistinct. The antennae do not extend beyond half of the elytra over the pronotum. Third antennomere distinctly shorter than fourth, fourth slightly longer than fifth; fifth and sixth each shorter than preceding antennomere; seventh to ninth subequal, each longer than sixth; tenth slightly shorter than ninth; last subequal to first; last four or five antennomeres slightly thickened; the antennae reach half of the elytra over the pronotum.

Pronotum with antebasal transverse impression, and with punctures in the antebasal transverse impression stronger than those on the rest of the pronotum. Apex of intercoxal prosternal process nearly straight, with a pair of preapical depressions: in some specimens these depressions join to form a transverse depression. Prosternal intercoxal process 2.0 times wider than the distance between the anterior margin of the prosternum and the coxal cavity; distance from the anterior margin of the prosternum to the end of the intercoxal prosternal process 4.3 times the minimum width of the prosternal intercoxal process.

Mesoscutellum as broad as long, with an acute apex. Mesosternum depressed on top, with a nearly straight posterior margin. Elytra with maximum width at posterior two-thirds. Elytral apex concave near sutural margin, broad. Elytral punctures do not form rows, are moderately strong, with the distance between adjacent punctures 0.5–2.5 times the diameter of a puncture in the anterior half of the elytron. First metatarsomere slightly longer than half of the metatibia.

Subparallel ridges on first abdominal ventrite poorly developed, evidenced by rows of setae reaching the middle of the ventrite, and with rows of setae parallel with each other ( Fig. 81 ). Posterior margin of lobe in middle of last male ventrite apparently convex ( Fig. 82 ).

In lateral view, aedeagus nearly straight in distal two-thirds, with obtuse apex ( Fig. 84 ); unusual in ventral view, being bifid at apex, ventral side convex with a longitudinal depression along apex ( Fig. 83 ); distal opening completely covered with lamina ( Fig. 85 ); arm of tegmen shorter than stem ( Fig. 86 ).

Spermatheca with horizontal part of pump subequal to vertical part; receptacle about 3.5 times longer than wide, with the outer side slightly concave at a distance of one-third of receptacle from the origin of the duct, inner side convex, narrowing towards duct; duct with multiple coils ( Fig. 87 ). Vaginal palpus narrowed near middle; distal sclerotization subequal to proximal sclerotization, and with each being subequal to the lateral membranous area ( Fig. 88 ). Distal sclerotization of tignum arrow-head shaped, and longer than wide ( Fig. 89 ).

Sexual dimorphism: First pro- and mesotarsomeres slightly enlarged in males compared with females. Mesotibia in lateral view distinctly curved and enlarged distally in males ( Fig. 79 ), straight and not enlarged distally in females ( Fig. 80 ). First metatarsomere of males unmodified.

Measurements (n = 4): Length, 1.97–2.35 (2.18); width, 1.06–1.22 (1.15); length of pronotum, 0.43–0.51 (0.47); width of pronotum, 0.66–0.74 (0.70); width of head across eyes, 0.52–0.58 (0.56); transverse diameter of one eye, 0.20–0.21 (0.21); distance between eyes, 0.22–0.27 (0.25); distance between eye and antennal socket, 0.02–0.04 (0.03); distance between antennal sockets, 0.06–0.07 (0.06); diameter of one antennal socket, 0.06–0.08 (0.07); length of aedeagus, 0.95; length of receptacle, 0.26; length of vaginal palpus, 0.42.

Types: Holotype ♂. Labels: (1) India, Tamil Nadu, Naduvattam , 26 October 1998, coll. K. D. Prathapan; (2) Tegyrius nigrotibialis sp. nov. Prathapan & Viraktamath, 2007; (3) holotype ( BMNH).

Paratypes (22 specimens): 1♂ and 2♀, with the same data as for the holotype ; 6♂ and 5♀, with the same data as for the holotype, except that the date was 19 October 2003 ; 5♂ and 3♀, South India, Western Ghats, Tamil Nadu, Naduvattam, 27 June

2004, 11°28′24.2″N, 76°33′04″E coll. K. D. Prathapan (4 BMNH, 2 EUJ, 2 KUJ, 2 LMC, 2 NHMB, 2 NPC, 4 PKDC, 2 UASB, and 2 USNM) .

Etymology: The name nigrotibialis refers to the black colour of the beetle, and the modified mesotibia.

Remarks: Tegyrius nigrotibialis sp. nov. can be distinguished from all other black species of Tegyrius by the sexually dimorphic mesotibia, as well as by the apically bifid aedeagus.

Figures

Figures 79–89. Tegyrius nigrotibialis sp. nov.: 79, mesotibia of male, lateral view; 80, mesotibia of female, lateral view; 81, intercoxal ridges on first abdominal ventrite; 82, male last abdominal ventrite; 83, aedeagus, ventral view; 84, aedeagus, lateral view; 85, distal opening; 86, tegmen; 87, spermatheca; 88, vaginal palpi; 89, tignum.