Cretorhadalus constantini Kolibac & Prokop gen. et, 2023

Kolibac, Jiri, Rosova, Katerina, Prazak, Jan Simon, Hammel, Joerg U. & Prokop, Jakub, 2023, The first larva of the cucujiform superfamily Cleroidea from the Mesozoic and its ecological implications (Coleoptera), Arthropod Systematics & amp; Phylogeny 81, pp. 289-301 : 289

publication ID	https://dx.doi.org/10.3897/asp.81.e98418
publication LSID	lsid:zoobank.org:pub:8EE85535-FA17-418B-B1BA-6929C4EC7F34
persistent identifier	https://treatment.plazi.org/id/1D88FD1F-B283-4738-A7FC-BA95C2ECD61E
taxon LSID	lsid:zoobank.org:act:1D88FD1F-B283-4738-A7FC-BA95C2ECD61E
treatment provided by	Arthropod Systematics & Phylogeny by Pensoft
scientific name	Cretorhadalus constantini Kolibac & Prokop gen. et
status	sp. nov.

Treatment

Cretorhadalus constantini Kolibac & Prokop gen. et sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 5 View Figure 5

Type material.

Holotype PřFUK 20 preserved in a polished, transparent yellow piece of amber (18.1 × 9.9 × 3.6 mm); deposited in the collection of Charles University, Faculty of Science, Department of Zoology, Prague.

Type stratum.

Lowermost Cenomanian (Upper Cretaceous); age based on U-Pb dating of zircon crystals from the volcaniclastic matrix ( Shi et al. 2012).

Type locality.

Hukawng Valley, Kachin State, northern Myanmar.

Description.

Body length from clypeus to the last abdominal segment (excluding urogomphi) 2.41 mm. For other measurements see Table 3 View Table 3 .

Body habitus and pubescence (Fig. 1A, B View Figure 1 ): Body elongate, whitish, sclerotized parts brown. Head capsule, urogomphi and dorsal part of abdominal segment IX heavily sclerotized, dark brown (urogomphi lighter than tergite IX); prosternum, protergum and mesotergum with sclerotized brown plates; metathorax and abdomen up to segment VIII whitish. Cranium with long sparse pubescence dispersed irregularly (c. 50-60 setae on dorsal side and c. 20 setae on ventral side); dorsum of thoracic segments with c. 10-15 long setae; legs with few long setae; abdominal segments I-VIII with dorsally about 2-4 long and laterally about 5 setae; sides of abdominal segments IX-X with dense and long pubescence, urogomphi also with long setae. Ventral sides of thoracic and abdominal segments with shorter and sparser pubescence. - Head: Cranium approximately as wide as long, lateral sides weakly rounded (convex), its anterior margin wider than base (Table 1 View Table 1 ; Figs 1C View Figure 1 , 4C View Figure 4 ); five stemmata occur on each side with the formula 2+3 (two posterior and three anterior) (Fig. 2C View Figure 2 ); frontal arms distinctly Y-shaped, with branches curved at half their length and divergent (Fig. 4C View Figure 4 ); median endocarina absent (Fig. 1C View Figure 1 ); frontoclypeal suture present (Fig. 1A, C View Figure 1 ); gular sutures widely separated, subparallel, virtually extending to anterior part of cranium (Fig. 5 View Figure 5 ); hypostomal rods absent; paragular sclerites absent. Gular region membranous and pale, its middle part nearly reaching midpoint of cranium so that the maxillolabial complex reaches slightly beyond half of cranium; head capsule is ventrally open, without bridge along anterior margin (Figs 1D View Figure 1 , 5 View Figure 5 ). - Antennae (Figs 1D View Figure 1 ; 2B, D View Figure 2 ): 3-segmented, 1st antennomere shorter than 2nd, the latter obliquely truncated and shorter than 3rd; sensory appendix relatively short and stout, triangular, not extending behind one quarter of 3rd antennomere, which is relatively slender and long, with long seta on apex. - Mandible (Figs 1D View Figure 1 , 2A View Figure 2 ): bidentate (Fig. 2A View Figure 2 ), that is with two apical teeth situated side by side; other mandibular structures not visible in fossil. - Maxilla (Figs 2D View Figure 2 , 5 View Figure 5 ): mala small, triangular, with at least 3 thick long setae along outer margin; pedunculate seta not observed; palpi 3-segmented, 1st and 2nd palpomeres equal in length, terminal palpomere coniform and longer than 1 or 2; cardo and stipes distinctly separated; cardo narrow and transverse, much smaller than stipes (Fig. 5 View Figure 5 ). - Labium (Figs 1A View Figure 1 , 2A View Figure 2 , 5 View Figure 5 ): ligula small, pale, membranous, ciliate, rounded; palpi 2-segmented, terminal palpomere cylindrical, about twice as long as basal palpomere; prementum in single part (not divided); border of postmentum not conspicuous. - Labrum (Figs 1C View Figure 1 , 2E View Figure 2 , 5 View Figure 5 ): free; anterior margin wide and convex, with about 6 long setae (Fig. 5 View Figure 5 ); other details not visible. - Thorax (Fig. 1A, B, C View Figure 1 ): protergum heavily sclerotized and pigmented, with single large tergal plate longitudinally divided by medial suture; mesotergum with pair of small but distinctly pigmented and sclerotized tergites; structure of metatergum the same as that of mesotergum, but sclerites slightly smaller (Fig. 1C View Figure 1 ). Ventral part of pro-, meso- and metathorax without distinctly pigmented sclerites. - Legs (Fig. 1B, C View Figure 1 ): Coxae projecting; trochanters rather triangular; femora longer than tibiae; tarsunguli without visible setae. - Abdomen: segments I-VIII membranous, their terga without sclerites (tergites) or pigmented plates (Figs 1A View Figure 1 , 2E View Figure 2 ); segment IX with single tergite (not transversely divided into two parts) bearing a pair of slender hooked urogomphi (Fig. 2E View Figure 2 ); median process or glandular openings on or between urogomphi not visible, but it is possible that a pair of membranous appendages are present approximately at the centre of tergite IX; urogomphi without large tubercles, relatively slender, conspicuously turned upwards, well-developed (Fig. 1E View Figure 1 ; cf. Fig. 3B, D View Figure 3 ).

Etymology.

The specific epithet honours Robert Constantin (Saint Lô, France), the eminent specialist of beetles in the melyrid lineage and leading authority on their larvae.