Kunstidamaeus lengersdorfi

Miko, L. & Mourek, J., 2008, Taxonomy of European Damaeidae (Acari: Oribatida) I. Kunstidamaeus Miko, 2006, with comments on Damaeus sensu lato, Zootaxa 1820, pp. 1-26 : 6-22

Kunstidamaeus lengersdorfi (Willmann, 1932)

Synonymy. Belba lengersdorfi Willmann, 1932 Syn.: Damaeus lengersdorfi (see Sellnick 1960)

Diagnosis. Sensillus long, setiform. Propodolateral apophysis P variable: in dorsal view developed usually as strong, pointed spine, perpendicular to the body axis; may be reduced or rarely absent. Spinae adnatae strongly bent laterad and ventrad. Notogastral setae straight or only slightly bent, smooth or very weakly barbed. Setae c1, c2, la, lm, lp of approximately equal length; c1 pointing anteriad, c2, la-lp erect, directed radially from the notogaster. Legs very long, gracile; leg IV at least 1.5 times body length.

Type material examined. Collection of C. Willmann (Zoologische Staatsammlung München, Germany): 1 mounted individual, labelled " Belba lengersdorfi Willm., Harz, Hermanns-höhle VII.1933, Kosswig, det. C. Willmann". The specimen is in relatively good condition, but the embedding medium is dark and does not allow the study of details other than those given in Fig. 3. The original description (Willmann 1932) was based on two specimens from Iburger Tropfsteinhöhle (Harz, Germany) without an explicit type designation. These specimens were not found in the collection, nor were any specimens of Belba lengersdorfi var. moraviae Willmann, 1954. Therefere, we designate the studied individual as the neotype of Kunstidamaeus lengersdorfi .

Other material examined. Collection of M. Moritz (Museum für Naturkunde der Humboldt-Universität zu Berlin, Germany): Nr. 224, B-176 , Heimhelde S. - Harz: 1 mounted adult, 16.4.1968. Private collection of L. Miko (Brussels): Slovakia, Slovak Karst, Certova diera pri Domici cave , sample 218-97 , 2 adults, 23.10.1997 P. L'uptáčik lgt. Slovakia, Slovak Karst, Domica cave ( Sucha chodba - "Dry corridor") : 5 adults from alcohol trap exposed 29.4. - 13.6.1997 P. L'uptáčik lgt. Slovakia, Slovak Karst, Ardovska cave : 1 adult, 4.9.1997, P. L'uptáčik lgt. Belgium, Abime de Comblain, au-Pont (Liege B) : 1 adult, 8.10.1998 Hubart and Dethier lgt. The specimen was kindly donated to us by P. Skubała. All material unmounted, preserved in 80% ethanol. Collection of J. Mourek (Dept. of Zoology, Faculty of Science, Charles University Prague, Czech Republic): Slovakia, Slovak Karst, Ardovska cave : 1 tritonymph on decaying wood in the middle part of the cave, 8 adults on decaying wood near the cave entrance, 14.7.2004 J. Mourek lgt. ; 1 larva from a laboratory culture of J. Mourek, parental specimens collected in this cave , 14.7.2004 J. Mourek lgt. Slovakia, Slovak Karst, Certova diera pri Domici cave : 1 protonymph, 2 deutonymphs and 2 tritonymphs, about 20 m from the entrance on decaying wood, 20.5.2005 P. L'uptáčik lgt. ; 8 adults collected in the same site as the previous sample , 1.10.2005, P. L'uptáčik lgt. ; 14 adults decaying wood at the entrance lattice, 3. 10. 2005 P. L'uptáčik lgt. ; 1 protonymph, 2 tritonymphs, 5 adults, about 20 m from the entrance on decaying wood, 17. 5. 2006 P. L'uptáčik lgt. ; 1 larva from a laboratory culture of J. Mourek, parental specimens collected in this cave , 6. 4. 2007 P. L'uptáčik lgt. All material unmounted, preserved in 80% ethanol. Acarological Collections of Staatliches Museum für Naturkunde Görlitz (Germany). Nr. 04/35622 Slovakia, Slovak Karst, Ardovska cave : 3 adults on decaying wood near the cave entrance 14.7.2004 J. Mourek lgt. ; Nr. 05/35623 Slovakia, Slovak Karst, Certova diera pri Domici cave : 5 adults about 20 m from the entrance on decaying wood, 1.10.2005, P. L'uptáčik lgt. All material unmounted, preserved in 80% ethanol.

