Cycadophila (Strobilophila) 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 : 45-48

Cycadophila (Strobilophila) Skelley, Xu & Tang , new subgenus

Type species. Cycadophila (Strobilophila) tansachai , n. sp., here designated.

Adult diagnosis. The subgenus C. (Strobilophila) is easily distinguished from other members of the genus by the pronotal lateral carina flat and thickened in lateral view with punctation scattered on carinal surface, by the presence of stout setae on the lateral margin of the protibia and sexual dimorphism, when present, on abdominal ventrite V, not legs as in other groups.

Adult description. Length 3.60–6.40 mm, width 1.40–2.40mm. Body: form elongate, not strongly parallel sided; dorsoventrally flattened to weakly convex; widest at middle of elytra; color reddish-brown without color pattern; dorsal punctation moderately coarse, evenly distributed, dense. Head: dorsal surface of head relatively flat; convex between eyes, clypeus flat apically; some with vague depressions near base of clypeus; clypeus truncate anteriorly; supraocular stria extending about 3/4 of length of eye from posterior end; transverse occipital ridge present; stridulatory file on occipital region of head present, one on each side, widely separated, parallel; eye prominent, coarsely faceted; lacking lateral temple behind eye. Mouthparts: mentum with large triangular base defined by carina; lateral pockets in front of carina small or indistinct; submentum and gula relatively flat, suture not obvious, medially with transverse, anteriorly concave depression with row of setose punctures. Pronotum: pronotal anterior marginal bead complete, fine; pronotal anterior margin near eyes emarginate, anterior angles rounded; surface near anterior angle convex; pronotal basal pits present, associated longitudinal groove present or not, groove up to 1/4 pronotal length; secondary transverse groove between pits present, broad, curving along posterior margin except medially where slightly separated from margin; pronotal lateral carina evenly arcuate, lacking modifications; pronotal lateral carinal bead thin in dorsal view; in lateral view thickening anteriorly, surface flattened laterally, appearing double edged. Scutellar shield broadly pentagonal. Elytra with coarse, dense interval punctures. Prosternum: pronotal hypomeron with longitudinal striations, weak in some. Legs: protibia dilated distally, angled laterally but without apical tooth; disto-ventral margin with fringe of stout ventrally directed, tooth-like spinules, some present on apical-lateral margin; meso- and metafemora elongate oval, meso and metatibiae moderately angularly dilated at apex. Abdomen: ventrites I–IV lacking pair of erect sensory hairs located on either side of the middle. Sexual dimorphism: not evident on legs. Male genitalia: median lobe and tegmen flattened laterally, weakly twisted basally; penile struts not fused, separate entire length, each 5.00–6. 0 0× longer than median lobe; flagellum shorter than penile strut, not coiled; spiculum gastrale asymmetrical. Female genitalia: gonocoxites triangular, gradually narrowed posteriorly; apices of gonocoxites laterally with concave impression and setae. Gonostylus small, inserted at the concave impression of the gonocoxite, with several short setae and 1 long seta. Valvifers expanded posteriorly. Spermatheca elongated, C-shaped.

Larva. Description based on a larval morphotype found with adults of Cycadophila (Strobilophila) tansachai in Cycas elephantipes male cones. 16S rRNA gene sequences from one individual of this larval morphotype from this host match those of adult C. (S.) tansachai , but a second sample of this larval morphotype from Cycas pectinata did not match any sampled adults of subgenus Strobilophila. This second larva may correspond with C. (S.) yangi adults, which have been collected together with adults of C. (S.) tansachai in Cycas pectinata . For further discussion, see paragraph prior to larval key and description of C. (S.) yangi below.

