Sinomelyris praedecessor, Kolibáč & Huang, 2019

Kolibáč, Jiří & Huang, Diying, 2019, New cleroid beetles from the Middle-Late Jurassic of China, Acta Palaeontologica Polonica 64 (1), pp. 143-155 : 145-148

publication ID	https://doi.org/ 10.4202/app.00550.2018
DOI	https://doi.org/10.5281/zenodo.10987123
persistent identifier	https://treatment.plazi.org/id/2F2187DD-FB3E-FFF2-8A1A-0031FD18FB8D
treatment provided by	Felipe
scientific name	Sinomelyris praedecessor
status	sp. nov.

Treatment

Sinomelyris praedecessor sp. nov.

Figs. 1 View Fig , 2A View Fig , 4A View Fig .

ZooBank LSID: urn:lsid:zoobank.org:act:5A512392-F673-480C-ADBB-52916821AB66

Etymology: From a Latin praedecessor , ancestor.

Type material: Holotype: NIGP168476 View Materials ( Fig. 1B View Fig ); sex unknown, counterpart absent; perfect dorsal side of specimen preserved, elytra open, meso- and metathorax and abdomen visible . Paratypes: NIGP168477 View Materials ( Fig. 1A View Fig ); sex unknown, counterpart absent; perfect dorsal side of specimen preserved, elytra partly open, antennae missing, legs partly visible ; NIGP168478 View Materials ( Fig. 2A View Fig ); 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 View 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 View Materials ); 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 View Fig 1 View Fig , B 2 View Fig ). Pronotum with posterior (basal) margin sinuate at the sides (cf. Figs. 2A 2 View Fig , 3A View Fig );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 View Fig 2 View Fig , B 3, 3B View Fig 1 View Fig ); elytron with sharp, distinct carinae (cf. Figs. 1A View Fig 4 View Fig , B 2 View Fig , 3B View Fig 2 View Fig ); 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 View Fig 2 View Fig ) absent in the fossils as well as in Chalchas Blanchard, 1845 , and other melyrines. Antennomeres from fourth to eighth progressively dilated ( Fig. 2A View Fig 1 View Fig ); in the extant melyrines antenna serrate from fourth antennomere.