Lepidochaetus tirjakovae

Reference

Križanová F. & Vďačný P. (2021) Description of Lepidochaetus tirjakovae sp. nov. (Gastrotricha: Paucitubulatina: Chaetonotidae), using morphology and DNA barcoding. Zoologischer Anzeiger 292: 207‒224. https://doi.org/10.1016/j.jcz.2021.04.003

Lepidochaetus tirjakovae, schematic drawings. (A) Dorsal view. (B) Ventral view. (C) Internal morphology. (D–J, L) Schematic drawings of eight types of scales. (K) Lateral view of an almost rectangular dorsal scale shown in (J). (M) Detail of an elongated rearmost lateral spine showing the denticle (arrowhead). Scale bars: 50 µm (A, B) and 100 µm (C).

Diagnosis

Body stocky and about 180‒232 µm long. Head hammer-shaped, with clearly demarcated cephalion, epipleurae, and hypopleurae. Ocellar granules absent. Mouth ventral, without cuticular tooth. Pharynx wide, with anterior and posterior swellings. Intestine straight, without any anteriorly differentiated section. Scales distributed in 22 columns, 30–32 scales per column. Dorsal surface covered from almost beginning of to mid-portion of epipleurae by small, very broadly obovate scales bearing short spines and from mid-portion of epipleurae to posterior trunk region by more or less rectangular scales with rounded edges and relatively long spines. Terminal dorsal body region covered by (i) one pair of almost circular scales with short curved denticles, (ii) multiple rounded scales with short fine spines, (iii) three pairs of roughly rectangular lateral scales with long spines bearing a lateral denticle, and (iv) one semilunar median scale with a long straight spine. Ventral surface bears two ciliary rows ending before terminal body region. Interciliary field and lateral ventral sides covered by roughly rectangular scales with rounded edges and relatively short spines. Terminal ventral body region covered by (i) one pair of spineless oval scales located anterior to furca branches, (ii) five broadly oblong scales with a conical anterior end and short spines, located posterior to interciliary field, and arranged in two horizontal rows‒two smaller scales in anterior row and three larger scales in posterior row, and (iii) multiple lateral almost rectangular scales with rounded edges and relatively short spines. Antero-lateral edges of scales adhere to each other except for small anteriormost dorsal broadly obovate scales, small terminal dorsal rounded scales, median semilunar scale, and upper-furcal ventral pair of oval scales. Double edge only along anterior side of roughly rectangular scales and anterior half of broadly oblong scales, while around whole perimeter of all other types of scales. Dorsal spines slightly increasing in length from head to posterior trunk region, gradually tapering to become hair-like terminally. Ventral and ventrolateral spines shorter than dorsal ones. Furca base very short, carries well-developed adhesive tubes.

Type material

HOLOTYPE. Adult, CU-FNS-26-9-19/HO.

PARATYPES. Two adults, hologenophores (specimens VR 1 and VR 4), CU-FNS-11-9-19/PA-1 and CU-FNS-13-9-19/PA-2.

Type locality

Vajspeterský rybník fishpond, Rača, Bratislava, Podunajská rovina plain, Slovakia, 48°12′20.8″N, 17°07′42.4″ E.