Description. Adult. Measurements. From Willmann (1932): body length 750 µm, notogaster width 450 µm. Specimen from Harz, Moritz collection: body length 740 µm, notogaster length 518 µm, notogaster width 463 µm. Material from Slovak caves: body length 730-850 µm, notogaster width 480-505 µm. For measurements of legs see Table 4.

Integument. Body colour yellowish to reddish brown. Surface of body and legs with fine granular and columnar cerotegument (Fig. 12 A,C), filamentous cerotegument present in sejugal area, on epimeres and around notogastral setae (Fig. 10 A, 11 A,B). Cuticle after the removal of cerotegument mostly smooth, apophyses and other emergent structures microtuberculate (Fig. 9). Adults often bearing exuvial scalps (gastronotic exuviae) on the notogaster but without or only with a small amount of adherent dirt.

Prodorsum (Fig. 2, 9). Short in dorsal view, length about half that of notogaster. Rostrum broadly rounded. Prodorsal setae indistinctly barbed with minute spinuli or almost smooth. Rostral (ro) and lamellar (le) seta almost equally long, but in dorsal view usually le seem longer than ro. Interlamellar seta (in) shorter, less than 1/3 of the sensillus length. Exobothridial seta fine, arched forwards. Bothridium funnel-like, with large, irregular and expanded hyaline rim. Sensillus long, setiform, straight, and slightly attenuate distally. Propodolateral apophysis in dorsal view developed as a strong, pointed spine, perpendicular to the body axis, tips only slightly or not overreaching the outline of prodorsum; in lateral view visible as a vertical ridge (Fig. 9 D). Tip of the apophysis may be reduced or rarely almost absent. Pair of short, perpendicular sclerotized elevations resembling costulae anterior to bothridia, directed mediad, not longer than diameter of bothridium. Two pairs of prodorsal tubercles well developed: Ba and La (Fig. 2, 9 B). Parastigmatic apophyses different in shape and size: Sa strong, long and spiniform, perpendicular; Sp shorter, triangular and oblique, directed more anteriad (Fig.2, 9B).

Notogaster. Broadly oval to obovate, with a pair of long, sharp and narrow spinae adnatae, bent strongly (about 90° in dorsal view) laterad and ventrad (see also in lateral view—Fig. 4 A, C); rarely with small setiform spine inserting on ventral side, unilaterally (Fig. 4 C, 9 C). Notogastral setae straight or very slightly bent, pointed, smooth or with very few minute barbs. Setae c1, c2, la, lm, lp of approximately equal length, but in dorsal view c1 appear longer and c2 shorter than others. Seta c1 directed anteriorly, setae c2, la-lp erect, directed radially from notogaster. Setae h1-h3 shorter than others, diminishing in size posteriad. Posterior notogastral setae ps1-ps3 very thin, finer than h1-h3 (Fig. 4 A, B).

Ventral region. Ventral setation as usual for Damaeidae (Grandjean 1960; Norton 1977b): epimeral setal formula (from epimere 1 to epimere 4): 3-1-3-4; genital g: 6; aggenital ag: 1; anal an: 2; adanal ad: 3. Ventral setae quite long, fine, setiform, at least partly with indistinct barbs, usually bent. Tectum of podocephalic fossa ending as a blunt tip, ventrally with three well developed lamellae (Fig. 2 C, 10 B). Medial pit cp on coxisternum I well developed, open anteriad. Propodoventral tubercles E2a and E2p weakly developed, usually as short, dentate or tuberculate sclerotised ridge. Ventrosejugal tubercle Va large, strong, dentiform, Vp weakly developed, in light microscope sometimes discernible only in lateral view (Fig. 2, 10 B). Tubercle E2p and Va laterally connected by a longitudinal ridge. Discidium of variable shape, usually developed as small, sharp tubercle pointing laterad, slightly anteriad or slightly posteriad (Fig. 2D).

