Cycadophila (Strobilophila) assamensis Skelley, Xu & Tang

Skelley, Paul, Xu, Guang, Tang, William, Lindström, Anders J., Marler, Thomas, Khuraijam, Jibankumar Singh, Singh, Rita & Rich, Stephen, 2017, Review of Cycadophila Xu, Tang & Skelley (Coleoptera: Erotylidae: Pharaxonothinae) inhabiting Cycas (Cycadaceae) in Asia, with descriptions of a new subgenus and thirteen new species, Zootaxa 4267 (1), pp. 1-63 : 48-50

Cycadophila (Strobilophila) assamensis Skelley, Xu & Tang , new species

Figs. 16 A–G

Adult diagnosis. A member of Cycadophila (Strobilophila) as discussed above, more readily distinguished by a combination of characters than any single unique character, and by analysis of the 16S rRNA mitochondrial gene. Cycadophila assamensis can be distinguished by the distally dilated protibia bearing narrowly spaced teeth along the apical third of the lateral margin, the distinct furrow on each side of pronotal base, elytral disc being mostly glabrous, the nearly straight basal pronotal margin, the lateral pronotal carina being abruptly curved inward at posterior angle pore which has a small acute projection behind it, and the terminal abdominal ventrite being sexually dimorphic (males with surface evenly coarsely punctate and setose; females with surface entirely setose and bearing a glossy area near the medial apex).

Adult description. Length 4.69–5.19 mm; width 1.8 8–2.00 mm. Body in dorsal view elongate, sides nearly straight, greatest width at middle of elytra; in lateral view convex dorsally. General body and appendage color solid reddish-brown [available specimens poorly preserved, darker; image of fresh specimen has color identical to C. tansachai ]; dorsal surface distinctly punctate, surface appearing slightly dulled, dorsally appearing glabrous, with short procumbent hairs associated with punctation, ventrally mostly covered with short procumbent setae.

Head in dorsal view conical, gradually narrowed apically, surface flat to slightly convex, distinctly punctured; width 1.00– 1.10 mm; dorsal interocular distance 0.66–0.73 mm, head width/dorsal interocular distance ratio 1.50– 1.52; ventral interocular distance 0.46–0.49 mm, head width/ventral interocular distance ratio 2.16–2.25. Eye globular; bordered dorsally with supraocular stria; projected laterally, with large black facets and short, inconspicuous interfacetal setae. Frons with short, dark, subcuticular suture on each side, approximately 1/4 width of frons in length, extending obliquely to lateral margin above and anterior to antennal insertion. Antennal length about 2/3 pronotal width, and slightly longer than head width, antennomere relative lengths from base to end approximately 19:13:13:10:10:10:10:10:15:15:19; antennomere I (scape) fairly large, slightly elongate, antennomere II slightly smaller than III; IV–VIII small, width equals length; club fairly large, IX–XI similar in length, XI globular. Clypeus truncate anteriorly, anterior margin with long setae; densely punctate; somewhat emarginate, with narrow margin. Maxillary palpomeres II, III slightly longer than wide; IV elongate oval, apex densely papillate; relative lengths of II–IV approximately 3:3:5. Labium with mentum pentagonal with carina forming triangular plate projecting medially, lacking distinct lateral pockets; labial palpomere III elongate-oval. Mentum and submentum with moderate punctation and setation, setae short. Gular area smooth, without setae or punctation, except near suture with submentum where a shallow transversely elongate fovea is present bearing dense setose punctures, fovea dark brown.

Thorax with pronotum transverse in dorsal view, with marginal beads on all sides; length/width ratio 0.65– 0.68, convex, evenly weakly arcuate most of length; anterior angles rounded; lateral carina with thickened bead, bead bearing scattered setose punctures; posterior angle exteriorly angulate, indented at pore; posterior margin projecting medially; with narrow, short longitudinal furrow posterolaterally, beginning at pore on posterior margin, extending forward and ending abruptly, length of furrows relative to pronotal length 0.22–0.24. Prosternum with anterior margin slightly emarginate, finely denticulate with fringe of long, anteriorly directed setae; posterior prosternal process round and convex. Hypomeron with coarse punctures laterally, medially with longitudinal striations. Scutellar shield transverse, posterior margin projected, pentagonal. Elytra elongate, nearly parallel sided, convex; length/width 3.28–3.65, greatest width near midlength; with marginal bead basally, striae not impressed, scutellary striole with 10–12 punctures; intervals of striae with distinct punctures. All elytral punctures bearing a single short seta; seta visible but barely emerging out of puncture. Punctation on meso- and metaventrite distinct.

Metaventrite long, convex laterally, slightly impressed medially, metathoracic discrimen extending about ¾ metaventrite length. Legs stout, similar in length; femora compressed laterally; tibiae shorter than femora, dilated to wide apex. Protibia triangularly dilated at apex, apex and apical 1/3 of lateral margin with stout spinules, marginal spinules separated by less than length. Meso- and metatibia less triangularly dilated.

