Kunstidamaeus fraterculus, Miko, L., 2010

Miko, L., 2010, Taxonomy of European Damaeidae (Acari: Oribatida) III. Species of the Kunstidamaeus tenuipes (Michael, 1885) group, with a description of Kunstidamaeus fraterculus n. sp. from East Slovakia, Zootaxa 2327, pp. 51-64 : 60-63

Kunstidamaeus fraterculus n.sp. Fig. 8-10

Diagnosis. Smaller Kunstidamaeus with granulated body surface, densely barbed sensillus, most of the prodorsal and notogastral setae covered by spinuli or fine hairs. Spinae adnatae quite short and straight, not curved. Propodolateral apophysis P developed as a sharp perpendicular tip, parastigmatic apophyses unequal, Sa much longer, with sharp tip, Sp shorter, triangular or pentagonal, with angular tip. Ventral tubercles Va and Vp present, tubercular. Legs comparatively short, only leg IV longer than body.

Material examined. 2 individuals of the species have been collected 30.3.1990 by author on Dreveník hill, East Slovakia (locus typicus), in samples labelled LM-62-90 and LM-65-90b . Holotype was collected in the area of travertine rocks called Skalny raj ("Rocky Paradise") , in rhizosphere of grasses on the rocks (550 m). Paratype was collected in upper soil layer of grassland on Drevenik plateau (600 m) . Holotype is deposited in Acarological Collections of Staatliches Museum für Naturkunde Görlitz (Germany), paratype in the author’s collection. Only holotype was studied in detail in order to keep paratype intact, given the very limited material available. Immatures were not collected.

Description of the adult. Body (Fig. 8A,B) relatively small, body length 562 µm. Prodorsum length ca 175 µm, breadth 215 µm. Notogaster length 402 µm and breadth 356 µm. Surface of the body with distinct granular cerotegument, granules larger on dorsal and finer on ventral side of the body. Except of granulation, body also covered by columnar and filamentous cerotegument (dorsosejugal area, ventral part of prodorsum).

Prodorsum (Fig. 8A) broadly triangular, with distinct granular sculpture and quite thick layer of mostly filamentous cerotegument. Two indistinct longitudinal ridges, slightly converging anteriad, present in interbothridial area, reaching about the level of insertions of interlamellar setae. Propodolateral apophysis P (Fig. 8A, 9A) perpendicular, sharp, tooth-like. Postbothridial area with typical set of two pairs of tubercles (Ba, La), Ba being more distinct in dorsal view. Anterior to bothridiae, in the area of lateral part of prodorsal furrow, prodorsal enantiophysis is slightly indicated, with posterior tubercle or ridge (Ap) more apparent (Fig. 9B). Parastigmatic apophyses differently shaped (Fig. 9A), anterior apophyse (Sa) quite long, protruding, fine and sharp. Posterior apophyse (Sp) much shorter (about half of Sa), rather oblique, tubercular, with a blunt tip. Bothridium with almost circular opening, funnel-like, with expanded rim, quite narrow, mutual distance of bothridia about 115 µm. Sensillus (Fig. 9C) about as long as distance of bothridiae (118 µm), almost fully covered by dense hairs, with only proximal 15-20% smooth. Hairs covering sensillus are longest and most dense in its distal part, creating a feeling of distally slightly expanded, club-like shape. Other prodorsal setae differing in shape and size. Interlamellar setae in and exobothridial setae exo are the shortest (40-45 µm), similarly covered by dense hairs (plumose), exo being also curved forwards and inwards. Rostral (ro) and lamellar (le) setae longer, subequal in length (105-110 µm), curved. Lamellar seta with a row of spines (Fig. 9B), rostral seta practically smooth.

Notogaster (Fig. 8A) oval, slightly elongated, with rather short, but strong and distinct spinae adnatae, oriented forwards and not curved. Notogastral setae in two longitudinal rows, slightly converging posteriad, first pair oriented forwards and the rest backwards. All setae except ps2 and ps3 of similar length (c1 being the longest - 90 µm, la 84 µm, h2 67 µm and ps1 75 µm) and shape, covered by distinct fine or squamiform spinuli and therefore appearing plumose (Fig. 9C). Two remaining setae - ps2 and ps3 similar in size and shape, shorter (34 µm, about half-length of ps1), bent forwards and smooth.

