Neocallotillus Burke

Burke, Alan F. & Zolnerowich, Gregory, 2016, Taxonomic revision of the New World genus Callotillus Wolcott (Cleridae, Tillinae), with the description of the new genus Neocallotillus, and an illustrated key of identification to species, ZooKeys 617, pp. 65-89 : 67-68

Taxon classification Animalia Coleoptera Cleridae

Neocallotillus Burke gen. n.

Type species.

Neocallotillus elegans (Erichson, 1847), here designated.

Differential diagnosis.

Neocallotillus is most closely related to Callotillus . The new genus can be differentiated from Callotillus based on the following combination of characters: in Neocallotillus species the male has antennomeres 1-2 filiform; the third antennomere is moderately serrate; antennomeres 4-9 are strongly pectinate; and the tenth antennomere is ovoid in shape and laterally depressed (Fig. 3 A–C); the length of the tenth antennomere may vary by species. Females have antennomeres 1-3 filiform; the fourth antennomere is moderately serrate; and antennomeres 4-9 are robust, moderately, and gradually increase is size toward the distal end (Fig. 3 D–F); the tenth antennomere of females is similar to that of the males. Males of Callotillus have antennomeres 1-2 filiform; the third antennomere is moderately serrate; antennomeres 4-9 are strongly serrate and approximately equal in length; and the tenth antennomere is broadly ovoid and about the same length as antennomeres 8-9 combined (Fig. 3G, H). The antennal structure of females is similar to that of males, except antennomeres 4-9 are moderately serrate and the tenth antennomere is cylindrical to moderately ovoid (Fig. 3I, J). Additionally, Neocallotillus species are relatively slender and elongate (Figs 1 A–E, 4A), while Callotillus species are conspicuously more robust (Figs 1 F–G, 4B). Neocallotillus species lack an elytral swelling present on the anterior third of the elytral disc of Callotillus (Fig. 4 A–B). Neocallotillus also resembles Barrotillus Rifkind (Fig. 1I), however, the antenna of Neocallotillus is composed of 10 antennomeres (Fig. 3 A–F), while the antenna of Barrotillus has 11 antennomeres (Fig. 3K). The restricted distribution of Barrotillus , recorded only from a confined locality in Honduras, will also serve to separate it from the widely distributed Neocallotillus .

Description.

Size: 3-7 mm. Color: Light testaceous to dark brown (Fig. 1 A–F); costae on elytral disc variously adorned, ranging from light testaceous to brown. Form: small to medium sized individuals; body elongate; elytra subparallel to moderately expanded posteriorly.

Head: Eyes medium sized, moderately taller than wide, conspicuously bulging laterally, strongly emarginate at antennal insertion; diameter of ommatidia small (Fig. 4A); clypeus approximately 3 × the width of eye emargination and moderately emarginate medially. Antennae composed of 10 antennomeres; sexual dimorphism observable in antennal shape, where the antennae are moderately pectinate and strongly depressed dorsoventrally in males (Fig. 3 A–C), but serrate and somewhat depressed dorsoventrally in females (Fig. 3 D–F); tenth antennomere ovoid in both sexes. Labrum elongate, subquadrate; terminal maxillary palp conical, acuminate posteriorly; terminal labial palp securiform.

Thorax: Shape of pronotum scutiform, rounded laterally, narrower than anterior margin of elytra; disc feebly to moderately convex; inconspicuously broader at middle, feebly sinuate, conspicuously constricted on last fourth; anterior depression and antescutellar impression absent. Tibial spur formula 2-2-2, pulvillar formula 4-4-4. Prosternum: Smooth to feebly puncticulate; conspicuously wider than long. Mesoventrite: smooth, puncticulate. Metepisternum visible throughout its length in lateral view, not concealed by elytron. Metaventrite: moderately to strongly convex; variously punctate.

Elytra: Slender to feebly expanded posteriorly, elongate; median region of elytral disc feebly depressed in lateral view; sides subparallel to moderately expanded posteriorly in dorsal view; elytral declivity feebly to moderately gradual; elytral markings always present in various shapes, may be protruding or not.

Legs: Femora smooth, variably vested. Tibiae feebly to moderately rugulose, weakly expanded posteriorly, variously vested. Two tarsal denticles conspicuously separated from each other, inner tarsal denticles trigonal, outer tarsal denticles digitiform.

Abdomen: Smooth to glossy, moderately vested, feebly to moderately convex, with six visible ventrites; lateral margins of ventrites 1-5 parallel, posterior margins truncate; sixth ventrite triangular to subquadrate in shape; male pygidia moderately differentiated from female pygidia (Fig. 5 A–F).

Aedeagus: Moderately robust; phallobasic apodeme short, slender distally; endophallic struts elongate, slender throughout their length.

Etymology: This generic name, which is preceded by the Latin prefix neo (new), refers to the superficial similarity to the genus Callotillus .

Remarks.

Expressing tentative assignment of some of his species to Callotillus , Wolcott (1923) wrote: " Callotillus crusoe , as well as Callotillus elegans and Callotillus vafer , are placed in Callotillus provisionally only, as it differs from the other members of the genus in several important characters. No doubt, eventually, the creation of a new genus will be necessary for the reception of this new species and Callotillus elegans and Callotillus vafer . In Callotillus eburneocinctus , the terminal segment of the maxillary palps is sub-cylindrical, the eyes are emarginate internally and the abdomen has but five segments. In Callotillus elegans , Callotillus vafer , and Callotillus crusoe the maxillary palpi have the terminal segment conical, the eyes are deeply emarginate anteriorly, and the abdomen has six distinct well developed segments". The morphological differences listed by Wolcott, together with the presence of pectinate antennae on males of Neocallotillus versus serrate antennae on males of Callotillus (Fig. 3 A–C, G–H), and an elytral swelling present in Callotillus but absent in Neocallotillus (Fig. 4 A–B), sup port the recognition of two genera within the group. The monotypic Barrotillus was also examined in this study in order to assess possible congenericity with Neocallotillus . The structure of the antennae and number of antennomeres serve as evidence to conclude that these closely related genera should be considered as separate taxa (Fig. 3 A–K).