Bulasconotus carinisternus Li, Ślipiński & Cai, 2024

Li, Yan-Da, Jin, Zhen-Yu, Ślipiński, Adam, Huang, Di-Ying & Cai, Chen-Yang, 2024, A new species of the extant genus Bulasconotus from mid-Cretaceous Kachin amber (Coleoptera: Zopheridae: Colydiinae), Papéis Avulsos de Zoologia 64, pp. 1-7 : 2

Bulasconotus carinisternus Li, Ślipiński & Cai sp. nov. ( Figs. 1-3 )

Material: Holotype, NIGP203566 .

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

Diagnosis: Bulasconotus carinisternus sp. nov. could be separated from extant B. solomon Ślipiński & Lawrence and B. scaccarius Bernard & Gillett primarily by its medially carinated prosternal process ( Fig. 3C ). In the latter two the prosternal process is generally flat, without median carina ( Fig. 4B ; Bernard & Gillett: fig. 2B). Bulasconotus carinisternus additionally differs from them in the much more slender body, less produced anterior pronotal angles and shorter antennomere 3 (antennomere 3 longer than antennomere 2 in B. solomon and B. scaccarius ).

Description: Body elongate, parallel-sided, about 2.3 mm long, 0.6 mm wide, covered with distinct setae.

Head prognathous, without distinct neck; temples absent; frontal ridges raised above antennal insertions. Compound eyes lateral, entire; interfacetal setae short, scale-like. Antennal grooves absent. Antennal insertions ventrolaterally located. Antennae 11-segmented, short; antennomeres 3-8 subequal in size, about as long as wide or slight wider than long,each narrower and shorter than antennomere 2; antennomeres 9-11 forming loose club. Maxillary palps 4-segmented; terminal palpomere apically flattened, with oblique apical edge. Labial palps 3-segmented; apical palpomere cylindrical. Mentum transverse, parallel-sided, basally with large subtriangular shallow impression. Gular region with short, widely separated and anteriorly convergent sutures.

Pronotal disc subquadrate; anterior angles weakly produced; posterior angles almost right-angled; surface with two pairs of carinae (admedian and sublateral); admedian carinae complex, forked anteriorly and posteriorly. Hypomera without antennal grooves or impressions. Notosternal sutures complete. Prosternum not produced anteriorly; prosternal process with median carina, apically with median carina extending slightly beyond lateral parts. Procoxal cavities externally open.

Scutellar shield slightly longer than wide; lateral margins slightly converging anteriorly. Elytra elongate, parallel-sided, with puncture rows and longitudinal costae; scutellary striole present. Hind wings well developed. Mesocoxae separated by less than one coxal cavity width. Metaventrite with long discrimen. Metacoxae separated by intercoxal process.

Protibiae apically with two spurs and several smaller spines.Tarsi 4-4-4; tarsomeres 1-3 similar in form, togeth- er shorter than tarsomere 4. Pretarsal claws simple, with basal dilation.

Abdomen with five ventrites; ventrites 1 to 3 more solidly fused together than 4 and 5. Ventrite 1 with long and acute intercoxal process. Ventrite 5 with deep and narrow preapical groove parallel to apex.

Etymology: The specific name refers to the medially carinate prosternal process of the new species.

Remaks: Bulasconotus is known in the Recent fauna as two described species living in the Melanesian islands (Ślipiński & Lawrence, 1997; Bernard & Gillett, 2020). The presence of B. scaccarius in Hawaii was thought to be invasive. Extant Bulasconotus can been found among the galleries of ambrosia beetles, and has been suggested as a potential predator of ambrosia beetles ( Bernard & Gillett, 2020).

Figures

Figure 1. General habitus of Bulasconotus carinisternus Li, Ślipiński & Cai sp. nov., holotype, NIGP203566, under incident light. (A) Dorsal view.(B) Ventral view. Scale bars:500 μm.

Figure 2. General habitus of Bulasconotus carinisternus Li, Ślipiński & Cai sp. nov., holotype, NIGP203566,under confocal microscopy.(A) Dorsal view.(B) Ventral view.Scale bars:500 μm.

Figure 3. Details of Bulasconotus carinisternusLi, Ślipiński & Cai sp.nov., holotype,NIGP203566,under confocal microscopy.(A) Head,ventral view.(B) Prothorax, dorsal view. (C) Prothorax, ventral view, with arrowhead indicating the median carina on the prosternal process. (D) Fore leg. (E) Abdominal base, ventral view. (F) Abdominal apex,ventral view.(G) Elytralbase,dorsal view.(H) Head,dorsal view.Abbreviations:a2-11= antennomeres 2-11; amc = admedian carina;el = elytron;lbp =labial palp;md = mandible;mtc= metacoxa;mtes = metanepisternum;mtv= metaventrite;mxp = maxillarypalp;ps = prosternum;ptb = protibia; pts = protarsus;sc = scutellum;slc = sublateral carina;v1-5 = ventrites1-5. Scale bars:100 μm.

Figure 4. Extant Bulasconotussolomon Ślipiński & Lawrence.(A) NHMUK015543699,holotype,dorsal view.(B)NHMUK015543700,paratype,ventral view.Photography by Keita Matsumoto.© NaturalHistory Museum,London,licensed under CC BY 2.0.