Liacarus (L.) oribatelloides Winkler, 1956

Arabuli, Tea & Gogshelidze, Mariam, 2023, Soil mite (Acari: Oribatida) communities in the limestone quarry of Saskhori (Gerogia), Caucasiana 2, pp. 189-197 : 189

Liacarus (L.) oribatelloides Winkler, 1956

Fig. 4A

Diagnosis.

Large-sized species (1084-1198 × 657-728). Rostrum truncate, with two incisions and small projections laterally, lamellar cusps well developed, distally concaved with strong inner and outer teeth. Translamella with medial tooth; rostral, lamellar and interlamellar setae strong, setiform and slightly barbed. Bothridial setae spindle-form, apex noticeably longer than head, slightly barbed. Notogastral setae are short, thin, and smooth. Epimeral and anogenital setae are setiform and thin. Leg IV trochanters and femora with teeth from the lateral view.

Measurements.

Body length: 1084-1198 (four individuals); body width: 657-728 (four paratypes).

Integument.

Body color brown to dark brown. Notogaster and anogenital surfaces are punctuated with small foveolae. External margin of lamellae, tutoria with striations. Lateral parts of the body granulate with small foveolae.

Prodorsum.

The rostrum is truncate dorso-anteriorly, with two incisions and small lateral teeth. Lamellae longer than half of prodorsum with well-developed translamella and tooth medially. Lamellar cusps are well developed, broad, and extend nearly to the end of the rostrum; the inner cusps are longer (33-36) than the outer ones (15-18). Rostral (68-71), lamellar (94-123), and interlamellar (193-205) setae are setiform and slightly barbed. Sensilli (128-132) spindle-form slightly barbed; the apical part is longer (57-68) than the length of the head (34-41). Notogaster slightly narrows anteriorly and posteriorly, with very small humeral projections. Notogaster with eleven pairs of minutes, glabrous setae (15-18) except seta p1, which is longer (34-38), and easily separated from the other ones. Ventral side. Epimeres I-III well separated with parallel lines, laterally integument granulated; epimeral formula 3:1:3:3. Epimeral setae setiform, slightly barbed, 1a, 2a and 3a short, 1b, and 3b longer than other setae.

Anogenital region.

Six pairs of genitals, one pair of aggenital, two pairs of anal and three pairs of adanal setae setiform. Genital plate wider than long (87-91 and 57-63, respectively). Anal plate nearly as long as wide (132-136 and 119-125, respectively). Length of anal setae 22-27.

Legs. Legs three-clawed. Formulae of leg setation and solenidia: I (1-5-3-4-20) [1-2-2], II (1-4-2-4-16) [1-1-2], III (2-3-1-3-15) [1-1-0], IV (1-2-2-3-12) [0-1-0]; All setae setiform, slightly barbed on the dorsal sides of the legs. Leg IV trochanter and femora have a long, slender appendage from the lateral view.

Differential diagnosis.

According to the morphological diagnostic features of the available specimens of Liacarus oribatelloides collected from the limestone quarry of Saskhori and L. coracinus collected from Machakhela National Park ( Gratiashvili et al. 2022), the various characteristics are different between these closely related species.

Compared to L. coracinus , which has a more oval-shaped body and a yellow-brown color, L. oribatelloides has an elongated body with a dark-brown or black color.

The species is distinguished most readily by the lamellar cuspids. L. oribatelloides has strongly elongated tips of the lamellar cuspids on both the inner and outer sides (Fig. 4A ), whereas L. coracinus has strong inner and indistinct outer teeth of the lamellar cusps. The distance between the outer teeth of the lamellar cusps is also noticeably different between the species; they are wider for L. oribatelloides than for L. coracinus , and represent 36-38 and 25, respectively.

Liacarus oribatelloides and L. coracinus also differ from each other by the length of leg IV, which is 225 and 165, respectively. In addition, the femur of leg IV of L. oribatelloides has clearly distinguishable inner teeth (Fig. 5 ). In having the combination of a shape of lamellae with well-developed lamellar cusps, a shape of sensilli, and the presence of an inner tooth in the femur of leg IV, L. oribatelloides differs from L. coracinus .

Remarks.

The taxonomic status of Liacarus oribatelloides is unclear. Weigmann (2006) registered L. oribatelloides in southern Germany and gave the differential diagnosis with the drawings for L. coracinus and L. oribatelloides .

During a long period of time, Liacarus oribatelloides was registered as a valid species, but in the latest world catalog of oribatid mites ( Subías 2023) and some other publications ( Schatz 2018), the species is synonymized with L. coracinus . According to the literature data, L. oribatelloides is distributed in the Czech Republic, Southern Germany, Austria, Italy, Slovakia, Poland, the Central Alps, and the Tatra Mountains (Fischer & Schatz 2013; Schatz 2016; Miko 2016; Wierzbicka et al. 2020; Miko 2021; Jászayová et al. 2023). Before our finding, the species distribution was known only from Central Europe, and the species had never been found in the Caucasus region.

The taxonomy of Liacarus oribatelloides and similar taxa needs to be studied further. In particular, using the molecular genetic framework is necessary in order to better understand species status and delineate interspecific boundaries.

Figures

Figure 4. A: Lamellae with inner and outer cusps of Liacarus oribatelloides Winkler, 1956; B: Lamellae with inner and outer cusps of Liacarus (L) Liacarus brevilamellatus Mihelcic, 1955.

Figure 5. Liacarus oribatelloides Winkler, 1956. Femur of leg IV with inner tooth