Seminis Darby, 2016, gen. n.
Creators: name: Darby, Michael
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Ptiliidae
Seminis

description: Seminis gen. n.
(Figs. 7 A–K)
From the Latin noun semen meaning a plant seed, gender neuter. Type species Seminis factiosum sp. n.
Description. Small, rounded, pubescent species easily mistaken for a plant seed. Colour dark brown. Antennomeres 11 segmented, antennomeres 1 and 2 larger than 3–8; 4–8 elongate (5 & 7 longer than remainder), 9–11 forming a loosely jointed club, Fig. 7B. Eyes present. Mentum +/– square. Pronotum without obvious reticulation, slightly wider than elytra, hind angles smoothly rounded in lateral view. Scutellum triangular without any distinctive features. Elytra widest at apex of scutellum, with a short narrow epimeron at the humerus, Fig. 7I. Proventrum narrow, coxae almost contiguous and almost reaching anterior margin, coxal cavities open behind. Mesoventrum, clearly reticulate, collar strongly curved posteriorly at humeri, lateral margins very narrow, hind margins directed anteriorly from procoxal margin, keel reaching beneath mesocoxae in life, ventral surface narrowly eliptical, pubescent, flattened, Figs.7E, F. Metascutellum with two marginal spines Fig. 7K. Metaventrum clearly reticulate, posterior with two sharp points at corners, Fig. 7F. Abdomen: reticulation of ventrites distinct, cells bearing a single posteriorly directed seta alternating with others fringed with microtrichiae, Fig. 7H; tergites II–V with wing folding spicule patches, palisade fringe on tergite VII absent; pygidium composed of tergites IX–X fused, with small apical and two lateral points on posterior margin, anterior margin with row of setae. Fig. 7J; glands as described by Hall (2003) absent. Wings of usual ptiliid type.
Separation from related species. The distinctive spatulate form of the mesoventral keel is similar to that of Nossidium katyae, species of the genus Kuschelidium Johnson and, in a reduced form, to those of Limulopteryx Hall. Of these Seminis is only likely to be confused, if the ventral characters are examined, with Kuschelidium. From that genus it may be separated by the absence of antennal grooves on the proventrum, the shorter elytra, the absence of short carinae running posteriad from the mesocoxal cavities, and the widely separated metacoxae. A similar spatulate mesoventral keel is also present in members of the subfamily Cephaloplectinae but in that case it is a feature of the proventrum and not of the mesoventrum.
Kuschelidium was placed by Johnson in the Ptinellini, and by Sawada and Hirowatari (2002) close to Mikado (in the Nanosellini) although their decision was based on Japanese specimens which differ markedly from K.maori Johnson, the type species of the genus. On ventral characters in particular Seminis looks closest to Acrotrichis and its place in the subfamily Acrotrichinae appears to be confirmed by the presence of the lateral spines on the metascutellum noted by Hall to be absent in all other ptiliid subgroups (Hall 2003, 2005). The symmetrical form of the aedeagus, the incised sternite VI, the form of sternite VII with a short apodeme and the fused tergites IX and X forming the pygidium support that, but it should also be noted that the palisade fringe on tergite VII present in Acrotrichis is absent in Seminis.
Species of Limulopteryx and the Cephaloplectinae are known to be termitophilous, and the possibility exists that species of Seminis (and Nossidium katyae) may also be associated with termites or ants.
description: Published as part of Darby, Michael, 2016, New Species and Records of Costa Rican Featherwing Beetles (Coleoptera: Ptiliidae), pp. 41-51 in Zootaxa 4184 (1) on page 49, DOI: 10.11646/zootaxa.4184.1.2, http://zenodo.org/record/164467