Spinotarsus axeli, Enghoff, 2022

Enghoff, Henrik, 2022, Mountains of millipedes. The family Odontopygidae in the Eastern Arc Mountains of Tanzania (Diplopoda, Spirostreptida), European Journal of Taxonomy 803, pp. 1-136 : 88-91

Spinotarsus axeli sp. nov.

urn:lsid:zoobank.org:act:9B6978B5-2771-4984-AE66-A93A2C07E764

Figs 3A , 4A , 54–55

Diagnosis

Differs from other species of Spinotarsus by the huge, slightly curved spine (LCS) which is directed latero-basad.

Etymology

After Axel Kristen Enghoff (1924–2014), the author’s father and ‘landlord’ of ‘Hotel Dolichoiulus’.

Material examined (total 3 ♂♂)

Holotype TANZANIA • ♂; Shikurufumi FR ; 37°31′ E, 7°09′ E; Sep. 2000; Uluguru Mountains Biodiversity Conservation Project, Nike Doggart leg.; submontane forest; NHMD 621761 .

Paratypes TANZANIA • 2 ♂♂; same collection data as for holotype; NHMD 621762 .

Description (male)

SIZE. Length 68–70 mm, diameter 4.6–5.1 mm, 57–59 podous rings, no apodous rings in front of telson.

COLOUR. After 18 years in alcohol all whitish.

SUPRALABRAL SETAE. 6–7.

MANDIBULAR STIPES. Shallowly concave.

ANAL VALVES. With large dorsal spine and distinct ventral ‘corner’; margins barely raised, three sessile setae on each.

LIMBUS ( Fig. 54D ). Margin with slender pointed-triangular lobes, ca twice as long as broad.

LEGS. Postfemoral and tibial pads present from leg-pair 6 backward, diminishing and eventually disappearing.

FIRST PAIR OF LEGS ( Fig. 54E–G ). Prefemoral lobes broadly rounded-triangular in ventral view. A single coxosternal seta (CXS) close to lateral margin of coxosternum, well separated from prefemoral lobes. Prefemoral setae/sensilla indistinct.

STERNUM 9 ( Fig. 54H ). Triangular.

GONOPOD COXA ( Fig. 54A–C ). With a huge latero-basad, slightly curved spine (LCS). Proplical lobe (PPL) not covered. Metaplica with a large metaplical flange (MF) and more distally, a semi-circular lobe (ml).

GONOPOD TELOPODITE ( Fig. 55 ). Arculus 90°. Torsotope compact, almost completely hidden by 1½ coil of very long post-torsal spine (PTS). Post-torsal narrowing (PN) very pronounced. Solenomere (SLM) long, ca same length as telomere, simple, whiplike, coiling irregularly, without outgrowths, with a long straight spine (BSS) at base. Telomere (TM) with a rounded-rectangular, inconspicuously spinose basal lamella (bla), its distal part a broad, longitudinally folded sheet bent into U-shape, narrowing towards tip, one margin near tip with coarse denticles ( Fig. 55A , inset)

Distribution and habitat

Known only from the Shikurufumi FR in the Uluguru Mts, cf. Doggart et al. (2004).

Remarks

The basal lamella (bla) which is very inconspicuously spinose (spinules not visible on Fig. 55B ) suggests placement in the large genus Spinotarsus , and no other characters are in conflict with this allocation. Like the only other species of Spinotarsus known from the Eastern Arc Mts, S. fortehamatus Enghoff, 2018 , the new species lacks a darkly sclerotized ridge on the posterior surface of the telomere, a character found in very many congeners. In the key to Spinotarsus species by Kraus (1966), S. axeli sp. nov. runs without problems to couplet 60, as follows. Couplet 1: Gonopodal metaplica with one or several dark sclerotized lateral spines which stand clearly out in strict oral view → couplet 38: One or more spine(s) (“Postfemoraldorn”) at base of solenomere present → couplet 59: One spine at base of solenomere → couplet 60. Couplet 60 (cf. Enghoff 2018) leads to couplet 65 where the choice is between the lateral metaplical spine being directed more or less apicad, or being horizontal (strictly laterad); however, in S. axeli sp. nov. the lateral spine is directed obliquely laterobasad which seems to be unique in the genus.

Figures

Fig. 3. Heads of odontopygid males, arrows point to distal margin of mandibular stipes. A. Spinotarsus axelisp. nov.,holotype(NHMD621761),distalmarginof stipesconcave/bilobed,as inmostodontopygids. B. Callistodontopyge latifolia (Attems, 1914), specimen from Kiverenge FR (NHMD 621713), distal margin of stipes trilobed as characteristic of this genus. Scale bars=1 mm. Photo S.G. Selvantharan.

Fig. 4. Telsons of odontopygids. A. Spinotarsus axeli sp. nov., holotype, ♂ (NHMD 621761), telson and last six body rings, lateral view. B. Xystopyge bentemarieae sp. nov., paratype, ♂ (NHMD 621767), telson, lateral view, showing two setae per anal valve as characteristic of the genus Xystopyge. C–D. Aquattuor udzungwensis Enghoff, 2015, telson and last body ring (from Enghoff & Frederiksen 2015), showing three setae per anal valve as characteristic of most odontopygids; setae in this species placed on ravelins on raised valve margins. C. Lateral view, also showing the rectangular limbus flaps characteristic of the genus Aquattuor. D. Posterior view. Stars indicate the dorsal anal valve spines characteristic of family Odontopygidae; white arrows indicate anal valve setae. Scale bars: A=1 mm; B–D=0.1 mm. A–B: Photo S.G. Selvantharan.

Fig. 54. Spinotarsus axeli sp. nov., holotype, ♂ (NHMD 621761). A–C. Left gonopod coxa. A. Anterior (-mesal) view. B. Posterior view. C. Mesal view. D. Midbody dorsal limbus. E–G. First pair of legs. E. Anterior view. F. Ventral view. G. Sublateral view. H. Sternum 9. Abbreviations: CXS=coxosternal seta; LCS= lateral coxal spine;MF =metaplical flange; ml =metaplical lobe;PPL =proplical lobe. Scale bars: A–C, E–F = 0.2 mm; G–H= 0.1 mm; D =0.01 mm.

Fig. 55. Spinotarsus axeli sp. nov., holotype, ♂ (NHMD 621761), left gonopod telopodite. A. Anterior view, inset: tip of telomere. B.Posterior view. C. Venral view. D. Dorsal view. E. Anterior-dorso-apical view. F. Posterior-dorsal view. Abbreviations: bla= basal telomeral lamella; BSS =basal solenomeral spine; PN= post-torsal narrowing; PTS =post-torsal spine; SLM =solenomere; TM =telomere. Scale bars =0.2 mm.