Dolicheremaeus mahnerti, Mahunka & Mahunka-Papp, 2009

Mahunka, S. & Mahunka-Papp, L., 2009, New and little known oribatids from Kenya, with descriptions of two new genera (Acari: Oribatida), Journal of Natural History 43 (11 - 12), pp. 737-768 : 747-749

Dolicheremaeus mahnerti sp. nov.

Diagnosis

Rostrum rounded. Lamellae long, their apices reaching over the insertion of lamellar setae. Sensillus long, basal part dilated, distal part setiform, long and bent. Two pairs of prodorsal and two pairs of notogastral dorsosejugal condyles present. Ten pairs of long notogastral setae observable, varying in length, some of them flagellate. Epimeral setae normal, comparatively long. Surface of genital plates smooth. Anal and adanal setae very long, also flagellate. Types of the ultimate setae (u) of the legs: L-S-S-S ( Aoki 1967).

Material examined

Holotype Kenya, Tana River district, 10 km north of Garsen , 23 October 1977. Leg. V. Mahnert and J.-L. Perret (G-77/31). Ten paratypes from the same sample . Holotype and five paratypes: MHNG, five paratypes: (1729-PO-2007): HNHM .

Measurements

Length of body 692–914 Mm, width of body 332–414 Mm.

Prodorsum

Rostral apex round, its surface smooth. The whole prodorsal surface also nearly smooth, only some granulate fields observable along the basal part of the lamellae, and a pustulate exobothridial part also visible. Lamellae very long and narrow, their anterior part bent inwards. Distal apices reaching over the insertions of the lamellar setae ( Figure 5A ). Both pairs of prodorsal condyles distinct, median ones rounded, lateral ones slightly angular (?) ( Figure 5C ). Rostral and lamellar setae simple, setiform, strongly ciliate (setae le), or barbed (setae ro). Interlamellar setae comparatively short, ending far from the insertion of lamellar setae. Exobothridial setae much shorter, simple. Sensillus peculiar in shape, long, with a dilated basal part bearing a long distal cilium, bent backwards and inwards ( Figure 5D ).

Notogaster

Surface smooth. Two pairs of well-developed condyles present, median pair rounded, lateral pair simple and flat. Ten pairs of mostly very long notogastral setae, greatly varying in length. All setae well ciliate at basal part ending in a long, filiform distal part. Setae c 2 shortest, setae p 1 slightly shorter than p 2. Lyrifissure ips located between setae p 3 and h 3.

Lateral part of podosoma ( Figure 5D )

Tutorium weak, hardly observable. Lateral lamelliform expansion long, arching upwards, directed towards and reaching the insertion of rostral setae. Pedotecta 1 narrow, pedotecta 2-3 rectangular in lateral view. Sejugal region pustulate.

Ventral parts ( Figure 5B )

Shape of the apodemes and epimeral borders typical for the genus, but the posterior border of this region (bo.4) weak, barely visible. Great differences among the epimeral setae, setae 1c, 3b, 3c, 4c and 4b conspicuously long, 1a, 2 a, 3a and 4a much shorter. Surface of the ventral plate nearly smooth, along the margin of the ventral plate some weak foveolae. Genital plate smooth. Anterior pair of the genital setae shorter than the others. Adanal setae also very long, flagellate, similar to the notogastral ones. Setae ad 3 arising close to the lateral margin of the ventral plate, setae ad 1 in adanal position. Lyrifissures iad stand near the anterior corner of the anal opening. Aggenital, anal and adanal setae partly pilose, all filiform distally.

Legs

Types of ultimate setae (u): L-S-S-S. Tarsi of all legs without teeth.

Remarks

The survey of the Ethiopian species of this genus was completed by Wallwork (1961, 1962), Aoki (1967) and Balogh and Balogh (2002). The new species belongs to a species group which can be characterized by the well-developed, rounded median condyles (co.pm. and co.nm.), the mostly very long and flagellate notogastral setae and the similar adanal setae. It stands nearest to Dolicheremaeus africanus ( Wallwork 1962) and Dolicheremaeus csuzdii Mahunka et Mahunka-Papp, 2007 ; however, it is distinguished from D. africanus by the ratio of the lengths of prodorsal setae to notogastral setae (e.g. r 2 very short in D. africanus ), and by the striate genital plates (smooth in D. africanus ) and from D. csuzdii by the smooth dorsal and genital surface and by the much longer adanal setae (short in D. csuzdii ). The new species is also distinguished from all congeners by the peculiar shape of the sensillus.

Etymology

We named the new species in honour of our friend Dr V. Mahnert, the former director of the Museum D’Histoire Naturelle Geneva and the collector of this very rich and interesting material.

Figures

Figure 5. Dolicheremaeus mahnerti sp. nov. (A) Body in dorsal view, (B) body in ventral view, (C) basal part in prodorsum in dorsal view, (D) prodorsum in lateral view.