Abdomen with 5 ventrites bearing fine punctures; anterior margin with intercoxal process narrow, with triangular point anteromedially, lateral edges slightly projected, lateral and posterior margins arcuate, converging posteriorly; anterior and posterior margins of ventrites more or less straight or weakly bisinuate ( Figs. 16 F–G); ventrite I lacking subcoxal line, slightly longer medially than II; I–IV each with pair short hairs located adjacent to midline (often abraded); II–IV subequal in length; V slightly longer than IV with lateral margins converging posteriorly to a rounded apex bearing row of short appressed, densely arranged setae; ventrite V surface of male evenly coarsely and rugosely punctate, and entirely setose (similar to C. tansachai in Fig. 19 F), female evenly setose, basally with coarse punctures, with small area of fine punctures and glossy surface near medial apex ( Fig. 16 G).

Male genitalia (tegmen and median lobe of aedeagus) twisted approximately 45° toward the left side of animal and resting on side. Tegmen sclerotized, triangular, gently twisted; with anterior region ring-like, posterior region sheath-like, posterior margin slightly arcuate; lateral margins gradually converging posteriorly; dorsally with 2 large, elongate, somewhat coniform parameres. Parameres with long setae apically; length/width ratio 2.2 0. Aedeagus with median lobe short, slender, highly sclerotized, apex long and acuminate. Ratio of median lobe length to penile strut length 1:5. Female similar to male; except with pygidium truncate not as well developed; and dimorphic abdominal ventrite V surface as noted above.

Type locality. India: Assam, Kamrup, North Guwahati.

Range. India (Assam, Bihar).

Material examined. Holotype (by designation) female with the following labels: 1) [rectangular; white; printed in black ink] “ INDIA: Assam, Kamrup, North Guwahati , ex ♂ cone Cycas pectinata, 2008 , K. J. Singh ”; 2) [rectangular; pink; printed in bold black ink] “ PHOTO ” . 3) [rectangular; white; printed in black ink] “collection date June-July 2007”; 4) [rectangular; white; hand written in black ink] “ INDIA: ASSAM, Kamrup, North Guwahati , Cycas pectinata , NG1”; 5) [rectangular; red; printed in black ink] “ HOLOTYPE ♂ Cycadophila assamensis P. Skelley, G. Xu & W. Tang 2017 ”. Deposited in the FSCA . Allotype male and 3 paratypes: same data as holotype (holotype & allotype, FSCA, 1); INDIA: Assam, Guwahati IIT Campus, ex ♂ cone Cycas pectinata, 2008 , K. J. Singh (2). Deposited in the FSCA . Others examined: One additional adult male collected in association with larvae, currently considered this species: INDIA: Bihar, West Champaran , Valmiki Nat. Park, Mar 2015, K. J. Singh (1). Deposited in FSCA .

Etymology. Named for the State where the type specimens were collected.

Remarks. A female holotype was chosen because it was the most intact specimen available for study and because it shows the sexual dimorphism used to distinguish the species. Cycadophila assamensis is most similar to C. tansachai , differing most notably in abdominal sexual dimorphism.

Paucity of Indian materials prevents us from performing certain analyses and answering certain questions. Adult morphology allow us to distinguish the populations from India and propose a name for future research. Larvae from Bihar are also morphologically distinguishable from C. (Strobilophila) larvae collected in Thailand by the posteriad-tilting orientation of their t1 tubercle (see Key to larvae above) vs. the vertically oriented t1 turbercle in Thai specimens. While the Assam and Bihar populations are presented here as conspecific, we have doubts requiring further analyses. Thus, the type series is limited to the Assam population where we are able to make morphological comparisons with all known species. As noted above, molecular analyses failed with available material.

The host for this species in Assam, Cycas pectinata , occurs at atypically low elevations for the species (52–192 m; see Singh & Singh 2014) vs. over 500 m for other localities of Cycas pectinata in the states of Manipur and West Bengal, India or in Thailand and provides evidence that this beetle is geographically isolated from other populations of the Strobilophila complex. See also remarks under C. kwaiensis .

Figures

FIGURE 16. Photographs of Cycadophila (Strobilophila) assamensis, female holotype: A) dorsal habitus; B) ventral habitus; C) lateral habitus; D) head and prosternum, ventral; E) male genitalia; F) male paratype, abdominal ventrite V; G) female holotype, abdominal ventrite V.

FIGURE 19. Photographs of Cycadophila (Strobilophila) tansachai, paratypes: A) dorsal habitus; B) ventral habitus; C) lateral habitus; D) head and prosternum, ventral; E) male genitalia; F) male abdominal ventrite V; G) female abdominal ventrite V; H – I) inflated endophallus, lateral and ventral views.