Cycadophila (Strobilophila) yangi 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 : 58-60

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

Figs. 2 G, 21A–E

Adult diagnosis. A member of Cycadophila (Strobilophila) as discussed above, readily distinguished from the other members of the subgenus by the narrowed protibia bearing widely spaced teeth along the apical half of the lateral margin, lacking or having a greatly reduced furrow on each side of the pronotal base, entire elytral disc with short setae, and lacking notable sexual dimorphism.

Adult description. Length 3.60–4.40 mm; width 1.4 0–1.68 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; dorsal surface distinctly punctate, surface appearing slightly dulled, dorsally appearing glabrous, with short procumbent hairs associated with punctation behind eyes and covering surface and declivity of elytra (best seen in profile), ventrally mostly covered with short procumbent setae.

Head in dorsal view conical, gradually narrowed apically, surface flat to slightly convex, distinctly punctured; width 0.71–0.88 mm; dorsal interocular distance 0.45–0.59 mm, head width/dorsal interocular distance ratio 1.49– 1.58, ventral interocular distance 0.38–0.47 mm, head width/ventral interocular distance ratio 1.86–1.87. 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 3/4 pronotal width, and slightly longer than head width, antennomere relative lengths from base to end approximately 19:14:13:10:10:10:10:11:15:15:16; 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, with small 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– 0.66, convex, nearly parallel-sided; 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 or without an indistinct short longitudinal furrow posterolaterally, beginning at pore on posterior margin, extending forward and ending abruptly, when present length of furrows relative to pronotal length ±0.13. 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 3.23–3.24, greatest width near midlength; with marginal bead basally, scutellary striole with 7–9 punctures; intervals of striae with distinct punctures. All elytral punctures bearing a single short seta; seta length less than interpuncture distance. Punctation on meso- and metaventrite distinct. Metaventrite long, convex laterally, slightly impressed medially, metathoracic discrimen extending slightly over half metaventrite length. Legs stout, similar in length; femora compressed laterally; tibiae shorter than femora, gradually dilated to narrow apex. Protibia narrowly dilated at apex, apex and apical 1/2 of lateral margin with stout spinules, marginal spinules separated by distance equal to their length. Meso- and metatibia slightly less dilated distally.

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; ventrite I lacking subcoxal line, slightly longer medially than II; I–IV each possibly lacking a 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.

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 2.20. Aedeagus with median lobe elongate, slender, highly sclerotized, apex long and acuminate. Ratio of median lobe length to penile strut length 1:3. Female similar to male, except with pygidium truncate, not as well developed.

Type locality. Thailand: Chaiyaphum, Sai Thong Nat. Park, 15°53.835'N, 101°27.260'E.

Range. Thailand (Chaiyaphum, Chiang Mai, Kanchanaburi, Prachuap Khiri Khan).

Material examined. Holotype (by designation) male with the following labels:1) [rectangular; white; printed in black ink] “ THAILAND, [Prachuap Khiri Khan] Pran Buri near Kao Sam Roi Yot N. P., 12°07'N, 99°57'E , 23 Apr. 1996, W. Tang, ex ♂ strobilus of Cycas pranburiensis (WT 18)”; 2) [rectangular; red; printed in black ink] “ HOLOTYPE ♂ Cycadophila yangi P. Skelley, G. Xu & W. Tang 2017 ”. Deposited in the FSCA . Allotype and 11 paratypes: THAILAND: [Chiang Mai] SW of Fang , 19°38'N, 99°07'E, 640m , 7 Feb. 1995, W. Tang, S.- L. Yang, P. Vatcharakorn, ex pollen-shedding ♂ strobilus of Cycas pectinata in disturbed forest on limestone soil, SLY 690 (4); Kanchanaburi Prov., near Thon Pha Phum, 14°53'N, 98°49'E, 700m , 11 Feb. 1995, W. Tang, S.- L. Yang, P. Vatcharakorn, ex pollen-shedding ♂ strobilus of Cycas pectinata in disturbed forest, SLY 707 (1); [Prachuap Khiri Khan] Pran Buri near Kao Sam Roi Yot N. P., 12°07'N, 99°57'E , 23 Apr. 1996, W. Tang, ex ♂ strobilus of Cycas pranburiensis (WT 18) (holotype, FSCA; allotype, ANIC; 6). Paratypes deposited at ANIC, FSCA.

Etymology. In honor of George (Si-Lin) Yang, founder and president of Seq-Gen, co-collector of type specimens of this species and many other specimens used in this study and for his financial support of this research.

Remarks. Adults of Cycadophila (S.) yangi were collected together with those of C. (S.) tansachai in cones of Cycas pectinata in Thailand indicating that adults of these two species of subgenus Strobilophila may coinhabit a single male cone. A larval morphotype has been identified from these cones and the DNA of the 16S rRNA gene was analyzed for two individuals of this larval morphotype. The DNA sequence of one larval individual matched that of adult C. (S.) tansachai . The other larva exhibited a DNA sequence substantially different from that of adults of three other Strobilophila species examined (see sample D0333 in Fig. 1 ). Preservation of adult C. (S.) yangi available for study was insufficient for DNA analysis so we cannot match this unknown larva to C. (S.) yangi , however, it is likely the unmatched larva is C. (S.) yangi . Xu et al. (2015) demonstrated that adults of up to four species of subgenus Cycadophila and up to two species of larva may coinhabit a single Cycas cone. Similarly, adults of two species of subgenus Strobilophila may inhabit the same cones and two species are feeding and producing larvae within the same cones. There is no evidence that a third species of Strobilophila may be involved. Our current DNA analysis suggests that C. (S.) yangi may not belong within Strobilophila, but may be better placed in a separate clade. However, until stronger genetic evidence is available, we rely on morphological characters in assigning this species within Strobilophila.

Figures

FIGURE 1. Phylogenetic tree based on maximum likelihood analysis of 16 S rRNA gene sequences of four species of New World Pharaxonotha and ten species of Asian Cycadophila. Scale bar indicates base pair substitutions per nucleotide position; numbers on the branches of the trees are bootstrap values.

FIGURE 2. Key characters of adults: photographs of lateral head and pronotal margin: A) Cycadophila (C.) fupingensis; B) C. (Strobilophila) tansachai; C) C. (C.) yunnanensis; SEM of protibia, ventral view: D) C. (C.) fupingensis; E) C. (C.) debaonica; F) C. (S.) tansachai; G) C. (S.) yangi; photographs of mesotibia, ventral view: H) C. (C.) debaonica female; I) C. (C.) debaonica male; J) C. (C.) lata male; photographs of left half of pronotum: K) C. (C.) collina; L) C. (C.) debaonica; M) C. (S.) kwaiensis; N) C. (S.) tansachai; photographs of mesofemur of major male: O) C. (C.) collina ex Vietnam; P) C. (C.) debaonica.