Cycadophila debaonica Xu, Tang & Skelley

Xu, Guang, Tang, William, Skelley, Paul, Liu, Nian & Rich, Stephen, 2015, Cycadophila, a new genus (Coleoptera: Erotylidae: Pharaxonothinae) inhabiting Cycas debaoensis (Cycadaceae) in Asia, Zootaxa 3986 (3), pp. 251-278 : 257-262

Cycadophila debaonica Xu, Tang & Skelley , new species

( Figures 2–4 )

Adult diagnosis. Distinguished from other Cycadophila spp. by the long supraocular striae, head width/ventral interocular distance ratio <3.5; width of elytra greatest at middle, and degree of distal dilation of tibia.

Adult male description. Length 3.86–5.27 mm, width 1.70–2.31 mm. Body in dorsal view elongate-oval, greatest width at middle of elytra; in lateral view convex dorsally. General body color reddish-brown ( Figs. 2 A–D), head darker than pronotum and lateral halves of elytra; elytra with large central black maculation near medial margin occupying roughly half of elytral length from near the scutellum to 2/3 length of elytra and roughly 2/5 of the elytral width, dorsal surface punctate, shining and dorsally appearing glabrous, short procumbent hairs associated with punctation behind eyes and along lateral sides and declivity of elytra, ventrally mostly covered with short procumbent setae.

Head in dorsal view conical, gradually narrowed anteriorly, surface flat to slightly convex, finely, sparsely punctured ( Figs. 3 A, C); width 0.89–1.16 mm; dorsal interocular distance 0.48–0.70 mm, head width/dorsal interocular distance ratio 1.42–1.91, ventral interocular distance 0.30–0.41 mm, head width/ventral interocular distance ratio 2.92–3.13. Eye globular; bordered dorsally with long supraocular stria reaching anterior angle of eye; 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 anterior to antennal insertion. Antennal length slightly shorter than pronotal width, slightly longer than head width, antennomere relative lengths approximately 18:12:13:10:10:10:10:10:14:14:21; antennomere I (scape) fairly large, slightly elongate, antennomere II slightly smaller than III; IV–VIII small, width equals length; club fairly large, IX and X similar in length, XI slightly longer, globular. Clypeus truncate anteriorly, anterior margin with long setae; densely punctate; somewhat emarginate, with narrow margin. Mandible with 3 apical teeth; prostheca extending from mola halfway to apical teeth, length about ½ width, edge nearly straight, with fringe of hair along dorsal base that extends to the proximal apical tooth; mola with carinulation and small spines. Labrum transverse, about 2 times broader than long; anterior margin fringed with long bristles, especially dense medially. Hypopharynx with thin setae directed medially. Maxilla with cardo expanded apically; stipes narrowly triangular, apically acute, partially overlapping with palpiger; galea and lacinia with long, densely aligned setae; setae on the lacinia thick and strong, but distinguishable hooks absent from surrounding dense setae; galea wider than lacinia. Maxillary palp 4- segmented, palpomere I very small; II, III and IV longer than width; IV elongate oval, apex densely papillate; relative lengths of II-IV approximately 4:3:7. Labium with mentum pentagonal with carina forming triangular plate projecting medially, lacking distinct lateral pockets; labial palp 3-segmented; palpomere I small, elongate; II transverse; III large, 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 shallow transversely elongate fovea are present bearing dense setose punctures ( Fig. 3 D), fovea dark brown.

Thorax with pronotum transverse in dorsal view with marginal beads on all sides; length/width ratio 0.60–0.69, convex, wider at base; anterior angles weakly developed; posterior angles exteriorly angulate; posterior margin projecting medially; with a narrow longitudinal furrow posterolaterally, beginning at pore on posterior margin extending forward and ending abruptly, length of furrows relative to pronotal length 0.16–0.19. Prosternum in ventral view convex; anterior margin slightly emarginate, finely denticulate with row of long, anteriorly directed setae; prosternal process round and convex apically. Hypomeron laterally with few punctures, medially without longitudinal striations. Scutellar shield transverse, posterior margin clearly projected, pentagonal. Elytra in dorsal view elongate-oval, convex; length/width 2.7–3.3, greatest width near midlength; with marginal line basally, 10 complete striae of moderate puncture size, scutellary striole extending ¼ elytral length, with 10–13 punctures; intervals of striae with fine, shallow punctures. All punctures of elytral striae bearing a single short seta; seta only visible in profile, extending slightly out of puncture. Punctation on meso- and metaventrites shallow, small. Metaventrite long, convex laterally, slightly impressed medially, metathoracic discrimen extending slightly over half metaventrite length. Legs stout, relatively similar in length and shape. Procoxa oval; mesocoxa globular; metacoxa transversely elongate-oval; trochanters obliquely truncate apically; femora compressed laterally; tibiae shorter than femora, gradually dilated to narrow apex; protibia distinctly dilated apically, with apical fringe of short, stout spinules ventrally, inner margin with fine setae ( Fig. 3 E).

