Phanoceroides

Čiampor, Fedor, Laššová, Kristína, Maier, Crystal A., Čiamporová-Zaťovičová, Zuzana & Kodada, Ján, 2016, Phanoceroides Hinton, 1939: description of new species, morphology of larvae, and revised taxonomic position of the genus (Coleoptera: Elmidae) based on molecular evidence, Zootaxa 4117 (2), pp. 277-288 : 283-286

Redescription of the larva of Phanoceroides

Material examined. 20 larvae ” Venezuela, Amazonas Province, Puerto Ayacucho env., Caño Coromoto above Tobogan de la Selva camp site , stream ca. 2–3m wide, 154 m a.s.l., 05°23'8.1'' N, 067°36'53.9'' W, 1.12.2011, Čiampor Jr. and Čiamporová-Zaťovičová lgt.”,

Length ca. 2.00 mm, greatest width ca. 0.94 mm. Dorsal side yellowish to light brown, ventral side slightly paler; upper part of a head, mouthparts, antennae, margins of tergites and tarsungulus brown. Body ( Figs. 6 a–b) dorsoventrally flattened, tapering posteriorly, metatergum widest; convex dorsally, slightly concave ventrally, crescent shaped in cross section. Biforous spiracles present laterally on mesotergum and abdominal segments I– VIII. Lateral margins of thoracic and abdominal terga terminated with flat, dentate lobes rimmed by sparse fine setae; posterior margins with dense scales.

Head ( Figs. 6 e–f) widened in posterior portion, prognathous, partially retracted into prothorax. Cuticle partly punctured and microreticulate in P. aquaticus , mostly tuberculate in P. fernandesi . Stemmata feebly developed. Antenna ( Figs. 6 c–d) three-segmented, scapus widest with median seta, short in P. aquaticus ; pedicel elongate, thin, microreticulate, ca. five times as long as scapus in P. fernandesi ; pedicel shorter and wider, glabrous in P. aquaticus ; flagellum slightly longer than scapus with apical sensillum; sensorium as long as flagellum (flagellum and sensorium similar in P. aquaticus based on Hinton 1939, Fig. 77). Epicranial and frontoclypeal sutures hardly visible. Clypeus narrow, labrum broader than long with anterior angles broadly rounded, anterior portion covered with yellowish setae ( Fig. 6 g). Mandible subtriangular ( Fig. 6 i) with three subacute apical teeth; prostheca long, setose, penicillus well developed. Maxilla ( Fig. 6 h) slender; cardo small; stipes elongate, with long anterolateral setal tuft; galea and lacinia of subequal length, short with brush of peg-like setae apically; maxillary palpus foursegmented, shorter than galea. Labium ( Fig. 6 h) about twice as long as wide, slightly widened subapically; ligula short, transverse; labial palpi very short.

Thorax. Protergum widest before base ( Figs. 6 a–b), convex; disc with dense tubercles and punctures ( P. fernandesi ) or punctures ( P. aquaticus ) with simple or bifurcated setae ( Fig. 6 q). Lateral margins arched, posterior margin almost straight, anterior margin strongly excised with scales, anterolateral angles subacute. Mesotergum and metatergum about 5 times as wide as long, surface same as on protergum, lateral margins slightly lobate, with long fine setae. Mesotergum with pair of spiracles. Sclerites of proventrite almost fused ( Fig. 6 j), pleural suture and sutures between epimeron and sternellum reduced but slightly visible, prothoracic terga wide; meso- and metaventrite ( Fig. 6 k) divided to wide basisternum, laterotergites and reduced episternum and epimeron, sternellum not visible. Forelegs shortest; mid and hind legs longer, similar in shape. Coxae long and robust, transverse; trochanter about half as long as coxa, distally acuminate; femur slender with sparse spiky shorter hairs; tibia with sparse longer setae; tarsungulus slender, third as long as tibial lenght, curved and acuminate in distal part.

Abdomen ( Fig. 6 k) with nine segments, tergites with very small granulate tubercles (denser in P. fernandesi ), each tergite with one median large tubercle in P. fernandesi , without tubercle in P. aquaticus , ninth tergite with mesal carina (more prominent in P. fernandesi ), sides of tergites lobate and finely dentate with longer brown hairs, posterior margins with dense scales ( Fig. 6 r); lateral parts bearing biforous spiracles, connective horizontal line between pairs of spiracles dentate. Sternites ( Fig. 6 k) I–VIII glabrous, similar in shape, wide and short, bearing special sensilla ( Figs. 6 n–p) and small hairs. Abdominal segment 9 triangular in P. aquaticus ; slightly convex, straight or slightly constricted in P. fernandesi ; apex feebly emarginate. Ventral operculum ( Figs. 6 l–m) subpentagonal, almost twice as long as wide; opercular claws well developed, long and slender; distal margin densely setose; apex rounded in P. aquaticus , subacuminate in P. fernandesi .

Taxonomic position of Phanoceroides

The aligned cox1 matrix of 31 samples had 816 base pairs without indels. Maximum likelihood analysis produced a well-resolved tree, with all Phanoceroides samples grouped in a highly supported clade ( Fig. 7 ). The genus Hypsilara is suggested as the closest relative to Phanoceroides with high support. Both genera are nested within Larainae , however relationships within subfamily are not well resolved. Mean uncorrected p-distance between Hypsilara and Phanoceroides was 14.8%, between Phanoceroides and Phanocerus 17.8% and between Hypsilara and Phanocerus 17.3%. Both Phanoceroides and Hypsilara are distanced by more than 18% from Elminae samples. Therefore Hypsilara and closest relative Phanoceroides are properly placed in the subfamily Larainae .

Figures

FIGURE 6. SEM photos of larvae of Phanoceroides: a – b) habitus, dorsal view; c – d) antenna; e – f) head and anterior part of prothorax; g) labrum; h) maxillae and labium; i) mandible; j) prothorax, ventral view; k) meso-, metathorax and abdomen, ventral view; l – m) ventral operculum; n – p) sensilla of ventral side; q) bifurcated sensilla of dorsal side; r) scales between sclerites, dorsal side. (P. aquaticus: a, c, e, g, h, i, l, q, n, p; P. fernandesi sp. n.: b, d, f, j, k, m, o, r).

FIGURE 7. Maximum likelihood tree. Blue lineage— Hypsilara, green lineage— Phanoceroides. Disersus, Pseudodisersus, Hexanchorus, Phanocerus — Larainae genera. Stegoelmis, Hexacylloepus, Microcylloepus, Gyrelmis, Austrelmis, Heterelmis — Elminae genera. Numbers above branches represent bootstrap support.