Anakitium storozhenkoi Arakelyan & Yan, 2025

Arakelyan, Stepan A., Strelnikova, Olesya D., Felker, Anastasia S. & Yan, Evgeny V., 2025, Rare full-body imprint of the giant Asiocoleidae (Coleoptera: Archostemata) from the Lower Triassic sheds light on the morphology of the family, Zootaxa 5715 (1), pp. 41-52 : 42-46

publication ID

https://doi.org/10.11646/zootaxa.5715.1.6

publication LSID

lsid:zoobank.org:pub:9CE17DCD-A1F9-4D4F-924E-4D595C5AB3B3

DOI

https://doi.org/10.5281/zenodo.17888939

persistent identifier

https://treatment.plazi.org/id/1F1B8784-F716-FFFD-FF73-F8BBFBA9434C

treatment provided by

Plazi

scientific name

Anakitium storozhenkoi Arakelyan & Yan
status

sp. nov.

Anakitium storozhenkoi Arakelyan & Yan , sp. nov.

( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Material. Holotype No. 5381/478, A well-preserved almost complete counterpart and the upper half of the part. Deposited in the A.A. Borissiak Paleontological Institute of the Russian Academy of Sciences ( PIN RAS), Moscow, Russia.

Diagnosis. As for the genus (vide supra).

Locality and horizon. Anakit-3 (Bugarikhta Formation, Dvurogian Horizon).

Description. Head. ( Fig. 2A, B View FIGURE 2 ) weakly transverse (L/W = 1.25). Narrowed neck region absent. Vertexal region with three adjacent protuberances ( Fig. 2C View FIGURE 2 ). Antennal sockets covered by P1, which has the same size as P2. Eyes large ( 1.2 mm long), not protruding beyond outline of head, with partially carinated inner margins. Mandibles bidentate, curved; best-preserved right mandible (base to outer tooth) = 1.4 mm, not protruding forward. Penultimate and apical maxillary palpomere ratio 5:3. Antennomeres 1–9 = 4.7 mm ( Fig. 2D View FIGURE 2 ); estimated full length about 6 mm. Scape rounded, 1.4x wider than pedicel; scape, pedicel, and first flagellomere ratio 2:1:2. Second and following flagellomeres moniliform, subequal.

Thorax. Pronotum subrectangular, transverse (W/L = 1.6); sides broadly angulate; posterior margin shallowly emarginate in front of scutellum. Dorsal side with faint longitudinal depression. Propleuron acutely triangular ( Fig. 2E View FIGURE 2 ). Scutellum oval (L/W = 1.4). Middle coxae transverse, completely separated by spear-shaped anteromedian process of metaventrite. Metaventrite max width about 5.3 mm; Metatrochantin exposed, narrow, blade-like, length about 0.9 mm.

Legs. Forelegs: femora about 2.6 mm long; tibiae about 2.85 mm long; tarsomeres 1–5 ratio 0.4: 0.35: 0.4: 0.35: 1; last segment narrowest. Midlegs: left femur = 3.0 mm; left tibiae = 3.25; right metatarsomeres ( Fig. 2F View FIGURE 2 ) 1–5 ratio 0.8: 0.6: 0.4: 0.5: 0.9; first two segments widened anteriorly. Claws = 0.6 mm. Hindlegs: metacoxae lenght = 3.3; metatrochanter = 1.35 mm, tapered basally. Both femora incomplete; estimated length about 3.3–3.7mm. First metatarsomere elongate, = 1.65 mm, second = 0.65 mm

Elytra. ( Fig. 3A, B View FIGURE 3 ). Total length = 19.40 mm, maximum width at midlength = 5.25 mm. Extends 2.0 mm beyond abdominal apex. Base narrower than the remaining part; epipleuron widened proximally near humerus, elsewhere approximately 0.4 mm wide with traces of small tubercles. Apex rounded. Venation weakly visible: 2A curved dorsally; M+Cu and Rs bent toward epipleuron (Rs short). Veins divide elytral surface into four fields ( Fig. 3A View FIGURE 3 ). Field I (between sutural margin and 2A) proximally with six window punctures rows, one terminating abruptly at first quarter of elytral length (hereafter intercalary row Ir), another intercalary row represented by three small punctures. Medially four window punctures rows present in this field, apically only two rows remain. Field II (between 2A and M+Cu) with smoothly curved rows toward humeral margin, two of which terminate abruptly (intercalary rows). Medially field contains four window punctures rows (in transverse section). Field III without intercalary rows, maintaining four rows up to apical part.In distal quarter, window punctures arrangement becomes uniform lacking well-defined rows. Window punctures density 2.5 per mm; longest rows contain approximately 45–50 punctures. Punctures rounded, diameter 0.15–0.20 mm, each with 3–5 maculae ( Fig. 3C View FIGURE 3 ).

Abdomen. ( Fig. 1 View FIGURE 1 ). Cuticle tuberculate. Ventrite I mostly concealed by coxae; Ventrites I–V combined = 9.5 mm. Dimensions I–V (W/median L (mm)): 7.4/1.25; 6.95/2.2; 6.50/1.75; 5.40/1.45; 2.50/2.80. 5 ventrite apex rounded.

Etymology. The new species is named in honor of the entomologist Sergey Y. Storozhenko.

Remarks. Anakitium storozhenkoi sp. nov. is assigned to the family Asiocoleidae based on the elytral structure: the elytra bear rows of punctures not united in pairs; weakly expressed veins on the elytral surface separate rows with similar orientation (fields I–IV); the rows gradually curve towards the humeral bulge; window punctures rows widen toward the elytral base due to the appearance of intercalary ones.

The fossil imprint shows better preservation of the counterimprint. Comparison of symmetrical body parts indicates the beetle underwent significant deformation caused by compression, resulting in multidirectional stretching. For instance, the right mesotibia is 0.4 mm longer than the left one and displays deformation marks. The area between the meso- and prothorax exhibits strong deformation with overlapping ventral and dorsal structures. Some elements likely represent the mesanepisternum and mesoventrite, but poor preservation prevents definitive identification. The middle coxae are poorly discernible but appear weakly transverse. The left metatibia is more completely preserved on direct imprint.The epipleural region of the elytra was likely compressed during fossilization. The short Rs vein probably extended laterally, reaching the basal part of the elytra.

PIN

Paleontological Institute, Russian Academy of Sciences

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Asiocoleidae

Genus

Anakitium

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