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 with pair of long erect sensory 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 90˚ toward the left side of the animal and resting on side ( Fig. 2 E). Tegmen sclerotized, triangular, but twisted medially; 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-shaped parameres. Parameres apically with long setae; length/width ratio 2.6. Aedeagus with median lobe slender, highly sclerotized, apex long and acuminate. Ratio of penile strut length to median lobe length 3:1.

Female similar to male except with protibia less dilated apically, mesotibia slightly less robust than in male, pygidium truncate, apical edge fairly straight with 7 long setae and a fringe of setae about 1/2 as long. Genitalia with gonocoxites triangular, gradually narrowing posteriorly; apices of gonocoxites laterally with concave impression and setae. Gonostylus inserted at the concave impression of the gonocoxite, with several short setae and 1 long seta. Valvifers expanded posteriorly. Spermatheca elongate, C-shaped.

Variation. In some individuals the dark elytral mark is slightly larger or smaller, and varies from a lighter to darker brown. In some this mark is pale enough to be indistinct. Variation in pro- and mesotibial dilation appears to be sexually dimorphic. Males usually have these tibia more strongly dilated. However, there is enough variation that distinguishing weakly developed males from strongly developed females can be problematic. Weakly developed females have the mesotibia almost parallel-sided to the apex. Strongly developed males have the outer margin of the mesotibia slightly swollen to a widened apex.

Larval description. Mature individuals 6.5 mm; body elongate, slightly curved ventrally, in dorsal view more or less parallel sided and narrowing slightly anteriorly and posteriorly, cylindrical, lightly pigmented except for head, legs and sections of tergum ( Figs. 4 A–E).

Head sclerotized, light brown with faint pattern of longitudinally elongate reticulation, smooth without ornamentation, protracted, prognathous and slightly flattened; epicranial stem absent, frontal arms lyriform and contiguous basally; median epicranial suture distinct and dark, extending nearly the length of frontal arms; 5 stemmata on each side; antenna length just less than half of dorsal length of head at midline, 3-segmented, antennomere 1 slightly shorter than wide, 2 almost twice as long as 1, 3 slightly shorter than 1, sensorium located on ventral apex of antennomere 2, conical, with convex sides, length about 1/2 length of antennomere 3, width slightly more than 1/2 width of antennomere 3; frontoclypeal suture absent; labrum free. Mandibles symmetrical, incisor cleft with dorsal and ventral prongs of nearly equal length, dorsal prong serrate and ventral prong smooth; mola well-developed, asperate with asperites forming transverse rows; accessory ventral process present; prostheca hyaline, with two edges, dorsal edge broadly rounded, ventral edge broad basally and obtusely angulate ( Fig. 4 F). Ventral mouthparts retracted, with well-developed maxillary articulating area; maxilla with transverse cardo, elongate stipes, 3-segmented palp, terminal palpomere 2 times 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 1.5 times width of basal palpomere ( Fig. 4 G), apical palpomere length 1.5 times width. Hypostomal rods diverging; ventral epicranial ridges weakly developed.

Thorax and abdomen with central ½ of T1, anterior ½ of T2–3 and A1–A7, anterior ¾ of A8, and all of A9 pigmented light brown dorsally, sclerotized; sclerotized regions of T1–3 bisected by narrow light-colored midsagittal line; brown areas of all thoracic and abdominal segments, except for their margins, more or less randomly covered with granules; T2–3, A1–8 with straight row of 3 or more pairs of setiferous tubercules along posterior edge of granule field; A9 tergum with pair of urogomphi; base of urogomphi covered with granules, dorsal and lateral margins 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. 4 C–D) with hook at apex, bases of this pair angled in antero-dorsal direction, apical hook shaped like a bird head and neck with bill pointing posteriad ( Figs. 4 C–D), top of “bird head” with rounded prominence and single seta, setal length slightly less than length of tubercle; “bird beak” length about 1 times its vertical width, without sharply curved tip; urogomphi length from basal tubercle t3 to apex <1 times length of remainder of segment; proximal half with about 4 setiferous tubercles, apical half smooth without tubercles. Legs 5-segmented; coxae moderately widely separated, procoxae separated by> 1 times coxal width; meso- and metacoxae separated by> 2 times coxal width ( Fig. 4 E). Spiracles raised, annular-biforous.

