Tegyrius dalei, 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 : 339-341

TEGYRIUS DALEI SP. NOV. ( FIGS 41–49 )

Distribution: India (Kerala).

Host plant: Piper trioicum Roxb. Description: General colour black. Antennae, mouthparts, tibiae, and tarsi pitch brown to black.

Supraorbital sulcus indistinct. Third antennomere shorter than fourth; fourth and fifth subequal; sixth apparently shorter than fifth; seventh apparently longer than sixth; eighth shorter than seventh; eighth to tenth each apparently shorter than preceding segment; first and last subequal; last six antennomeres slightly thickened; antennae not extending beyond half of the elytra over the pronotum.

Pronotum with antebasal transverse impression, with punctures in the antebasal transverse impression being stronger than those on the rest of the pronotum. Apex of prosternal intercoxal process convex, with preapical depressions that may be indistinct in some specimens. Prosternal intercoxal process 2.2 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 2.3 times the minimum width of the prosternal intercoxal process.

Mesoscutellum broader than long, with broad apex. Mesosternum depressed on top, with slightly concave posterior margin. Elytra with maximum width at anterior two-fifths; elytral apex convex and moderately broad; elytral punctures forming uncountable rows, moderately bold, with the distance between the adjacent punctures in the anterior half of the elytron 0.5–2.5 times the diameter of a puncture. First metatarsomere slightly longer than half of the metatibia.

Subparallel ridges on first abdominal ventrite reach the middle of the ventrite, and converge distally ( Fig. 41 ). Last female tergite with short, indistinct groove along the middle. Lobe in the middle of the last ventrite of males with convex distal margin ( Fig. 42 ).

Distal two-thirds of the aedeagus nearly straight in lateral view, with an acute apex ( Fig. 44 ). In ventral view with acute, wedge-like preapical longitudinal ridge; distal end tridentate ( Fig. 43 ); distal opening partially covered with lamina ( Fig. 45 ); arms of tegmen shorter than stem ( Fig. 46 ).

Spermatheca with horizontal part of pump subequal to vertical part; receptacle about three times longer than wide, outer side convex, inner side apparently convex, and not appreciably tapering towards the duct; duct with a knot at the base ( Fig. 47 ). Vaginal palpus with lateral unsclerotized area, longer than proximal or distal sclerotization, and with proximal sclerotization subequal to distal sclerotization ( Fig. 48 ). Tignum with arrow-shaped distal sclerotization ( Fig. 49 ).

Sexual dimorphism: First pro- and mesotarsomeres slightly enlarged in males compared with females. Mesotibia and first metatarsomere of males unmodified.

Measurements (n = 4): Length, 1.58–2.02 (1.80); width, 0.90–1.08 (0.97); length of pronotum, 0.40–0.47 (0.43); width of pronotum, 0.58–0.68 (0.62); width of head across eyes, 0.47–0.52 (0.49); transverse diameter of one eye, 0.17–0.20 (0.18); distance between eyes, 0.19–0.22 (0.2); distance between eye and antennal socket, 0.02 (0.02); distance between antennal sockets, 0.06–0.07 (0.06); diameter of one antennal socket, 0.06 (0.06); length of aedeagus, 0.76; length of receptacle, 0.22; length of vaginal palpus, 0.39.

Types: Holotype ♂. Labels: (1) India, Kerala, Ponmudi , March 2003, coll. K. D. Prathapan; (2) Tegyrius dalei sp. nov. Prathapan & Viraktamath, 2007; (3) holotype ( BMNH).

Paratypes (79 specimens): 6♂ and 7♀, with the same data as for the holotype; 1♂ and 1♀, with the same data as for the holotype, except that the date was 29 February 2002; 7♂ and 5♀, with the same data as for the holotype, except that the date was 4 August 2002; 1♀, with the same data as for the holotype, except that the date was 29 September 2002; 2♂ and 1♀, with the same data as for the holotype, except that the date was 17 August 2003; 11♂ and 2♀, Tvm-Kallar, 8 April 1999; 1♀, with the same data, except that the date was 2 September 1999; 3♂, Ponmudi-Kallar, 20 March 2005; 2♀, Arippa, 8 February 2004; 6♂ and 3♀, with the same data, except that the date was 2 June 2005; 1♂ and 4♀, Neyyar WLS, 12 February 2004; 2♂ and 1♀, Sasthamnada, 14 February 2004; 2♂, Periyar Tiger Reserve, 15 February2004; 1♂, Palaruvi, 22 June 2006; 6♂ and 2♀, Pampa, 28 June 2006, from Piper hapnium Ham. (10 BMNH, 4 EUJ, 4 KUJ, 4 LMC, 10 NHMB, 10 NPC, 19 PKDC, 4 UASB, and 10 USNM). spermatheca, aedeagus, and the last visible ventrite of males are unusually similar in both of the species. Tegyrius dalei sp. nov. is confined to the extreme south of the Western Ghats, and never occurs north of the Palghat Gap, whereas T. tippui sp. nov. occurs only north of the Palghat Gap. The Palghat Gap is a break in the Western Ghats mountain range of about 26 km, and there is no significant difference in the climate between the mountains north and south of the gap. Yet the gap has a significant sway on the distribution of the biota on either side of it ( Bhimachar, 1945). This is yet another lucid illustration of the influence of the Palghat Gap on speciation and the zoogeography of the Western Ghats.

Figures

Figures 41–46. Tegyrius dalei sp. nov.: 41, intercoxal ridges on first abdominal ventrite; 42, male last abdominal ventrite; 43, aedeagus, ventral view; 44, aedeagus, lateral view; 45, distal opening; 46, tegmen; 43b, aedeagus of Tegyrius tippui sp. nov., apex in ventral view.

Figures 47–49. Tegyrius dalei sp. nov.: 47, spermatheca; 48, vaginal palpi; 49, tignum.