Cretakarenni shaoi Li & Cai, 2022

Li, Yan-Da, Huang, Diying & Cai, Chenyang, 2022, Minute clubbed beetles with cephalic horns in midCretaceous amber from northern Myanmar (Coleoptera: Monotomidae), Zoological Systematics 47 (2), pp. 155-164 : 158-161

publication ID	https://doi.org/ 10.11865/zs.2022206
publication LSID	lsid:zoobank.org:pub:4DB19801-C17B-4C50-821B-3244CBF67E47
DOI	https://doi.org/10.5281/zenodo.7172422
persistent identifier	https://treatment.plazi.org/id/03D6E864-FFF8-8E07-FF68-FE03FC6DFD31
treatment provided by	Felipe
scientific name	Cretakarenni shaoi Li & Cai
status	sp. nov.

Treatment

Cretakarenni shaoi Li & Cai , sp. nov. ( Figs 1–6 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 )

Material examined. Holotype, NIGP177331 View Materials , probably male.

Etymology. The species is named after Mr. Yiwei Shao, who kindly donated many valuable fossils for our research.

Locality and horizon. Amber mine located near Noije Bum Village, Tanai Township, Myitkyina District, Kachin State, Myanmar; unnamed horizon, mid-Cretaceous, probably Lower Cenomanian.

Diagnosis. Paired setose projections on vertex narrowly separated (by less than one fifth of maximum head width including eyes) ( Figs 4G View Figure 4 , 6D View Figure 6 ). Elytral absutural lines absent ( Fig. 4I View Figure 4 ).

Description. Adult male. Body elongate, 1.67mm long, 0.58 mm wide, covered with distinct setae.

Head ( Figs 4G View Figure 4 , 6C–D View Figure 6 ) prognathous, posteriorly constricted to form a neck; vertex with a pair of narrowly separated setose projections. Compound eyes lateral, entire, well-developed with many facets. Frontoclypeal suture absent. Antennae ( Fig. 4B View Figure 4 ) apparently 10-segmented; antennal club distinct, apparently 1-segmented. Antennal cavities (subantennal grooves) present, converging posteriorly ( Fig. 6C View Figure 6 ). Mandibles ( Figs 4A View Figure 4 , 6D View Figure 6 ) short and broad, unidentate apically; incisor edge simple, not dentate. Maxillary palps 4(?)-segmented. Labial palps 3-segmented.

Pronotal disc slightly transverse, widest near middle, without impressions; lateral margins slightly curved, smooth; anterior angles broadly rounded, not projecting. Prosternum in front of coxae broad, transverse ( Fig. 4C View Figure 4 ); prosternal process narrower than procoxal cavity width, with a weak longitudinal ridge medially, expanded apically ( Fig. 4C View Figure 4 ). Procoxal cavities externally closed, distinctly transverse ( Figs 4C View Figure 4 , 6A–B View Figure 6 ). Protrochantins exposed ( Fig. 4C View Figure 4 ).

Scutellum with two pairs of setae ( Fig. 4H View Figure 4 ). Elytra truncate apically, not fully covering abdomen ( Fig. 4I View Figure 4 ); elytral absutural lines absent ( Fig. 4I View Figure 4 ). Mesocoxal cavities ( Fig. 6A View Figure 6 ) open, laterally bordered by mesepimeron; distance between mesocoxal cavities narrower than mesocoxal cavity width. Metaventrite broad. Metanepisternum elongate.

Tibiae with distinct apical spurs. Tarsi 5-5-4 ( Fig. 4E View Figure 4 ); basal three (or two in hind legs) tarsomeres with dense hairs; apical two tarsomeres distinctly thinner than basal ones, subglabrous; apical tarsomeres distinctly longer than preapical ones.

Abdomen with 6 ventrites. Ventrite 1 longest, as long as ventrites 2–4 combined (at middle); intercoxal process of ventrite 1 broadly rounded ( Fig. 4F View Figure 4 ).

Remarks. Sexual dimorphisms have been known in both extant ( Sen Gupta, 1988; Liu et al., 2020) and extinct (Jiang et al., 2019; Liu et al., 2020) monotomid beetles. Generally females have 5-segmented metatarsi and five abdominal ventrites, while males have 4-segmented metatarsi and six abdominal ventrites. In Cretakarenni birmanicus, the head of the male is armed with a pair of setose projections (Jiang et al., 2019), while the female has an unmodified head (Peris & Delclòs, 2015). The new specimen studied here possesses 4-segmented metatarsi, six ventrites, and paired setose projections on head, thus it is of high probability to be a male, even though the genitalia are not exposed.