Type locality. China, Guangxi Province, Debao County, Fuping village, N23°29.624', E106°12.980'.

Range. Known from Debao and Napo Counties of Guangxi province, China. The range of the host, C. debaoensis , extends to Banshui, Baise City, Guangxi province and Funing County, Yunnan Province with 16 known natural populations ( Xie et al. 2005; Fang 2009).

Material examined. Holotype (by designation) male with the following labels: 1) [rectangular; white; printed in black ink] CHINA, Guangxi, [Debao,] Fuping, ex ♂ cone Cycas debaoensis , N23°29.624', E106°12.980', 21-V- 2004, W. Tang, #331; 2) [rectangular; red; printed in black ink] HOLOTYPE ♂ Cycadophila debaonica G. Xu, W. Tang & P. Skelley 2015 . Deposited in the FSCA. Allotype ( FSCA) and 1683 adult + 329 larval paratypes: CHINA: Guangxi: [Debao Co.]: Fuping, ex ♂ cone Cycas debaoensis , N23°29’50” E106°12’87”, V-2001, W. Lu (241); N23°29.643', E106°12.915', 21-V-2004, W. Tang, #1 (146); N23°29.663', E106°12.903', 21-V-2004, W. Tang, #7 (92); N23°29.655', E106°12.867', 21-V-2004, W. Tang, #31 (97 larvae); N23°29.595', E106°12.944', 21- V-2004, W. Tang, #210 (31 larvae); N23°29.624', E106°12.980', 21-V-2004, W. Tang, #331 (holotype & allotype, FSCA, 535); N23°29.643', E106°12.914', 26-V-2006, W. Tang, #1 (571); N23°29.601', E106°12.862', 26-V-2006, W. Tang, #2 (50+ 85 larvae); N23°29.669', E106°12.909', 26-V-2006, W. Tang, #4 (1+ 8 larvae); 24-V-2008, W. Tang (2+ 108 larvae); [Napo Co.]: Dingye, N23°24’26” E106°01’27”, 22-V-2004, W. Tang, #1 (5); #2 (38). Paratypes deposited at ANIC, BMNH, FSCA, IZCAS, MNHN, NZAC, USNM.

Etymology. Named for the county of collection.

Remarks. The only known host of this beetle is Cycas debaoensis . This cycad occurs in small, relict populations (Tang et al. 2004; Xie et al. 2005) and this beetle species has only been collected from the male cones of this host at two localities. Determination and description of larvae were based on large numbers found associated with adults in C. debaoensis male cones and partial 16S rRNA gene sequences which were identical to the adults. Field observations of the larvae indicate they feed and develop on the male cones of this species in large numbers, feeding on sporophyll tissue. The adults remain on the male cones by the hundreds and dissection of adults confirm cycad pollen in their guts. They typically account for the highest percentage of adult Cycadophila beetles on male cones sampled in the early stage of cone elongation and pollen shed (range 57.6–89.3%, mean = 79.8%, n = 5 cones), but their abundance drops in cones that have nearly completed pollen shedding (range 0–55.6%, mean = 13.6%, n = 7 cones). Adults of other species of Cycadophila of the “XB” type ( Tang et al. 1999) and identified as C. nigra and C. yunnanensis (see below) occur sympatrically within the same cones of C. debaoensis , these being more abundant on male cones that have nearly completed pollen shedding (range = 41.1–100%, mean = 80.7%, n = 7 cones). Larvae of the XB type have not been detected in these cones.

Figures

FIGURE 2. Photographs of Cycadophila debaonica adult male: A – C) Dorsal, ventral and lateral habitus; D) Head to base of elytra, dorsal view; E) Male genitalia.

FIGURE 3. SEMs of Cycadophila debaonica (A, C female; B, D, E male): A) Head, pronotum and elytral base, dorsal view; B) Thorax, ventral view; C) Head and antenna, dorsal view; D) Head, ventral view; E) Protibia and tarsus, ventral view.

FIGURE 4. Photographs of Cycadophila debaonica larva: A – B) Lateral and dorsal habitus; C – D) Terminal segments of abdomen, lateral and dorsal views (t 1 – t 3 indicate basal tubercles of urogomphi); E) Head, ventral view; F) Right mandible, dissected, ventral view; G) Maxillary palp, mala and labial palps, dissected, ventral view.