Xenomorphon, Ferreira & Barbosa & Bocakova & Solodovnikov, 2023

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, Zoological Journal of the Linnean Society 199 (2), pp. 553-566 : 559-560

publication ID

https://doi.org/ 10.1093/zoolinnean/zlad026

publication LSID

lsid:zoobank.org:pub:5F8CB822-E5A6-4E68-8DB6-A5E07104F898

DOI

https://doi.org/10.5281/zenodo.8432516

persistent identifier

https://treatment.plazi.org/id/0388D85F-FFEF-6424-7460-FC3EFE57FF46

treatment provided by

Plazi

scientific name

Xenomorphon
status

gen. nov.

Genus Xenomorphon gen. nov.

( Figs 2–4 View Figure 2 View Figure 3 View Figure 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 View Figure 2 ). Pronotum subquadrate, with a median longitudinal carina developed, scutellar shield absent ( Fig. 2A, 2D View Figure 2 ). Antennae inserted on gibbous prominence, distinctly serrate from antennomeres III–X, with pedicel ca. 3× longer than antennomere III ( Fig. 2A View Figure 2 , 3C View Figure 3 ). Maxillary, labial palps and mandibles fully developed ( Fig. 2E View Figure 2 ). Legs short and stubby, tibiae tapered basally, gradually expanding towards the apex ( Fig. 2B View Figure 2 ). Male genitalia distinctly trilobate ( Fig. 2G View Figure 2 ).

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 View Figure 2 ). Body moderately setose, with short, decumbent yellow setation throughout ( Fig. 2A, B View Figure 2 ).

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 View Figure 2 ). 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 View Figure 2 ).

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 View Figure 2 ). Scape pyriform, approximated at base by half distance of scape width, subconical ( Fig. 2C View Figure 2 ); pedicel minute, ca. 4× shorter than scape; antennomeres III-IX slightly increasing in length towards apex ( Fig. 2A, B View Figure 2 ); antennomere XI round apically ( Figs 2A View Figure 2 , 3A View Figure 3 ).

Mouthparts: mandibles small, hook-shaped, opposable ( Fig. 2E View Figure 2 ). Maxillary palp four-segmented ( Fig. 3B View Figure 3 ); palpomere II elongate, as long as the sum of I + III + IV ( Fig. 2E View Figure 2 ); terminal palpomeres abruptly acuminate ( Fig. 2E View Figure 2 ). Labial palp threesegmented; terminal palpomere slightly blunt ( Fig. 2E View Figure 2 ).

Thorax, prothorax: pronotum nearly as long as wide, subrectangular ( Fig. 2A, D View Figure 2 ); margins distinct and developed, angles round, bearing a median longitudinal carina developed throughout ( Fig. 2A, D View Figure 2 ). Hypomeron slightly concave. Prosternum Y-shaped, posteriorly bifurcated apically, divergent towards procoxae ( Fig. 2B View Figure 2 ). Protrochantins slender and exposed. Procoxal cavity open.

Thorax, mesothorax: mesonotum plate-like, apically round, with angles slightly narrowed ( Fig. 2A, D View Figure 2 ). Mesoscutum anteriorly divided by a tiny median suture (Supporting Information, Supplementary Material 4, Fig. S1 View Figure 1 ). Elytra absent, with no vestiges of wing-base sclerites. Mesospiracles pill-shaped ( Fig. 2B View Figure 2 ). Mesoventrite subtrapezoidal, with distinct visible suture connecting mesoventrite and mesanepisternum ( Fig. 2B View Figure 2 ). Mesotrochantins slender and exposed.

Thorax, metathorax: metanotum plate-like, having round angles; scutellar shield absent ( Fig. 2A, D View Figure 2 ). Membranous wings absent, with no vestiges of wing-base sclerites ( Fig. 2A, D View Figure 2 ). Metaventrite convex, posterolateral angles acute; metadiscrimen complete ( Fig. 2B View Figure 2 ).

Legs: short and stubby ( Fig. 2A, B View Figure 2 ). Coxae conical, obliquely positioned, inner margin nearly contiguous but not touching ( Fig. 2A, B View Figure 2 ); posterior face of metacoxae shallowly excavated. Trochanters shortened; subrectangular, not tubular ( Fig. 2A, B View Figure 2 ). Femora and tibiae subequal in length ( Fig. 2A, B View Figure 2 ); femora parallel sided; tibiae tapered basally, gradually expanding towards the apex ( Fig. 2A, B View Figure 2 ). Tarsal formula 5-5-5; all tarsomeres narrowed; terminal tarsomere bearing two simple claws at end ( Fig. 2A, B View Figure 2 ).

Abdomen: with eight ventrites (sternites II–IX); ventrite seven medially apically notched; ventrite eight lanceolate, elongate, apically acuminate with apex blunt ( Fig. 2B View Figure 2 ). Male genitalia typical elateriformia: trilobate, symmetrical ( Fig. 2G View Figure 2 ); phallobase posteriorly round, median suture absent ( Fig. 2G View Figure 2 ); parameres approximately half the length of median lobe, apices round ( Fig. 2G View Figure 2 ); median lobe elongate, nearly parallel-sided, apically blunt, exposed portion approximately one-quarter longer the length of parameres + phallobase ( Fig. 2G View Figure 2 ).

Distribution. Mexico, Oaxaca, near the municipality of Valle Nacional (estimated 17°14ʹ48.85″N, 96°18ʹ15.31″W; Fig. 3 View Figure 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.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Lycidae

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