Legs (Fig. 5, 6). Legs monodactylous, gracile and long, both first and fourth pairs longer than body: leg I: 815 µm, length of leg IV: 1 100 µm in measured individual (Harz, Germany, Moritz collection); leg IV at least 1.5 times body length. Willmann (1932) gives lengths of legs I: 810 µm, II 650 µm, III 750 µm and IV 1010 µm. In our material from the caves of Slovak Karst maximal lengths were as follows: leg I 855 µm, II 700 µm, III 955 µm and IV 1270 µm. Legs I and II were measured without trochanter, whereas legs III and IV were measured with trochanter. For detailed measurements see Tab 4. Setal formulas of legs as follows (from trochanter to tarsus, famulus included, solenidia not included): I: 1-7-4-4-20; II: 1-6-4-4-17; III: 2-4-3- 3 -17; IV: 1-4-3-3-14. Solenidia of tibia and tarsus I and tibia IV very long, tactile. Solenidia of genua I-III with companion seta d, all genual solenidia shorter than their companion setae. Leg chaetotaxy of all developmental stases as presented in Table 2 and 3. Famulus normal, emergent in adults.

Remarks. In some populations from Slovak caves the forms with very small or completely reduced tips of propodolateral apophysis P were found together with typical specimens (Fig. 2 B). This rather unusual variability shows that development of the propodolateral apophysis may not have as important role at the generic level as usually believed.

The peculiar setiform spine, asymetrically present on one spina adnata in two examined specimens, may represent atavistic reappearance of notogastral seta c3 (Norton pers. comm.), which is normally absent from adults of Damaeidae . Similar setiform spines on spinae adnatae were noted in Epidamaeus tenuissimus Hammer , 1967 and E. tritylos Behan-Pelletier and Norton, 1983 (see Behan-Pelletier & Norton 1985).

Ontogeny. Drawings and SEM micrographs of tritonymph are in Fig. 7, 8, 10, 11 and 12. The following description applies to all immature stages unless otherwise specified.

Measurements. See Table 4.

Integument. Body cuticle colourless to pale yellowish. Legs, epimeres and prodorsum slightly more sclerotised. Entire body including legs and most of the setae covered by cerotegument with granular sculpture, uniform throughout, no filamentous elements present; slightly more distinct in tritonymph. Two sizes of granular elements distinguishable: macrogranules (1-2 µm in diameter, visible in light microscope) of spherical or nearly spherical shape with granulated surface, irregularly distributed and separated by more than their diameter; microgranules (0.2 µm or less in diameter, invisible in light microscope) of irregular shape, spaced much more densely than macrogranules. Loose growth of fungal hyphae or of other filamentous microorganisms often present on body surface.

Prodorsum. Relatively short, about half-length of gastronotic region in lateral view. Rostrum broadly rounded. Pair of distinct horizontal ridges (similar to tutoria of adults in some poronotic families) present laterally, above acetabula I (Fig. 7, 8). All prodorsal setae (except for nymphal in) with short barbs. Setae ro and le comparatively long, but ro distinctly shorter and slightly thinner than le; both arched mediad and ventrad. Larval seta in comparatively long, barbed, erect, directed posteriad, inserted on minute apophyses. Nymphal in (Fig. 7 C) short, strong, smooth with blunt and slightly swollen tip, erect, directed posteriorly, inserted on minute apophyses. Sensillus long, attenuate with fine tip, barbed in distal 2/3. Seta ex very short, directed anteriad (Fig. 7 C).

Gastronotic region. Larva more or less truncate posteriorly, nymphs rounded or slightly tapered with apophyses bearing setae h1. Anterior margin, bearing setae c1, c2, c3, distinctly elevated, cuticle behind this setal row folded (Fig. 8, 10 C). Ontogeny and distribution of gastronotic setae similar to that of other Damaeidae (cf. Grandjean 1954a; Norton 1977b, 1978a, 1979c; Norton & Ryabinin 1994): Seta h3 vestigial in larva. Setae ps1, ps2, and ps3 appear first in protonymph. All nymphs and adults lack setae da, dm, dp. Seta c3 is absent from adult. Gastronotic setae pigmented light brown with hyaline base, finely barbed with small spinuli; inserted on small sclerites (only weakly defined in larva and protonymph) with more or less developed apophyses. Sclerites of nymphal ps2 and ps3 minute and hardly visible. Setal pair c1 inserted very close together on unpaired anterior sclerite. Setal pairs h1 and ps1 inserted on common unpaired posterior sclerite (Fig. 7, 8). Nymphal setae c1, c2, la, lm, lp, h1, h2, h3 long, comparatively strong and erect, with long, flagellate tips (often broken); seta c3 short and thinner. Seta ps1 very thin, comparatively long; ps1> ps2> ps3.

