Shellenius serratus Bahder & Bartlett, 2023

Bahder, Brian W., Zumbado Echavarria, Marco A., Barrantes Barrantes, Edwin A., Helmick, Ericka E. & Bartlett, Charles R., 2023, A new species of planthopper in the genus Shellenius (Hemiptera: Fulgoroidea: Derbidae) from palms in Costa Rica, Zootaxa 5306 (5), pp. 571-585 : 575-581

Shellenius serratus Bahder & Bartlett sp. n.

( Figures 2–6 )

Type locality. Costa Rica, Heredia, La Selva Biological Station .

Diagnosis. Body and forewings mainly yellow with red wash on portions of head, red patches near anteriolateral margin of mesonotum, and a diagonal red line (bifurcating at apex) for near entire length of forewing. Head broad (relative to other members of genus) with serrations along dorsal margin and subapical transverse carina resulting in a subapical inflection of the head. Male pygofer with triangular medioapical process (with a thin flange on ental side, giving the process a doubled appearance from lateral view). Aedeagus with diagonal row of 4 large teeth ventrally near apex, plus 2 short and 2 long apical processes; endosoma with large irregular membranous portion with two large processes.

Description. Color. Body yellow with legs more pallid, vertex and dorsal half of frons washed with red, in lateral view red color present in dorsal half of genae with ventral margin of red patch strongly sinuate ( Fig. 2 ); in dorsal view, disc of vertex with blackish patch between eyes. Mesonotum with two red patches near anteriolateral margins. Forewings translucent basally, yellow distally (and along costal margin), with red stripe extending lengthwise from base to forewing apex, bifurcating near distal apex of cell C2 ( Fig. 4 ).

Structure. Body length (including wings) males: 11.1 mm (n = 1) and females: 13.4 mm (n =2) ( Table 3 ). Head. In lateral view ( Fig. 3A ), head broad and strongly projecting anteriorly (about 2.5x width of eye, widest head height about equal to head projection beyond eye); dorsal margin straight (between eye and fastigium) with minute serrulations along length; at apex slightly inflected dorsad with transverse carina, anterior margin rounded, ventral margin weakly convex; lateral portion of head marked with two obscure carina: one extending anteriorly over top of eye, slightly declining then inclining to end in lateral carina of vertex near apex; a second carina from lateral extreme of transverse carina extending posteriorly at weak diagonal, becoming obsolete well before eye. In dorsal view, strongly compressed, vertex widest at base, constricting distally (disc of vertex obsolete near midlength), posterior margin slightly concave, anterior margin linear, frons visible beyond transverse carina from dorsal view ( Fig. 3B ). Eyes large, laterally projecting, in lateral view rounded with large posterior emargination; ocelli apparently absent. Antennae with long sinuate process, nearly as long as antennae.

Thorax. Pronotum in dorsal view very short at midline, anterior margin convex, posterior margin strongly and deeply invaginated making a nearly quadrate concavity ( Fig. 3B ), in lateral view pronotum weakly declining anteriorly, paradiscal region relatively small, cupped, extending to lower level of eye. Mesonotum in dorsal view with single carina at midline, approximately as wide as long, in lateral view, slightly arched (scutellum not clearly separated from scutum; Fig. 3A ). Hind leg lacking lateral spines on tibia; spinulation formula: 5-3-2. Forewing slender very elongate, length males: 7.64 mm; females: 8.01 mm, spatulate, widest subapically, apex irregularly rounded; CuA anastomosing to form closed C5 (procubital) cell; clavus open, composite vein Pcu+A1 joined with CuP and CuA before extending to wing margin; branching pattern RA 2-branched, RP 3-branched, MP 7-branched, CuA 2-branched.