Ventral side of prodorsum (Fig. 8B, 9A) with distinct longitudinal ventrolateral ridge, framing epimeres I.

Ventrosejugal tubercles developed as a full enantiophysis, with anterior tubercle Va more distinct than the posterior Vp (Fig. 9A). Tubercles E2a and E2p present as irregular sclerotised laths, E2a connected with longitudinal ventrolateral ridge. Tectum of podocephalic fossa (tp, Fig. 9A) laterally ended by blunt or sharper angle, without protruding sharp spines. Medial pit cp not apparent. Epimeral setae smooth, differing significantly in length, 1b being apparently the longest (62 µm) Seta 1c inserted on anterior end of ventrolateral ridge, shortest of the all epimeral setae (together with 2a, about 25 µm). Discidium (dis, Fig. 8B) quite big, dentiform, oriented slightly backwards. Genital opening slightly longer (130 µm) and clearly broader (119 µm) than anal opening (length 119 µm, breadth 89 µm). Standard numbers of setae in anogenital area, setae smooth, medium long (aggenital seta ag being the longest, 41 µm).

Legs granulated as the rest of the body surface, covered by thick layer of filamentous and columnar cerotegument, relatively short. Leg I (Fig. 10A) shorter than body length (485 µm), leg IV (Fig. 10B) about 1,2 times longer than body (683 µm). Setation as usual in Kunstidamaeus , setae—especially dorsal setae of femora and genua—distinctly barbed or at least with a row of hairs or spinuli, quite long. Solenidia of leg I relatively short, even solenidion [[phi]]1 less than double-sized compared to the tibial setae, setiform.

Derivatio nominis. The name “fraterculus” means "small brother", same as was used for members of so called "Brothers Union", warriors in late phase of Czech Husite movement in 15th Century, who occupied for certain time the Spiš castle, built on the northern edge of Dreveník hill.

Remarks. Barbed sensillus and notogastral setae are quite unique within Kunstidamaeus or even Damaeus sensu lato. Some of the species have notogastral setae sparsely barbate or with small spines, but never in a way as in this new species. Bulanova-Zachvatkina (1957) described within her concept of Damaeus (Hypodamaeus) two species, which may show some similarities. As Hypodamaeus was synonymised with Damaeus (Norton, 1977; see Miko, 2006 for details), they are today placed to the nominal subgenus Damaeus s.str: D. tenuitibialis from mountains of Central Asia (Issyk-Kul Lake) and D. brevitibialis from surroundings of Moscow. According the information provided by author of description, D. tenuitibialis has all notogastral setae densely barbed, propodolateral apophysis P is developed only as a blunt angle (similarly as in K. tenuipes ), and interlamellar setae are much shorter than sensillus, which is covered by short bristles. This set of characters indicates a possible relation to Kunstidamaeus , nevertheless, no information is given on the detailed leg chaetotaxy, presence or absence of tubercles on prodorsum and on ventral side. In any case, this species differs from K. fraterculus clearly at least by absence of protruding propodolateral apophysis P and much longer legs, with by author particularly mentioned elongated tibia IV, which is about 400 um long. Damaeus brevitibialis was described on the basis of single specimen only, and the information provided by author is not sufficient again. Characteristic shape of propodolateral apophysis P suggests that it may belong to Kunstidamaeus as well. Compared to our new species, distinguishing of the species should not be difficult—the Russian species has sensillus and notogastral setae only scarcely covered by spinuli, not plumate as the new species. In addition, both D. tenuitibialis and D. brevitibialis have sensillus of different, more setiform shape. Potential placing of the two species to Kunstidamaeus will nevertheless need more detailed study on original or topotypical material.

Two other species with barbate notogastral setae were described from Central Asia: Epidamaeus (Akrodamaeus) golosovae by Lyashchev & Tolstikov (1993) and Epidamaeus johnstoni by Tolstikov (1997). Both species differ clearly by shape of sensillus and shape of notogastral setae (in both cases with flagellate ends, clearly different than in new species), and by different development of propodolateral apophyse P. Moreover, these species according the description do lack the typical character of Kunstidamaeus , the combined presence of prodorsal tubercles Ba and La.