Cornicle k narrow, long, erect, slightly S-shaped, with pointed tip directed anteriad (Fig. 7 A, 8, 10 D). Gastronotic exuviae loosely attached to notogaster, arranged in pyramidal shape with highest point approximately in middle of gastronotic region (Fig. 10C). Cuticle of gastronotic exuviae distinctly reticulated, almost clean or with a small amount of debris or fungal hyphae.

1) in one tritonymph 21 (2) setae were observed on right tarsus I (setal homology discussed in the text)

2) in one tritonymph 16 setae were observed on right tarsus III (setal homology discussed in the text)

Ventral region. Setae of infracapitulum indistinctly barbed on one side, or smooth. Epimeral setal formulas as follows: larva: 2-1-2; protonymph: 3-1-2-1; deutonymph: 3-1-2-2; tritonymph: 3-1-3-3; adult: 3-1-3-4. Larval seta 1c (not included in the epimeral larval formula) similar to other Oribatida - scale-like, covering the Claparède’s organ. Epimeral setae finely barbed on one side, some with very few minute spinuli or smooth. Cuticle of anogenital region weakly folded. Ontogeny of setal formulas in anogenital region typical of the family (see Norton 1977b): from larva to adult as follows: aggenital ag: 0-0-1-1-1; genital g: 0-1-3-5-6; pseudanal ps: 0-3-3-3-3; adanal ad: 0-0-3-3-3; anal a: 0-0-0-2-2.

Legs. Legs of all stases long, gracile (see Fig. 10A). For detailed measurements see Table 4. Leg IV is longest and leg II shortest, with difference most pronounced in adult. Leg IV exhibits positive allometric growth: 1.14-1.20 times body length in tritonymph, but over 1.5 times body length in adult.

Leg setae comparatively long, thin, most are distinctly barbed. Ontogeny of setation e given in Table 2, detailed ontogeny with homologies of setae given in Table 3. Variations in leg setation are described in Remarks. Famulus s minute, sunken in a sclerotised cup in all immature stases, as typical for most members of Damaeus sensu lato (Norton 1977a, 1977b; 1979b). Ontogeny of solenidiotaxy normal for family (Norton 1977a).

Remarks on the ontogeny. The knowledge of ontogeny in Damaeidae is still fragmentary. Leg chaetotaxy seems to offer the most relevant characters. Individual asymmetrical setal variation on tarsus I (see Fig. 5 E) and III in tritonymphs and on tarsus IV in adults was observed. In one tritonymph three additional setae were found on the right tarsus I (see Fig 5E). One of them can be homologised with Ny1' (normally appearing in adult), but homology of the remaining two setae is unknown. In another tritonymph one additional seta on tarsus I was found, probably also homologous with Ny1'.

