Xenomorphon Ferreira & Barbosa & Bocakova & Solodovnikov 2023, gen. nov.
Creators: name: Ferreira, Vinicius S.
name: Barbosa, Felipe Francisco
name: Bocakova, Milada
name: Solodovnikov, Alexey
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Lycidae
Xenomorphon

description: Genus Xenomorphon gen. nov.
(Figs 2–4)
Zoobank registration. hưp://zoobank.org/ urn:lsid:zoobank. org:act: D958AFA5-4ABA-4AD4-B3DD-7B40E67BCC35
Differential diagnosis. Body dark brown, compressed, elytra and membranous wings absent (Fig. 2A). Pronotum subquadrate, with a median longitudinal carina developed, scutellar shield absent (Fig. 2A, 2D). Antennae inserted on gibbous prominence, distinctly serrate from antennomeres III–X, with pedicel ca. 3× longer than antennomere III (Fig. 2A, 3C). Maxillary, labial palps and mandibles fully developed (Fig. 2E). Legs short and stubby, tibiae tapered basally, gradually expanding towards the apex (Fig. 2B). Male genitalia distinctly trilobate (Fig. 2G).
Etymology. The name of this genus is an allusion to the unique appearance of the studied specimen, which at first thought was not even considered to be a beetle. Xeno‐, from the Greek, ξένος, meaning strange, alien, exotic or different, and morphon, from the Greek μορφῶν, meaning of shape or form. Gender masculine.
Type species. Xenomorphon baranowskii sp. nov.
Description of adult male. General dorsal coloration dark brown, pedicel slightly lighter, yellowish (Fig. 2A). Body moderately setose, with short, decumbent yellow setation throughout (Fig. 2A, B).
Head: as long as wide, widest at eyes, posteriorly covered, in part, by pronotum, hypognathous, inclined, frons strongly bulgy, bearing pits behind antennal insertion (Fig. 2A–C, E). Posterior margin of epistoma clearly emarginate; labrum distinct from clypeus, transverse and small, apparently moveable and connected to clypeus with membrane. Eyes hemispherical, projecting anterolaterally in dorsal view, coarsely granulate (Fig. 2A–C, E).
Antennae: distinctly serrate from antennomere III–IX, densely setose, dorsoventrally flaưened from III–XI, inserted in gibbous prominence at anterior distal portion of head, 11-segmented; in resting position reaching to basal half of body length (Fig. 2A, C). Scape pyriform, approximated at base by half distance of scape width, subconical (Fig. 2C); pedicel minute, ca. 4× shorter than scape; antennomeres III-IX slightly increasing in length towards apex (Fig. 2A, B); antennomere XI round apically (Figs 2A, 3A).
Mouthparts: mandibles small, hook-shaped, opposable (Fig. 2E). Maxillary palp four-segmented (Fig. 3B); palpomere II elongate, as long as the sum of I + III + IV (Fig. 2E); terminal palpomeres abruptly acuminate (Fig. 2E). Labial palp threesegmented; terminal palpomere slightly blunt (Fig. 2E).
Thorax, prothorax: pronotum nearly as long as wide, subrectangular (Fig. 2A, D); margins distinct and developed, angles round, bearing a median longitudinal carina developed throughout (Fig. 2A, D). Hypomeron slightly concave. Prosternum Y-shaped, posteriorly bifurcated apically, divergent towards procoxae (Fig. 2B). Protrochantins slender and exposed. Procoxal cavity open.
Thorax, mesothorax: mesonotum plate-like, apically round, with angles slightly narrowed (Fig. 2A, D). Mesoscutum anteriorly divided by a tiny median suture (Supporting Information, Supplementary Material 4, Fig. S1). Elytra absent, with no vestiges of wing-base sclerites. Mesospiracles pill-shaped (Fig. 2B). Mesoventrite subtrapezoidal, with distinct visible suture connecting mesoventrite and mesanepisternum (Fig. 2B). Mesotrochantins slender and exposed.
Thorax, metathorax: metanotum plate-like, having round angles; scutellar shield absent (Fig. 2A, D). Membranous wings absent, with no vestiges of wing-base sclerites (Fig. 2A, D). Metaventrite convex, posterolateral angles acute; metadiscrimen complete (Fig. 2B).
Legs: short and stubby (Fig. 2A, B). Coxae conical, obliquely positioned, inner margin nearly contiguous but not touching (Fig. 2A, B); posterior face of metacoxae shallowly excavated. Trochanters shortened; subrectangular, not tubular (Fig. 2A, B). Femora and tibiae subequal in length (Fig. 2A, B); femora parallel sided; tibiae tapered basally, gradually expanding towards the apex (Fig. 2A, B). Tarsal formula 5-5-5; all tarsomeres narrowed; terminal tarsomere bearing two simple claws at end (Fig. 2A, B).
Abdomen: with eight ventrites (sternites II–IX); ventrite seven medially apically notched; ventrite eight lanceolate, elongate, apically acuminate with apex blunt (Fig. 2B). Male genitalia typical elateriformia: trilobate, symmetrical (Fig. 2G); phallobase posteriorly round, median suture absent (Fig. 2G); parameres approximately half the length of median lobe, apices round (Fig. 2G); median lobe elongate, nearly parallel-sided, apically blunt, exposed portion approximately one-quarter longer the length of parameres + phallobase (Fig. 2G).
Distribution. Mexico, Oaxaca, near the municipality of Valle Nacional (estimated 17°14ʹ48.85″N, 96°18ʹ15.31″W; Fig. 3).
Biology, immatures and females. Unknown. The only known specimen was collected in the leaf liưer of a pine–oak forest floor, and the female is presumed to be paedomorphic (see Discussion).
Length (head through tip of abdomen). 2.9 mm.
Width (across humerus). 0.5 mm.
description: Published as part of Ferreira, Vinicius S., Barbosa, Felipe Francisco, Bocakova, Milada & Solodovnikov, Alexey, 2023, An extraordinary case of elytra loss in Coleoptera (Elateroidea: Lycidae): discovery and placement of the first anelytrous adult male beetle, pp. 553-566 in Zoological Journal of the Linnean Society 199 (2) on pages 559-560, DOI: 10.1093/zoolinnean/zlad026, http://zenodo.org/record/8432514