Litophallus Bahder & Bartlett, 2025

Bahder, Brian W., Myrie, Wayne, Helmick, Ericka E. & Bartlett, Charles R., 2025, A new genus and species of otiocerine planthopper (Hemiptera: Auchenorrhyncha: Derbidae) from coconut palms (Cocos nucifera) in Jamaica, revised status of Shellenius schellenbergii and an updated molecular phylogeny of New World Otiocerinae, Zootaxa 5723 (2), pp. 209-226 : 217

Litophallus Bahder & Bartlett gen. n.

Type species: Litophallus inornatus Bahder & Bartlett gen. et sp. n.

Diagnosis. Medium-sized. Head in lateral view broad, lachrymiform or broadly rounded and projected for distance greater than maximum width of eye; head broader than long (length 0.5–0.8x greatest width); vertex convex, apex rounded. Vertex narrowly triangular, lateral margins in contact at head apex, disc deeply concave (median carina obsolete). Frons strongly narrowed with lateral margins in close contact for entire length. Pits on lateral margins of vertex and frons. Lateral ocelli obscure or absent. Antennae with scape bearing elongated curved projection (projection shorter than antennal length), pedicel elongated and curved, about 3x longer than scape. Apex of rostrum reaching hind coxae, apical segment short (about as wide as long). Composite vein reaching CuP before wing margin (i.e., clavus open), C5 cell (i.e., procubital cell) closed. Stridulatory plate on trailing margin of hindwing small, with concave external margin. Hind tibia lacking lateral spines, second tarsal segment bearing two apical spines. Hind tibial spinulation 4–(4–5)–2. Aedeagal shaft straight, lacking processes, endosoma simple (lacking processes in type species).

Etymology. The genus name is derived from the Greek word ‘ litos ’ (plain, simple), combined with phallus (with the terminal s in litos dropped for euphony), a reference to the simple aedeagus in the type species. The name is intended as masculine.

Remarks. The new species forms a monophyletic group with S. schellenbergii in all analyses, with 100% support in the combined analysis. Litophallus gen. n. is similar to Shellenius in general habitus and the rounded apex of the head. Litophallus gen. n. differs in that the head is shorter than the greatest width.

The terminalia of the new species differ from Shellenius balli in having a much smaller medioventral process of the pygofer, the gonostyli (ventral view) bear a strong, sclerotized, median hook in S. balli (as opposed to a rounded lobe, Bahder et al. 2023d, fig. 8E), and the aedeagus of S. balli has endosomal processes (none in the new species). Collectively, we believe these support a new genus for the new species and S. schellenbergii . Unfortunately, the male terminalia of S. schellenbergii have not been described and are not available to examine for this species.

Two factors make us cautious about defining a new genus composed of these two species. First, the distribution of S. schellenbergii ( United States) and that of the new species ( Jamaica) is not an expected biogeographic pattern (although we note similar appearing species on iNaturalist in Central, e.g., observation 177454242 from El Salvador, and northern South America, e.g., observation 204624316 from Colombia). Second, the high level of genetic variance between the two may indicate that both taxa represent distinct genera. They are 1.7% and 10.7% different for 18S and the D9–D10 expansion region of 28S, respectively, levels which appear to be genus level differences, albeit for closely related taxa (see Otiocerus and Apache , Figs. 7 & 8 and Tables 3 & 4). Furthermore, the novel taxon differs from S. shellenbergii by a level similar to that which it differs to S. ballii and S. serratus , whereas the two Shellenius species ( S. ballii and S. serratus ) differ from each other by 0.6% percent (for 18S). So while morphological, biogeographical and genetic patterns may suggest that the novel taxon and S. shellenbergii merit distinct genera, it is evident that S. shellenbergii is closer to the novel taxon than Shellenius s.s. and without additional taxa to analyze, elect to transfer S. shellenbergii to Litophallus gen. n. until additional taxon sampling is available.

Figures

FIGURE 7. Adult male Litophallus inornatus gen. et sp. n. forewing venation.

FIGURE 8. Adult male Litophallus inornatus gen. et sp. n. terminalia; (A) lateral view, (B) ventral view and (C) dorsal view.