We were not able to define any immature characters distinguishing Kunstidamaeus from Epidamaeus , except for differences in famulus development in E. tatricus (Mourek & Miko in press). From the nomenclatural point of view, a major problem is the inaccessibility of the type species Epidamaeus bituberculatus (Kulczynsky, 1902) and therefore the lack of any information on its immature morphology. Moreover, until present, ontogenetic data are available only for K. lengersdorfi and a few species of Epidamaeus . Ontogeny of the leg chaetotaxy in K. lengersdorfi is identical with the Nearctic species Epidamaeus (Akrodamaeus) longiseta (Banks, 1906), redescribed by Norton (1978a). Therefore, we consider the removal of Akrodamaeus from Epidamaeus to Metabelbella Bulanova-Zachvatkina, 1957, proposed by Subías (2004) as unjustified. Even the scarce knowledge of ontogeny in Epidamaeus indicates interspecific variation within the genus. For example, Epidamaeus (Epidamaeus) tatricus (Kulczynski, 1902) differs from both former species in several details: Ny' on femur III is tritonymphal (adult in K. lengersdorfi ); Ny' on genu IV is tritonymphal (deutonymphal in K. lengersdorfi ); Ny" is added on femur IV and on genu III + IV in adult (Mourek unpubl.); and the famulus is emergent in all stases (Mourek & Miko in press). Norton (1977a) analysed the setation of three undescribed species of Epidamaeus , in two of them Ny' on genu IV was tritonymphal (as in E. tatricus ). On the other hand, Kunstidamaeus lengersdorfi and all mentioned Epidamaeus species share several differences in ontogeny of the leg setation from Damaeus (including Adamaeus and Paradamaeus ) and Spatiodamaeus (see Norton 1977a, 1977b):

1. Seta Ny' on trochanter IV is tritonymphal instead of deutonymphal. The former character state can be found also in some other Damaeidae , e.g. in Belba corynopus .

2. Seta l' on femora I and II is deutonymphal (as in most other studied genera of Damaeidae ) instead of protonymphal.

3. Seta Ny' on genu III is deutonymphal instead of protonymphal.

4. Ventral accessory seta Ny1' on tarsi I-IV appears in the adult instead of the tritonymph.

5. Ventral accessory seta Ny1" is absent from all tarsi (as in other genera of Damaeidae except Damaeus and Spatiodamaeus ), instead of being present in the adult.

These differences support the separation of Kunstidamaeus from Damaeus and Spatiodamaeus , but knowledge of ontogeny in more species of the former genus is needed. The shared character states in setation of Kunstidamaeus and Epidamaeus are probably plesiomorphic within Damaeidae (cf. Norton 1977) and do not imply the monophyly of the Kunstidamaeus - Epidamaeus clade. Therefore they are not in conflict with the proposal of Kunstidamaeus as a separate genus, which is based on adult morphology.

Ecology, geographical distribution. The species has been found only in caves or in cave entrances, usually on organic debris such as bat guano, rotten wood or even old candle paraffine ( L'uptáčik & Miko 2003; L'uptáčik unpubl). Probably, the species is a true troglobiont (Lebrun 1967) or at least troglophile ( L'uptáčik & Miko 2003). The nominate form was described from the cave "Iburger Tropfsteinhöhle " in Harz, Germany (Willmann 1932). Kunstidamaeus lengersdorfi is also known from caves in Slovak Karst, Slovakia ( L'uptáčik & Miko 2003). It was also recorded in caves in Belgium (Willmann 1935; Hubart and Dethier unpubl.), French Jura, France (Willmann 1938) and Germany (Griepenburg 1939). Kunstidamaeus l. var. moraviae as well as the nominate form were reported from caves of Moravian Karst in southeast of the Czech Republic (Willmann 1954; see Remarks). The occurence of K. lengersdorfi in further European karstic cave systems can be also expected. It is probable that the species occurs in Hungarian caves of Aggtelek that are interconnected with the cave system of Slovak Karst.

Remarks: Willmann (1954) described " Belba lengersdorfi var moraviae ", slightly different from the nominal form, based on specimens from a cave in Moravian Karst (now in the Czech Republic). Kunst (1968) regarded this form as a valid subspecies, taking into account specific habitat (caves) and geographical separation of populations from Harz and Moravia. However, Willmann (1954) reported the nominal form from other caves in Moravian Karst as well. Morphological differences are very slight - " Belba lengersdorfi var. moraviae " has according to Willmann (1954) finer and more curved notogastral hairs, the anterior four pairs (c1- lm) being distinctly longer than the rest. Most of our Slovak specimens are closer to the "Moravian variety" or have intermediate form, but specimens very similar to the nominate form were also found. Notogastral setae have different lengths also in the specimen from Harz (Moritz Collection; see Fig. 1). Since the Moravian form was described from only two individuals, and variability of the species was not sufficiently studied, the status of the Moravian form is equivocal. For now, we treat all individuals as belonging to one taxon - Kunstidamaeus lengersdorfi .