Chaleponcus Attems, 1914

Enghoff, Henrik, 2014, A mountain of millipedes I: An endemic species-group of the genus Chaleponcus Attems, 1914, from the Udzungwa Mountains, Tanzania (Diplopoda, Spirostreptida, Odontopygidae), European Journal of Taxonomy 100, pp. 1-75 : 8-9

Genus Chaleponcus Attems, 1914

This genus was established by Attems (1914) for three new species, of which C. limbatus Attems, 1914 , was subsequently designated as type species by Kraus (1960).

Chaleponcus was treated in detail by Kraus (1960, 1966) and was recently addressed by Frederiksen (2013a). Vohland & Hamer (2013) redescribed two Chaleponcus species from Namibia. From the works of these authors the following diagnosis of Chaleponcus can be extracted, based entirely on gonopod structure, using the terminology suggested by Frederiksen (2013a,b; Frederiksen & Enghoff 2012) and emended in light of the species described here:

Prionopetalini in which

• the proplica and metaplica of the gonopod coxa come together apically and form a hoodlike structure, here termed cucullus

• the solenomere is very long, whiplike, at least twice as long as the telomere if stretched out, not spiralled terminally, and without accessory branches or outgrowths (except for sometimes at the very base, corresponding to the “Tibialdorn” of Kraus; see species descriptions)

• the telomere is proximally folded like a tube or a trough and distally separates into two or three diverging lamellae

Kraus (1960, 1966) included 19 species in Chaleponcus , distributed in southern African as far north as Zimbabwe and southern Mozambique, and Frederiksen (2013a) added a 20 th species from northern Tanzania. Kraus (1960, 1966) did not include Chaleponcus dabagaensis Kraus, 1958 , described from the Udzungwa Mts (not W Usambaras as stated by Frederiksen 2013a); this species Kraus (1960) excluded from the genus and tentatively assigned to another predominantly S African genus, Spinotarsus Attems, 1909 . In fact, he described the species as Chaleponcus (Storthoporus) dabagaensis , and as he (1960) listed Storthoporus Attems, 1928, as a synonym of Spinotarsus , the transfer seemed logical. However, C. dabagaensis lacks most characteristics of Spinotarsus , including a spiny proximal lamella on the telomere and the strongly sclerotized lamella (“Bogenlamelle”) on the posterior surface of the telomere. C. dabagaensis does have a trait seen in many Spinotarsus species, viz., the longitudinally fluted solenomere; this is a character not seen in other previously described Chaleponcus species but found in most of the species described here. C. dabagaensis also has the spine-bearing shelf, see below, and without doubt belongs together with the other Udzungwan species treated in the present paper. I here reallocate it back to Chaleponcus .

The Udzungwa species described here and referred to Chaleponcus differ from their congeners in one conspicuous character, the spine-bearing ‘shelf’ on the gonopodal coxal metaplica. Many odontopygids have spines in various positions on the gonopod coxa, including the subdistal position on the metaplica where the spine-bearing shelf is situated in the Udzungwan species. This is, e.g., true for Chaleponcus parensis Frederiksen, 2013 , Prionopetalum bifidum VandenSpiegel & Pierrard, 2009 , Patinatius attemsi Kraus, 1960 , P. bidentatus Kraus, 1960 , Spinotarsus viridis Kraus, 1966 , Allantogonus spp. ( Kraus 1960, Attems 1935), Kompsoprium spp. ( Kraus 1960, Attems 1935) and Odontopygista natalica Kraus, 1960 . In all these species except one, however, the spine is not associated with a shelflike structure and are most likely not homologous with the ‘shelf-borne’ spine in the Udzungwan species. The exception is Spinotarsus viridis , where the spine does seem to originate from a horizontal shelf ( Kraus 1966: fig. 350); in other characters, however, S. viridis is a typical Spinotarsus .

Based on the probably autapomorphic spine-bearing shelf and the longitudinally fluted solenomere, a species group can be defined for the Udzungwan species of Chaleponcus . Following tradition, the group is named after the first described species in the group and hence will be named the Chaleponcus dabagaensis group.