Koponenius gen. nov.

Name: Honours Seppo Koponen, a prominent colleague arachnologist from Turku University, Finland, on the occasion of his 70th birthday; masculine in gender.

Diagnosis: Differs from the other 6 known haplodesmid genera by only 19 body segments in both sexes, combined with a rather pyrgodesmid-like body shape and a special ozopore formula (5, 7–18), ozopores being borne on porosteles, as well as 4 transverse rows of setigerous isostictic tubercles per postcollum metatergum and a clearly helicoid, twisted prefemoral portion of the gonopod so that the seminal groove runs mostly laterally, not mesally (see also Key below).

Description: Body with 19 segments in both sexes, subcylindrical, not capable of volvation. Head, collum and following metaterga clothed with a dense cerategument. Ozopores borne on simple porosteles, pore formula 5, 7–18. Collum relatively large, sometimes covering the head from above. Paraterga 2 considerably enlarged, but not so as to ensure complete volvation, instead subtending the head laterally. Each postcollum metatergum usually with 4 transverse rows of isostictic setigerous tubercles. Telson strongly flattened dorsoventrally, subtruncate at tip, fully concealing a small epiproct tip from above. Spiracles seem to be absent.

Gonopods of a facies rather typical of Haplodesmidae, in situ both held nearly parallel to each other: coxae elongate, non-globose, subcylindrical, both well fused anteromedially, each carrying an elongated cannula on mesal face; telopodites elongated, slender, each clearly subdivided into an elongated, clearly helicoid, twisted prefemoral (= densely setose) part on which the seminal groove runs mostly laterally, not mesally; acropodites curved caudad, slender, uni- or biramous; seminal groove borne on a long solenomere, terminating apically, devoid both of an accessory seminal chamber and a hairy pulvillus.

Type species: Koponenius unicornis sp. nov.

Other species included: Koponenius biramus sp. nov.

Remarks: The family Haplodesmidae hitherto contained six genera. Most of them can be conveniently divided into two morphological groups: (1) The “haplodesmid” type usually shows ozopores borne on special, mostly boletiform porosteles or tubercles, while paraterga are absent from body segment 3 onwards, and (2) The “doratodesmid” type is normally devoid of porosteles, whereas the paraterga are present on all segments, often ensuring complete volvation (Golovatch et al. 2009a).

Koponenius gen. nov. seems to be especially similar to Prosopodesmus Silvestri, 1910, likewise being intermediate between the two groups described above in showing quite strongly developed paraterga, coupled with the presence of porosteles. However, all 7 known Prosopodesmus species (mostly native to tropical Australia, but a few to southern Japan) are considerably more pyrgodesmid-like in body shape, the collum being strongly flabellate, its fore margin 12-lobulated, covering the head from above. In addition, they have 20 body segments, only 3 transverse rows of isostictic tubercles per postcollum metatergum, varying pore formulas, but not (5, 7–18), usually mushroom-shaped porosteles, and the seminal groove on falcate and unbranched gonopod telopodites which runs only on the mesal side and is typically supplied with a hairy pulvillus near its orifice (Mesibov 2012). The above similarities between these two genera are also reflected in an updated key which concludes this paper.