Terminalia. Pygofer in lateral view narrow, irregular in form; widest at ventral margin, narrowest dorsally, irregularly sinuate on anterior and posterior margin, posterior margin forms truncated process with slight invagination just below dorsal margin ( Fig. 5A ); in ventral view, medioventral process present, broadly triangular, base wide, nearly reaching lateral margins, bi-layered with inner process slight larger than external process ( Fig. 5B ). Gonostyli in lateral view elongate, scoop-like, somewhat upcurved, nearly uniform in width across length (slightly constricted at base), dorsal and ventral margins irregularly sinuate, apex rounded, curved dorsad ( Fig. 5A ). In ventral view, gonostyli narrow basally, expanding greatly at midpoint with inner margins forming beak-like processes, curving slightly cephalad, narrowing distally near apex then expanding to rounded apices bearing subapical processes on inner margin, angled cephalad with sclerotized, hooked apices, curving caudad ( Fig. 5B ). Aedeagus cylindrical, distally upcurved, bearing bilaterally asymmetrical processes ( Figs. 6 & 7 ), including a pair of short, robust apical processes ( Fig. 7 , A 1 & A 2 ) curved dorsad; right lateral side with one robust process (A3) angled cephalad, reaching approximately 1/3 point of aedeagus; left lateral side with three robust processes ( Fig. 7B, A 4 , A 5 , and A6) arising subapically, approximately equal in length, dorsal most process (A4), nearly straight, angled slightly dorsad, middle process (A5) with dorsal margin sinuate, curved dorsad, ventral most process (A6) with dorsal and ventral margins sinuate, generally angled cephalad with apex curving dorsad. Four small processes in a row on right ventral margin ( Fig. 7D, A7–A 10 ), basal process (A7) anvil-shaped, next process (A8) curved spine angled caudad, A9 similar to A8, and A10 similar to A8 and A9 but reduced in size. Endosoma complex with two large sclerotized processes, the first ( Fig. 7B, E 1 ) arising on right lateral side, long, nearly reaching base of aedeagal shaft, extending along dorsal margin and second process (E2) arising on left lateral side, similar in shape to E2, slightly shorts, extending along lateral margin. Anal segment elongate (subequal in length to gonostyli), in lateral view weakly expanding distally, irregularly sinuate on dorsal and ventral margins, apex narrowed greatly and curved ventrad ( Fig. 5A ).

Plant associations. Unknown palms ( Arecaceae ).

Distribution. Heredia Province, Costa Rica.

Etymology. The specific name is given in reference to the serrated appearance of the dorsal part of the head in lateral view and ventral margin of the aedeagus. The specific name is derived from the Latin word serratus (toothed like a saw), with the masculine (– us) ending to match the gender of Shellenius .

Material examined. Holotype male, “ Costa Rica, Heredia Pr. / La Selva Biological Station / 12.V.2018, sweeping palms / Coll.: B.W.Bahder // Holotype / Shellenius serratus J /” ( FLREC) ; Paratypes, 2 females, same as holotype ( FLREC) .

Sequence data. For the COI locus, sequences for Shellenius serratus sp. n. (712 bp), S. schellenbergii (684 bp), S. ballii (712 bp), Patara vanduzei (714 bp), and Mula resonans (599 bp) were generated ( Table 2 ). For the 18S locus, sequences for Shellenius serratus sp. n. (1,632 bp), S. schellenbergii (1,626 bp), S. ballii (1,633 bp), Patara vanduzei (1,297 bp), and Mula resonans (1,062 bp) were generated ( Table 2 ). The Maximum Likelihood phylogeny generated for COI demonstrates weak bootstrap support (<50) for all branches in the tree ( Fig. 12 ) whereas most branches in the phylogeny generated based on 18S showed strong bootstrap support (>95) except for the relationship of Shellenius to Patara , which was moderate to weak (61) ( Fig. 12 ). Additionally, Shellenius serratus sp. n. resolved adjacent to S. ballii (the type species of Shellenius ) with strong bootstrap support (95) with the genus also being strongly supported (98) based on 18S for the taxa analyzed ( Fig. 12 ). The consensus tree generated from concatenated COI and 18S sequences data showed strong bootstrap support (98) for Shellenius and moderate bootstrap support (72) for placement of Shellenius serratus sp. n. adjacent to S. ballii ( Fig. 12 ).

