Transrenus, Grzymala & Leschen, 2020

Grzymala, Traci L. & Leschen, Richard A. B., 2020, Sexual Dimorphism of New Zealand Puppet Beetles (Aderidae, Coleoptera, Tenebrionoidea): Systematic Revision, Description of Three New Genera, and Phylogeny for Zenascus, gen. n., Zootaxa 4889 (1), pp. 1-59 : 19-20

Transrenus gen. n.

Type species: Transrenus thulater sp. n., here designated.

Etymology. The name is in reference to two of the diagnostic characteristics of this genus—the transverse pronotum and the reniform eye shape. The name is formed by combining the Latin transversus (crosswise) and the Latin renis (kidney).

Diagnosis. The genus Transrenus is distinguished by the broadly transverse pronotum, the unmodified metafemora of both males and females, the base of antennomere 3 subequal in width to the apex of the antennal pedicel, the reniform or kidney-shaped eye, the pubescence of the upper surfaces with long, thin, decumbent primary setae, with 1–2 long, thin secondary setae between each puncture pair, and the male genitalia with the posteriorly truncate phallobase and the basally fused anterior struts. The only other currently described aderid genera with a transverse pronotum are the New World genera Notoxeuglenes Pic from the West Indies and Cnopus Champion (widespread from North to South America), except the relative size of pedicel and antennomere 3. Transrenus is easily separated from Notoxeuglenes based on the overall dark coloration, the lack of any modification to the integument of setae of the metafemora, and the absence of head modifications of males. Members of the genus Cnopus can be easily separated from Transrenus by their minute overall body size (1.1–1.4mm) and the deeper basal pronotal fovea.

Description. Average size for family, length 1.35–1.43 mm. Body about 2× longer than wide. Head abruptly constricted posteriorly, forming a neck, concealed within pronotum. Eyes reniform, moderately protuberant, coarsely faceted, with slight anterior emargination, with short interfacetal setae. Antennal insertions anterad of eyes and eye emargination. Frontoclypeal suture present. Mandible bidentate. Pronotum ( Fig. 6A ) transverse, width greater than length; pronotal width greater than head width, pronotal width less than elytral width, sides slightly rounded, anterior angles rounded, posterior angles rounded; basal margin subequal to apical margin; with two slightly impressed subbasal fovea medially. Prosternal process short, extremely narrowed posteriorly, apex acute. Mesonotum with deep central anterior notch; suture between mesonotum and scutellar shield distinct, straight; scutellar shield ( Fig. 6C ) subquadrate, length approximately equal to width, posterior margin sinuate, lateral apices broadly rounded. Elytral punctures elliptical; subscutellar depression absent; posterior margin rounded, without protrusions. Mesoventrite without procoxal rests. Mesanepisternum with deep, elongate punctation. Mesepimeron with deep punctation. Mesanepisternal-mesepimeral suture faintly indicated by absence of punctures. Mesoventral process ( Fig. 6G ) broad, about 0.66× width of mesocoxa, posterior margin notched, truncate medially. Metaventrite ( Fig. 6E ) with distinct punctures, approximately evenly spaced across entirety of surface; discrimen indistinct, without invagination. Metanepisternum with deep punctures. Metendosternite with moderately long lateral arms; anterior process absent; laminae absent. Proleg with femur ( Fig. 6D ) simple, width subequal basally, medially, and apically; tibia gradually expanded in width apically, without apical spine. Midleg with coxa ( Fig. 7A ) having deep punctures confined to posterior margin and a suture anterad of punctures; femur ( Fig. 7C, 7D ) simple, without modified setae, excavation, ctenidium, or sclerotized rides on posterio-ventral apices, gradually expanded in width medially, medial width approximately 2× width basally and apically; tibial apex not expanded; tarsomere 1 elongate ( Fig. 7B ), length approximately 9× width; tarsomere 2 length subequal to width, expanded ventrally; tarsomere 3 reduced in both length and width; tarsomere 4 length approximately 3.5× width. Abdominal ventrites 1 and 2 connate ( Fig. 7G ), suture not indicated, without appressed, thick field of pubescence, combined length of 1 st and 2 nd ventrites 3× length of ventrite 3; abdominal process broadly rounded; length of 3 rd and 4 th ventrites subequal; deep punctures, subequally spaced apart from one another on ventrites 1–3, smaller, shallower punctures present on ventrites 3–5; ventrite 4 without an elevated plate; ventrite 5 without medial impression. Phallobase posteriorly truncate; apicale with accessory lobes present, each with four setae, all setae subequal; penis with anterior struts present, fused and expanded basally.

Females. Ventrite 5 without medial setiferous sex patch. Apex of last abdominal ventrite and tergite without serration.

Distribution. New Zealand.

Remarks. The phylogenetic relationship of Transrenus to other aderid genera is currently unknown. The size and shape of the antennomeres, the elongate and connate ventrites 1 and 2, and the metafemora without any integument or setal modification indicate a possible relation to the genus Phytobaenus Sahlberg , widespread throughout Europe and Asia. Though there are numerous morphological differences between these two genera, specifically the reniform eye shape of Transrenus is unique amongst aderid taxa.

Figures

FIGURES 6A–G. Transrenus thulater, gen n. sp. n., scanning electron micrographs. (A) pronotum; (B) antenna; (C) scutellum; (D) proleg; (E) elytral integument close-up; (F) elytron; (G) mesoventral and metaventral processes.

FIGURES 7A–G. Transrenus thulater, gen n. sp. n., scanning electron micrographs. (A) metacoxa; (B) metatarsi; (C) metafemur; (D) close-up of metafemur ventro-posterior margin; (E) metaventrite; (F) tergite VII; (G) abdomen.