Sinomelyris praedecessor Kolibáč & Huang 2019, sp. nov.
Creators: name: Kolibáč, Jiří
name: Huang, Diying
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Melyrides
Sinomelyris
Sinomelyris praedecessor

description: Sinomelyris praedecessor sp. nov.
Figs. 1, 2A, 4A.
ZooBank LSID: urn:lsid:zoobank.org:act: 5A512392-F673-480C-ADBB-52916821AB66
Etymology: From a Latin praedecessor, ancestor.
Type material: Holotype: NIGP168476 (Fig. 1B); sex unknown, counterpart absent; perfect dorsal side of specimen preserved, elytra open, meso- and metathorax and abdomen visible. Paratypes: NIGP168477 (Fig. 1A); sex unknown, counterpart absent; perfect dorsal side of specimen preserved, elytra partly open, antennae missing, legs partly visible; NIGP168478 (Fig. 2A); sex unknown, counterpart absent; perfect dorsal side of specimen preserved incl. fragment of antenna. All from the type locality.
Type locality: Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China.
Type horizon: Haifanggou Formation, Callovian, Middle Jurassic.
Diagnosis.—Relatively small species (body length 6.2– 6.8 mm); body bare; pronotum with single pair of carinae; anterior corners of prothorax obtuse; each elytron with four carinae; tarsomere 1 approximately as long as tarsomere 2 in all pairs of legs; tarsal claw simple.
Description.— Body length (from elytral apex to clypeus): holotype 6.2 mm, paratypes 6.8 and 6.4 mm. For other measurements of visible body parts see Table 2.
Coloration and sculpture: body elongate, rather flat; entire dorsal surface either unicolorous or each elytron with two colour patches, in anterior and posterior thirds. Head coarsely, densely punctate (punctures touch one another; interspaces not larger than half of puncture diameter, mostly reduced to border between neighbouring punctures); pubescence not observed. Pronotum very coarsely and densely punctate (interspaces less than diameter of punctures, most of which touch one another); punctures much larger than those on head, their floors flat, rounded or polygonal in shape; some punctures with short seta growing from the centre. Elytron very coarsely sculptured; punctures large, irregularly shaped, touching one another without distinct interspaces; dorsal surface including humeral margin bare, elytron without pubescence. Ventral surface, antenna and legs without coarse punctation or distinct sculpture and without pubescence.
Head: frons distinctly flat; clypeus distinct, extended anteriorly but frontoclypeal suture absent; antennal socket visible from above; eye relatively large (space between eyes approximately two times as wide as eye diameter), distinctly elevated, not emarginate, elliptic, finely facetted; head distinctly narrowed behind eyes.
Mouthparts: labrum oblong, not emarginate anteriorly; mandible robust, apical tooth acuminate.
Antenna: scape robust, as large as three following antennomeres together; antennomeres progressively dilated from fourth one (only 8 antennomeres recognised in the paratype NIGP168478); whole antenna would be approximately as long as head.
Prothorax: pronotum transverse, approximately 1.4–1.6 times as wide as long; anterior margin straight, not emarginate, anterior corners not projecting, rounded; lateral edge present, evenly rounded; carina along lateral margin of pronotum absent; sides of posterior margin of pronotum sinuate.
Mesothorax: mesonotum transverse; mesocoxal cavities narrowly separated. Each elytron with four distinctly elevated carinae, suture also elevated; interspaces between carinae with two or three rows of punctures.
Metathorax: metaventrite flat and wide, weakly transverse, narrowed towards anterior portion; discriminal line (discrimen) conspicuous along whole length; metacoxal cavities narrowly separated. Membranous wing fully developed.
Legs: mesocoxae oval, metacoxae extended to lateral margin of metathorax; femora weakly clavate; tibiae without row of spines along outer margin, apical spines not observed; tarsomere 1 conspicuous, approximately as long as tarsomere 2; tarsomere 4 approximately as long as 3; tarsomere 5 as long as, or slightly longer than, 1–4 combined; tarsal lobes absent but ventral side of tarsomeres setose; claws large, without denticles; empodium probably small (not observed in well-preserved metatarsus of paratype NIGP 168477); tarsal formula unknown, metatarsi 5-segmented.
Abdomen: five ventrites distinctly visible; pygidium (sex unknown) nearly straight along apical margin.
Remarks.—Habitus as well as body size in the monotypic genus similar to that of extant melyrids of the subfamily Melyrinae (or Melyrini sensu Bouchard et al. 2011), such as, for example, Melyris Fabricius, 1775 or Falsomelyris Pic, 1913 (Fig. 3A 1, B 2). Pronotum with posterior (basal) margin sinuate at the sides (cf. Figs. 2A 2, 3A);punctation of head and pronotum composed of very large punctures with flat floors and a short seta at centre (a pattern denoted as the granular punctation by Kolibáč and Huang [2016]; cf. Figs. 1A 2, B 3, 3B 1); elytron with sharp, distinct carinae (cf. Figs. 1A 4, B 2, 3B 2); elytral sculpture very coarse, irregular, resembling extant members of Melyris; fifth tarsomere as long as tarsomeres 1–4 together; tarsal claw simple, without denticles, as in Melyrodes Gorham, 1882 (Majer 1994a; Constantin 2008). The two carinae running along lateral margins of pronotum in most of the extant species of Melyris (Fig. 3A 2) absent in the fossils as well as in Chalchas Blanchard, 1845, and other melyrines. Antennomeres from fourth to eighth progressively dilated (Fig. 2A 1); in the extant melyrines antenna serrate from fourth antennomere.
Stratigraphic and geographic range.—NE China: Inner Mongolia, Daohugou; Middle Jurassic, Callovian.
description: Published as part of Kolibáč, Jiří & Huang, Diying, 2019, New cleroid beetles from the Middle-Late Jurassic of China, pp. 143-155 in Acta Palaeontologica Polonica 64 (1) on pages 145-148, DOI: 10.4202/app.00550.2018, http://zenodo.org/record/10986992