Geotypodon, Enghoff, 2016

Enghoff, Henrik, 2016, A mountain of millipedes III: A new genus for three new species from the Udzungwa Mountains and surroundings, Tanzania, as well as several ‘ orphaned’ species previously assigned to Odontopyge Brandt, 1841 (Diplopoda, Spirostreptida, Odontopygidae), European Journal of Taxonomy 177, pp. 1-19 : 6-8

Geotypodon gen. nov.

urn:lsid:zoobank.org:act:54706BDE-AF06-42BC-A2B3-F2D23A097B28

Type species

G. millemanus gen. et sp. nov.

Diagnosis

A genus of Odontopygidae-Prionopetalini characterized by: a long basad metaplical spine on the anterior side of the coxa, a compact torsotope, lack of pretorsal or torsal spines/processes, a pronounced posttorsal narrowing without spines, a division of the telopodite into solenomere and telomere immediately distal to posttorsal narrowing, a spine emerging from the base of the telomere and curving more or less parallel to the basal parts of the solenomere, a slender, whip-like, smooth solenomere without any outgrowths or appendages (except sometimes a tiny subapical spine), a highly three-dimensional telomere consisting of various lobes and lamellae with largely smooth margins.

Etymology

An anagram of Odontopyge . To be regarded as masculine in analogy with other names ending in –odon.

Other species included:

G. angolanus (Kraus, 1958) (comb. nov. ex Odontopyge )

G. bayoni (Silvestri, 1910) (comb. nov. ex Odontopyge )

G. carli ( Kraus, 1960) (comb. nov. ex Odontopyge )

G. dispersus (Carl, 1909) (comb. nov. ex Odontopyge )

G. erratus ( Kraus, 1960) (comb. nov. ex Odontopyge )

G. gracilitarsus (Kraus, 1958) (comb. nov. ex Odontopyge )

G. heteromodestus ( Kraus, 1960) (comb. nov. ex Odontopyge )

G. indecisus ( Pierrard, 1970) (comb. nov. ex Odontopyge )

G. intermedius (Carl, 1909) (comb. nov. ex Odontopyge )

G. iringensis gen. et sp. nov.

G. multianulatus ( Attems, 1914) (comb. nov. ex Odontopyge )

G. ollieri (Silvestri, 1907) (comb. nov. ex Odontopyge )

G. piceus ( Attems, 1938) (comb. nov. ex Odontopyge )

G. procerus ( Attems, 1914) (comb. nov. ex Odontopyge )

G. procerulus ( Kraus, 1960) (comb. nov. ex Odontopyge )

G. punctulatus ( Attems, 1912) (comb. nov. ex Odontopyge )

G. sennae ( Brölemann, 1903) (comb. nov. ex Odontopyge )

G. specularis ( Attems, 1927) (comb. nov. ex Odontopyge )

G. stenotarsus ( Attems, 1938) (comb. nov. ex Odontopyge )

G. submontanus gen. et sp. nov.

Descriptive notes

Species of Geotypodon gen. nov. have a typical odontopygid habitus ( Fig. 2 ) and are mostly mediumsized by odontopygid standards (cf. Kraus 1966). Published numbers of podous rings range from 49 ( G. ollieri ) to 72 ( G. multianulatus ) (one has been subtracted from the published numbers because these include the telson), and published male body diameters range from 1.7 mm ( G. sennae ) to 5.5 mm ( G. specularis ). The majority of species have 54–66 podous rings and a diameter of 4.3–5.5 mm, but there is a group of smaller species ( G. angolanus , G. erratus , G. heteromodestus , G. ollieri ) with 49–54 podous rings and a diameter of 2.2–3.2 mm. G. sennae is a particularly slender species: 66–68 podous rings and 1.7 mm diameter, and G. multianulatus , true to its name (at least as misspelled by Kraus (1960): multiannulatus), stands out with 72 podous rings and 4.8 mm diameter. Of the new species described here, G. millemanus gen. et sp. nov. falls neatly in the main group, G. submontanus gen. et sp. nov. is slightly more slender than the main group, whereas G. iringensis gen. et sp. nov. has a larger body diameter than any other described congener ( Fig. 3 ).