Remarks. The novel taxon, while resolving with other species of Shellenius based on available sequence data and displaying morphological similarities to other members of Shellenius , appears unique among congeners. The head characteristics of Shellenius serratus sp. n. seem closest to Shellenius , however, the relatively straight vertex (in lateral view) with the apical inflection is very similar to Otiocerus (from which Shellenius was segregated by Ball 1928). The diagnostic differences among the genera Shellenius , Otiocerus , and Apache have historically relied on the shape of the head (e.g., Bartlett et al. 2011, 2014). The monophyly of the New World genera of Otiocerini has not yet been verified using molecular tools. Also, the male terminalia, the usual source of definitive species diagnostics, has not been described for most species of Otiocerus and Shellenius (the two Apache species were described by Wilkey 1963). However, Hendrix & Bartlett (in press) illustrate the terminalia of three species of Otiocerus . The aedeagus of each of the 3 Otiocerus species illustrated in Hendrix & Bartlett (in press) includes 7 processes (1 elongate process on the shaft, 2 apical processes, and 4 subapical retrorse processes) with carrying details, but no conspicuous membranous endosoma.

At present, male terminalia has not been described for any Shellenius species outside of the new species and S. ballii in this work. Species diagnostics are based mostly on differences in color patterns and the shape of the head. Among species of Shellenius , S. serratus sp. n. is most similar to taxa with a relatively short and broad head (viz. S. schellenbergii [ Fig. 9 ] and S. griseus [ Fig. 13B ]), but among these species S. serratus sp. n. is unique is possessing the apical inflection near the dorsal apex of the head, and appears to be the only species in the genus with red spots on the anterior margin of the mesonotum. Shellenius serratus sp. n. also lacks the longitudinal black marking found on the head of S. griseus , and S. schellenbergii is more extensively washed with red on the head and forewings.

Figures

FIGURE 1. Habitat and locality of Shellenius serratus sp. n.

FIGURE 2. Adult habitus of male Shellenius serratus sp. n.; (A) lateral view and (B) dorsal view.

FIGURE 3. Adult Shellenius serratus sp. n.; (A) head, pronotum, mesonotum lateral view, (B) head, pronotum, and mesonotum dorsal view and (C) head frontal view; scale = 1 mm.

FIGURE 4. Male Shellenius serratus sp. n. forewing venation; black = vein, green = cell, italics = crossvein.

FIGURE 5. Male Shellenius serratus sp. n. terminalia; (A) lateral view, (B) ventral view, and (C) dorsal view.

FIGURE 6. Aedeagus of Shellenius serratus sp. n.; (A) right lateral view, (B) left lateral view, (C) dorsal view, and (D) ventral view.

FIGURE 7. Line art of aedeagus of Shellenius serratus sp. n.; (A) right lateral view, (B) left lateral view, (C) dorsal view, and (D) ventral view.

FIGURE 9. Lateral habitus of an adult female Shellenius schellenbergii; scale = 1 mm.

FIGURE 10. Adult male of Patara vanduzei; (A) habitus lateral view, (B) habitus dorsal view, (C) terminalia lateral view, (D) terminalia ventral view, (E) aedeagus right lateral view, (F) aedeagus left lateral view and (G) aedeagus dorsal view; scale = 1 mm.

FIGURE 12. Maximum Likelihood trees (1,000 replicates) demonstrating the relationship of Shellenius serratus sp. n. relative to other available species of Shellenius; (A) COI, (B)18S and (C) consensus tree based on concatenated COI and 18S sequence data, scale bar = percent nucleotide difference.

FIGURE 13. Lateral views of type material of Fowler Otiocerus species from BMNH now placed in Shellenius; (A) Shellenius montanus, (B) Shellenius griseus, (C) Shellenius gracilior, and (D) Shellenius interruptus, new comb.