Lipseuma, Golovatch & Geoffroy & Mauriès, 2006

Golovatch, Sergei I., Geoffroy, Jean-Jacques & Mauriès, Jean-Paul, 2006, Four new Chordeumatida (Diplopoda) from caves in China, Zoosystema 28 (1), pp. 75-92 : 85-86

Genus Lipseuma n. gen.

TYPE SPECIES. — Lipseuma josianae n. sp.

ETYMOLOGY. — Dedicated to Josiane et Bernard Lips, -euma being a common generic end suffix in Chordeumatida . Gender neuter.

OTHER SPECIES INCLUDED. — Lipseuma bernardi n. sp.

DIAGNOSIS. — Differing from both other genera of Kashmireumatidae , Kashmireuma Mauriès, 1982 and Vieteuma Golovatch, 1984 , as follows:

– a completely unpaired, undivided colpocoxite of anterior gonopods (male leg-pair 9) (versus paired, fully or partly independent in the other two genera);

– posterior gonopods (male leg-pair 9) unusually simple, telopodite voluminous but 1-segmented (versus strongly differentiated and 2-segmented, regardless of a vestigial segment 3 sometimes visible in the other two genera); – male legs 6 particularly strongly hypertrophied in relation to any other leg-pair (versus normal to moderately incrassate male legs 3-6(7) in the other two genera);

– normal female legs 2 (versus normal or vestigial in the other two genera);

– bursa of vulva particularly short and wide (versus elongate in the other two genera).

REMARKS

The small Oriental family Kashmireumatidae has hitherto been known from six species, three each in Kashmireuma (Himalayas of India and Nepal) and Vieteuma ( Vietnam and southern China). With the addition of two species of Lipseuma n. gen., it becomes possible to better outline the genera included in the family.

Shear (2002) has recently provided a brief summary concerning the main traits distinguishing all six kashmireumatid species known to date. These are Kashmireuma nielseni Mauriès, 1982 , from Kashmir, India; K. schawalleri Shear, 1987 and K. nepalense Mauriès, 1988 (nom. emend. pro nepalensis), both from Nepal; Vieteuma topali Golovatch, 1984 , from North Vietnam; V. hubeiense Mauriès & Nguyen Duy-Jacquemin, 1997 (nom. emend.pro hubeiensis), a troglobite from Hubei Prov., China; and V. longi Shear, 2002 , from Yunnan Prov., China ( Mauriès 1982, 1988; Golovatch 1984; Shear 1987, 2002; Mauriès & Nguyen Duy-Jacquemin 1997). The main differences between Kashmireuma and Vieteuma are as follows:

– Vieteuma has the posterior gonopods placed on a thick plate-like sternum, but telopoditomere 1 is very strongly modified, supplied with conspicuous lobes/outgrowths, versus sternite almost absent medially, but telopoditomere 1 only slightly modified in Kashmireuma ;

– Vieteuma has 26 or 28 body segments, versus 28 in Kashmireuma ;

– Vieteuma has female legs 2 normal or vestigial, versus vestigial in Kashmireuma .

As one can see, the above distinctions are relatively shaky, with only the posterior gonopod structure so far serving to reliably separate these still oligotypic genera. When more kashmireumatids become known, it is possible that Vieteuma will have to be sunk as a synonym of Kashmireuma .

The characters distinguishing Lipseuma n. gen. appear to be much stronger, especially the unusually simple anterior and posterior gonopods. In fact these are the simplest among the Chordeumatida . However, in no way can Lipseuma n. gen. be regarded as basal within the family in relation to Kashmireuma and Vieteuma . The gonopods of Lipseuma n. gen. species are simple, but the new genus itself is evolutionarily advanced. This situation resembles that observed in the North American genus Pseudotremia Cope, 1869 , in which several species highly troglomorphic in body form show strongly simplified gonopods. The simplification results most probably because of isolation in caves, which removes any selective pressure. Indeed, the anterior gonopods of Lipseuma n. gen. species show a complete fusion of the colpocoxites, these being fused only partly (parabasally) in Kashmireuma nepalense and entirely free in the other species of the family. Further apomorphies of Lipseuma n. gen. include telopoditomere 2 of the posterior gonopods being totally suppressed, and the vulvae very strongly transverse. The same holds for the hypertrophied and very special male legs 6, which apparently serve the male as claspers during copulation.