Several of the species assigned to Geotypodon gen. nov. have the same type of limbus (with handlike lobes) as the type species; this is true of G. angolanus , G. carli , G. erratus , G. gracilitarsus , G. procerulus and G. punctulatus ( Attems 1912; Kraus 1958, 1960) as well as G. submontanus gen. et sp. nov. Other species have other types of limbus: G. heteromodestus , G. indecisus , G. multianulatus , G. piceus , G. sennae , G. specularis and G. stenotarsus ( Attems 1914, 1927, 1938, 1953 [ G. heteromodestus , as Haplothysanus modestus ]; Brölemann 1903; Pierrard, 1970), as well as G. iringensis gen. et sp. nov. The limbus of procerus somewhat but not quite resembles that of G. millemanus gen. et sp. nov. ( Attems 1914), and no information is available about this character in G. bayoni , G. dispersus or G. intermedius . On the other hand, several species outside Geotypodon gen. nov. as here defined have the same type of limbus as G. millemanus gen. et sp. nov.. This is, for example, the case for several species of Rhamphidarpoides Kraus, 1960 , including R. kilimandjarona ( Attems, 1909) , R. ruandensis Kraus, 1960 , and R. regina (Carl, 1909) ( Attems 1914; Kraus 1960; Frederiksen & Enghoff 2015), Helicochetus spp. (e.g., Kraus 1966: figs 83–87), Solenozophyllum kazibaense Kraus, 1958 and ‘ Odontopyge ’ dewittei Kraus, 1958 .

Remarks

Although Geotypodon gen. nov. is proposed to accommodate several species of Odontopyge sensu Kraus (1960) , its diagnosis and circumscription are narrower. Species of Odontopyge sensu Kraus (1960) , may thus lack a long basad metaplical spine on the anterior side of the coxa (present in Geoptypodon), may have spines in the torsal region (absent in Geotypodon gen. nov.), and may lack a spine emerging from the base of the telomere and curving more or less parallel to the basal parts of the solenomere (present in Geotypodon gen. nov.).

None of the characters listed in the diagnosis are exclusive to Geotypodon gen. nov.: Notably, the conspicuous coxal metaplical anterior spine is also found in, e.g., several species of Rhamphidarpoides and Raduliverpa Frederiksen & Enghoff, 2015 ( Frederiksen & Enghoff 2015) as well as Spinotarsus Attems. nov. by

, 1909 ( Kraus 1960, 1966), but the species in question differ from Geotypodon gen either having the solenomere with spines or fluting ( Rhamphidarpoides , Raduliverpa ) or by having characteristic structures on the telomere (“Basallamelle” and/or “Bogenlamelle” sensu Kraus 1960) ( Spinotarsus ).

A spine emerging from the base of the telomere is also found in several other ’ Odontopyge’ species, e.g., citernii Silvestri, 1898 , difficilis Silvestri, 1895 , and severini, Silvestri, 1897 – see Kraus (1960), where this spine is called “Tibialdorn”. It is also found in Rhamphidarpoides species ( Frederiksen & Enghoff 2015), in Calyptomastix kakandae (Kraus, 1958) , as well as several Spinotarsus species, etc. In the Chaleponcus dabagaensis -group there is a spine at almost the same place, but emerging from the base of the solenomere instead of the base of the telomere ( Enghoff 2014).

Considering the notorious mosaic-like distribution of morphological characters throughout the family, the genus Geotypodon gen. nov. as defined here is quite possibly not a monophyletic group, cf. the Discussion section (see below). Until a more satisfactory analysis of relationships within Odontopygidae becomes available, the new genus can, however, serve as a ‘home’ for several (but not all) ‘orphaned’ species hitherto classified in Odontopyge .

Figures

Fig. 2. Geotypodon millemanus gen. et sp. nov., paratype from West Kilombero Scarp FR after nine years in alcohol. Photograph by N. Ioannou.

Fig. 3. Body size of males of Geotypodon spp. Bold symbols indicate numbers of podous rings and midbody vertical diameter of the new species described here. Small circles and shaded areas indicate