Hypogeoppia dungeri, Schwalbe, T., 1995

Schwalbe, T., 1995, Hypogeoppia dungeri, a new species of the Oppiellinae (Acari, Oribatida, Oppiidae), Abhandlungen und Berichte des Naturkundemuseums Görlitz 68, pp. 27-32 : 27-32

Hypogeoppia dungeri sp. n.

Types: Holotype: 1 female (soil core, between 5 cm and 10 cm depth) and 20 paratypes in glycerol are deposited in the oribatid collection of the Staatliches Museum für Naturkunde Görlitz, Saxonia

Locus typicus: Germany, Neisse valley near Goerlitz , from a soil core, taken in a spruce plantation, 21st April 1988, in glycerol preserved, leg. H.-J. Schulz.

Diagnosis

Size 210 µm; colour yellowish brown; 1 pair of approximately reverse u-shaped apophyses on the anterior border of notogaster; tri-dentated rostrum; 5 pairs of genital setae; reticulated epimerae 3 + 4; setae 3b + 4b divided + 4c ramified on lateral tip of discidum.

Description

Measurements: length 210 µm (200 µm [3 females, 1 male], 205 µm [2 females], 210 µm [17 females], width 100 µm).

Colour: yellowish brown.

Cuticle: dorsal region smooth, epimeral region: epimerae 3 + 4 reticulated with a meshlike network of large polygonal patterns (meshes 10 µm), epimer III laterally with small transparent nodules.

Prodorsum: shorter than hysterosoma (0,8 x length of notogaster); rostrum tri-dentated with tapering triangular rostral teeth, rostral incisions relatively wide; all prodorsal setae setiform, exobothridial setae comparatively very long (2,75 µm), interbothridial setae short, all the other prodorsa: setae medium long; lamellar costulae (1,5 µm long) s-shaped with the lower curve covered by a chitinous membrane. The lamellar setae arising from a chitinous sclerit; interlamellar crests originate from the bothridium but do not meet the lamellar costula directly. The short interlamellar setae in sert on the propodosoma beneath the lower end of the costulae; the very long glabrouse exobothridial setae insert on strongly developed apophyses lateral in front of the bothridium and run parallel to the crest towards the lamellar costulae (flg. 3a). The pectinate sensilli have 7-8 long branches and sit in normal oppiid bothridia. The knoblike interbothridial ridges are connected transversally by a chitinous plica; that is the anterior part of the sejugal enantiophysis.

Notogaster (fig. la): On the anterior border one pair of reverse u-shaped apophyses, shape is variable; notogaster convex; with 10 gastronotic setae inserting in 2 somewhat parallel longitudinal rows The first 3 pairs of setae in ta - te - ti position. The upright setae ta inserting lateral to the apophyses, and inside of lyrifissures ia on the anterior border of notogaster. Setae ta medium long, smootl and bend sideways after the first fifth of its length. Setae r3 are the longest gastronotic setae, straight projecting sideward. Four pairs of lyrifissures are recognizable on the notogaster. Lateral aspect: acaetabulae I-III at the same level, acetabula IV displaced a bit towards the lateral border of notogaster, dorsal sejugal furrow drop-shaped.

Epimeral region (fig. 1b): epimeral chaetotactic formula 3-1-3-3, Epimerae 1 and 2 smooth, epimerae 3 and 4 reticulated in a large polygonal mesh-like network (meshes 10 um), epimera 3 with small transparent nodules. Epimeral setae 1c insert on a separate chitinous ridge, 4a insert on the border of apodema 4. Apodema 4 only weakly sclerotised. Epimeral setae 3b and 4b divided, 4c insert on the tip of discidium and is ramified.

Anogenital region (fig. lb): one pair of adgenital setae in central position between oval genital (length: 2,2 -2,5 µm) and anal plates (length: 3,5 - 3,75 µm). Five pairs of genital setae, g1 being somewhat longer than the other genital setae; anal plates with two pairs of anal ones, three pairs of adanal ones; setae ad3 anterior to the front border of anal plates and very minute. A distinct variability exists in this species. Especially the reverse u-shaped apophyses vary a bit in their shape, as does the excision between them.