Individuals up to 7.00 mm; body elongate, in dorsal view sides subparallel and narrowing anteriorly and posteriorly, cylindrical, lightly pigmented except for head and sections of tergum ( Figs. 15 A–B). Head: sclerotized, dark brown with faint pattern of reticulation, smooth without ornamentation, protracted, prognathous and slightly flattened; epicranial stem absent, frontal arms lyriform and contiguous basally; median epicranial suture distinct, extending half the length of the frontal arms; 5 stemmata on each side; antenna length approximately half of midlength of head, 3-segmented, antennomere I slightly shorter than wide, II more than 3 times as long as I, III slightly longer than I; frontoclypeal suture absent; labrum free. Mandibles symmetrical, incisor cleft with dorsal prong shorter than ventral prong, both prongs smooth; mola well-developed, asperate with asperites forming transverse rows; accessory ventral process present; prostheca hyaline, with single edge, broad basally, triangular with angulate apex ( Fig. 15 F). Ventral mouthparts retracted, with well-developed maxillary articulating area; maxilla with transverse cardo, elongate stipes, 3-segmented palp, terminal palpomere>3× its own width, mala falciform with apex divided into 3 lobes; labium more or less free to base of mentum, labial palps 2-segmented, separated by 1.50× width of basal palpomere ( Fig. 15 G), distal palpomere length 2.00× its own width. Hypostomal rods diverging; ventral epicranial ridges weakly developed. Thorax and abdomen: dorsal surface: anterior 1/2 of T2–3 and A1–A7, anterior 3/4 of A8, central 1/2 of T1 and all of A9 pigmented dark brown, sclerotized; brown areas, except for anterior 1/4–1/3, more or less randomly covered with granules; sclerotized regions of T1–3 and A1–8 distinctly bisected by light-colored middorsal line; T2–3 and A1–8 with transverse row of 5–6 pairs of large tubercules along posterior margin and transverse row of 3–4 pairs of large tubercles 1/3 of length from anterior margin; tubercles appearing light colored and contrasting against dark background, setiferous; A9 tergum with pair of urogomphi; urogomphi covered with granules basally, dorsal and lateral sides of base with 3 pairs of prominent setiferous tubercles, in dorsal view tubercles form approximately semicircular pattern, pair of tubercles closest to midline just anterior to urogomphi (labeled t 1 in Figs. 15 C–D) with hook at apex, base of this pair angled vertically, apical hook shaped like a bird head and neck with bill pointing posteriad ( Figs. 15 A, C), top of bird head with a prominence with a single setae; bird beak length about 2.00× its own vertical width, without sharply curved tip; urogomphi length from basal tubercle t3 (see Fig. 15 D) to apex approximately 1.00× length of remainder of segment, apical 1/3 of length smooth without tubercles. Legs 5-segmented; coxae moderately widely separated, procoxae separated by>1.00× coxal width; meso- and metacoxae each separated by>2.00× coxal width ( Fig. 15 E). Spiracles raised, annular-biforous.

Etymology. An intentional combination of the plant structure name ‘strobili’, with the Greek -phil-, having a strong affinity or love. The name is feminine in gender.

Remarks. Strobilophila is distinct among the cycad inhabiting erotylids by the strongly dilated protibia fringed with stout spinules apically and the thickened lateral pronotal carina. In size and superficial characters, Strobilophila resembles Xenocryptus tenebrionoides Arrow which inhabits cycads in Australia and has been cited as “ Xenocryptus ” in Tang et al. (1999). However, the genus Xenocryptus has internal abdominal calli, symmetrical male genitalia, and belongs in the Xenocryptinae ( Leschen 2003). The distinction between the Pharaxonothinae and the Xenocryptinae is tenuous and in need of further study ( Xu et al. 2015). This must be done considering all known taxa of these subfamilies, including other problematic and undescribed taxa that are cycad associates.

Figures

FIGURE 15. Photographs of Cycadophila (Strobilophila) larvae: A – B) lateral and dorsal habitus; C – D) terminal segments of abdomen, dorsal and lateral views; E) head and prothorax, ventral view; F) right mandible, dissected, ventral view; G) maxillary palp, mala and labial palps, dissected, ventral view.