Nesioeme Niisato, Vives & Heffern, 2020

Niisato, Tatsuya, Vives, Eduard & Heffern, Daniel, 2020, A new genus and species of the tribe Oemini (Coleoptera, Cerambycidae, Cerambycinae) from the Sundaic region, Southeastern Asia, Zootaxa 4755 (3), pp. 553-560 : 554-555

Nesioeme Niisato, Vives & Heffern , new genus

Type species: Nesioeme apicalis Niisato, Vives & Heffern , new species

Description. Body medium in size, short, broad and moderately convex, with short thick legs and antennae; densely pubescent throughout, including legs and antennae.

Head long, quadrate in both dorsal and ventral views, strongly declivous in front; frons strongly transverse, not bordered on sides; intervening area between frons and clypeus forming large transverse concavity, declivous towards clypeus on apical margin; clypeus transversely trapezoidal; genae short, about half width of lower eye lobe in lateral view; antennal tubercles bluntly spinose; tempora almost parallel-sided, slightly narrowed just behind eyes; eyes very widely separated from each other dorsally, deeply emarginate; gula about 2/3 length of basal width of occiput, furrowed and punctured near apical margin; mandibles ( Figs. 6–7 ) short, thick, symmetrical, moderately arcuate on external margins, without any dent on inner margins; maxillae ( Fig. 8 ) each with galea and lacinia weakly developed, palpi shortened in length particularly in basal three palpomeres, terminal palpomere elongate barrelshape; labrum ( Fig. 9 ) semicircular, provided with a tuft of short setae at middle on apical margin; labium with palpi shortened as in maxillae. Antennae short and thick, reaching near middle of elytra even in male, gradually widened to apex in antennomeres III–VII, slightly flattened in VIII‒XI, weakly serrate apico-externally in VI‒X.

Pronotum hexagonal, triangularly produced near middle of sides, distinctly constricted near apex and base, not bordered along apical margin; disc moderately uneven in male, without visible swellings in female, distinctly depressed along basal margin.

Elytra broad and relatively short, slightly ample posteriad, apices together rounded; disc weakly convex, with two longitudinal weak, arcuate costae on each elytron. Hind wings ( Fig. 5 ) almost identical with those of Prosopoeme , but base of MP 3+4 obliquely vent toward MP 1+2.

Prosternum strongly convex except for apical margin; intercoxal process narrow, almost attaining level of hind margins of coxae, distinctly bordered laterally; coxal cavities strongly angulated externally, widely opened behind; internal extensions of propleura not reaching external half of coxae. Mesoventrite with intercoxal process wide, emarginate on apical margin in V-shaped; mesocoxal cavities widely opened to mesepimeron.Abdomen broad, with anal ventrite transversely semicircular in male, transversely trapezoidal in female.

Legs short and stout; femora subfusiform, slightly compressed; tibiae as long as or slightly shorter than femora, almost straight, with a pair of very short terminal spurs; apical parts of tibiae ( Figs. 25–26 ) slightly dilated and faintly produced dorso-forwardly, particularly in male foretibiae; tarsi strongly shortened, with tarsomere I slightly longer than II; hind claws in female ( Fig. 27 ) provided with weak swelling at base on each underside.

Genitalia in both sexes are referred to the description of type species.

Diagnosis. This new genus is distinguished from Prosopoeme and Pacholatkoa by the setose body, the thick and short antennae, and hexagonal pronotum. In the latter two genera, the body is not so setose, only clothed with fine and short pubescence, the antennae are moderately long and surpassing the middle of elytra even in the female, and the pronotum is formed as an elongated trapezium. The hexagonal pronotum in Nesioeme n. gen. resembles that of Noserius Pascoe, 1857 , but is easily differentiated from it by the short, thick setose body and the long head. It also may be similar to the African genera Paroeme Lepesme & Breuning, 1955 , but is distinguished from it by its long head.

Etymology. The genus name Nesioeme is a combination of “ Nesos ” and “ Oeme ” in Greek. “Nesos” means “islands” in Greek and also a second half of the country name of Indonesia which locates the type locality of the new beetle. The gender is feminine.

Range. Sumatra, Borneo and Malay Peninsula. The new genus shows a disjunctive distribution, occurring in the Malay Peninsula, Sumatra and Borneo. These areas are near to the southern periphery of the Sundaic region (Sundaland), which is a biogeographical region of Southeastern Asia corresponding to a large landmass occurring throughout the last 2.6 million years during a period when sea levels were lower.

Notes. This new genus could be related to genera Prosopoeme Aurivillius, 1927 and Pacholatkoa Holzschuh, 1993 . The long head, in particular the elongated occiput, the transverse frons, and the small and widely separated eyes seem to be unique characteristics shared by them among the genera of the subtribe. In fact, Prosopoeme and Pacholatkoa are distinctive genera among Oemina genera. Prosopoeme was originally placed in Oemini ( Aurivillius 1927) , but the tribal placement of Pacholatkoa in the subfamily Cerambycinae is not clear yet (Holszschuh 1993).

Figures

FIGURES 5–9. Hind wing and mouth parts of Nesioeme apicalis Niisato, Vives & Heffern, new genus and new species, holotype female from Sumatra: 5, hind wing; 6, left mandible, dorsal view; 7, right mandible, dorsal view; 8, maxilla, ventral view; 9, labium, ventral view. Scales: 2.50 mm for fig. 5; 0.50 mm for figs. 6‒9.

FIGURES 25–27. Tibia and claw of Nesioeme apicalis Niisato, Vives & Heffern, new genus and new species (SEM images): 25, paratype male from Malay Peninsula; 26, 27, holotype female from Sumatra. 25, 26, apical part of fore tibia; 27, hind claw. Scale: 500 μm for figs. 25, 26; 300 μm for fig. 27.