Affinities

This species probably has to be inserted into the genus Hypogeoppia , because all by SUBIAS (1981) given features fit and there are a lot of similarities with the members of this genus. But the definition of Hypogeoppia is still uncleared and a more detailed study with a following redescription is in need. Especially much similarities exist with Hypogeoppia hypogeum (Paoli, 1908), I refer to the redescription by MAHUNKA (1966) and two specimens, I kindly got from his collections. Hypogeoppia hypogea , which has a naso only, its rostrum is not really tridentate, has a size of 287 - 315 µm and, no one pair of apophyses at the anterior part of notogaster. At the specimens I got for examination, there were the lamellar costulae with the lower curve covered by a chitinous membrane too. The interlamellar setae seemed to be very long, just reaching the anterior border of notogaster. In his redescription MAHUNKA (1966) writes:

"Rostral apex pointed, prodorsum with characteristically shaped lamella, lamellar hairs arising in their apices, strongly ciliate. Interlamellar hair also ciliate. Exostigmatal hair also very long, flagelliform. Sensillus broadening, slightly falcate, external margin with 6 - 8 thin lateral branches. A characteristically shaped excision on anterior margin of notogaster. This latter with 10 pairs of hairs, all of equal length, thin."

At Hypogeoppia terricola Subias, 1981, H. festoneata Moraza & Moreno, 1988 and Hypogeoppia terricola salamanticensis Morell-Zandalinas, 1987 there are two pairs of tubercels at the anterior border of notogaster. Hypogeoppia terricola and Hypogeoppia festoneata seem to me to be a single species, since their epimeral setae 3b and 4b are divided as well, the epimerae 3 and 4 reticulated with a mesh-like network of large polyform shapes, so the only difference is in size (0,21 mm versus 0,24 mm). This is thus a new synonym ( syn. n.). Hypogeoppia exempta (Mihelcic, 1959) also posseses one pair of tubercels at the anterior border of the notogaster, but is larger (300 µm) and lamellar costulae are divided with the lamellar setae standing directly on the proterosoma and the rostral setae insert on a crest originating from the lamellae. The sensilli are round with 6 rami, the innermost being the shortest. At the original description, the exobothridial setae also seem to be long.

From the genus Berniniella , the species Berniniella sigma (Sellnick, 1951) is the most similar one, explaining its having been previously placed in the genus Hypogeoppia . The similarities with B. sigma are the following: the tridentate rostrum with very similar points of insertion of rostral setae, some nodules above acetabulum 3 with a mesh net of oval to polyform meshes on the posterior epimeral region, and the size (210 µm). On the prodorsum there further are to be mentioned the

lower bows of the lamellar costulae covered by a chitinous membrane, and not at least, the pedipalpus with its 7 tarsal seate. In H. dungeri , however, the pedipalpal tarsus has a distinct solenidium.

Very similar to Berniniella sigma is also Oppiella signata Schwalbe , 1989. It does not belong to Oppiella (Oppiella) sensu Subias & P. Balogh, 1989, is really intermediate between Berniniella sigma and Dissorhina ornata (hence the name). The sensilli, which are very similar to H. dungeri resemble to Berniniella sigma . The lamellar setae insert on separate chitinous sclerits and are poorly developed. This species has 5 genital setae, with g1 being the longest, like it is in species of Dissorhina and Hypogeoppia . Rostral setae at Oppiella signata insert near to each other on a small naso like in the genus Dissorhina and the anterior margin of notogaster is with a median protruding chitinous plate, as well as Dissorhina tricarinatoides (Dubinina et al. 1966). Dissorhina tricarinatoides (Dr. Miko kindly sent me some drawings) has pectinate sensilli and is very similar to Opiella signata , but it does not have costulae, its rostral setae insert very near to each other on the anterior half of a somewhat rhombic naso. Because of the poorly developed setae ta (c2), the rostral setae near to each other on a small naso and the same shape of sensillus like Dissorhina tricarinatoides (see: SUBIAS & P. BALOGH, 1989: 377) Oppiella signata has to be inserted to the genus Dissorhina : Dissorhina signata n. comb.

Derivatio nominis

I dedicate the new species to my esteemed teacher in soil biology Prof. Dr. Wolfram Dunger, who celebrated his 65th birthday in October 1994.