Syndesmogenus voiensis ( Ribaut, 1907 )

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 : 95-98

Syndesmogenus voiensis ( Ribaut, 1907)

Figs 58–59

Odontopyge voiensis Ribaut, 1907: 511

Spinotarsus voiensis – Attems 1909a: 51.

Syndesmogenus voiensis – Kraus 1960: 181.

? Syndesmogenus sp. (probably n.sp.) – Enghoff & Enghoff 1976: 7.

Material examined (total 2 ♂♂)

TANZANIA • 1 ♂; East Usambara Mts, Amani, Kwamkoro ; ca 1000 m a.s.l.; 24 Dec. 1975; O. Lomholdt leg.; in rotten wood; NHMD 621763 . – not Eastern Arc • 1 ♂; Kilimanjaro Region, Mt. Kilimanjaro, coffee plantation ; 37.32028° E, 3.247895° S; 1305 m a.s.l.; 2013; S. Frederiksen leg.; NHMD 621764 .

Description (male from Amani)

SIZE. Length 42 mm, diameter 1.5 mm, 74 podous rings, no apodous rings in front of telson.

COLOUR. After 37 years in alcohol overall yellowish, but with large brown areas at ozopore level (not defense glands shining through) resulting in a dorsal light band, dorsolateral dark bands and ligt ventral half. Legs yellowish.

SUPRALABRAL SETAE. Not recognisable.

MANDIBULAR STIPES. Subrectangular, ventral margin shallowly bilobed/concave.

BODY RINGS. Metazonites vaulted, rendering the body somewhat moniliform. Cuticle, at least in front of limbus, with numerous interscutal bands carrying a row of very small (ca 0.001 mm) beadlike structures (fungi?) which seem to have fallen off in some cases ( Fig. 58D ). See Enghoff & Reboleira (2017).

ANAL VALVES. Without spines or protruding corners, posterior margin raized, each with three setae on poorly developed ravelins.

LIMBUS ( Fig. 58C ). Margin with short, blunt-angled yet pointed lobes, smooth except for one ridge running into each lobe.

LEGS. With postfemoral and tibial pads, covering whole length of podomeres, from leg-pair ca 6, diminishing and eventually disappearing toward hind end.

FIRST PAIR OF LEGS ( Fig. 58E–G ). Prefemoral lobes rounded-triangular in ventral view. One to two coxosternal setae (CXS) close to lateral margin of coxosternum, well separated from prefemoral lobes. Prefemora with two mesapical setae (APS) and a few lateral setae (LPS).

STERNUM 9. Lost during dissection. In a specimen from Mt. Kilimanjaro, the posterior sternum is longer than broad, subrectangular with concave lateral and basal margins and a slightly convex apical margin ( Fig. 58H )

GONOPOD COXA ( Fig. 58A–B ). Slender, straight, cucullus (CU) with a large, blunt-triangular process (mcp). Proplica (PP) simple, proplical lobe hidden behind fold of metaplica. Metaplica (MP) with a poorly delimited mesad flange (MF) basally, distally flexed back on anterior side and forming broad, triangular, pointed spinelike process (msp) covering distal part of proplica.

GONOPOD TELOPODITE ( Figs 58A–B , 59 ). Arculus 90°. Torsotope (TT) relatively extended, a long posttorsal spine (PTS) making a full turn around post-torsal narrowing and projecting basad (dorsad), posttorsal narrowing hence not visible. Solenomere (SLM) separating from telomere immediately after posttorsal narrowing, very long, much longer than telomere, slender, simple; a long, very thin spine (BSS1) branching off from base of solenomere, a shorter but stouter spine (BSS2) branches off SLM a little after. A tiny spinelike side branch (slb) in the distal part of SLM, but still quite far from solenomere tip ( Fig. 59D–E ). Telomere (TM) much longer than broad, extremely complicated, overall apparently consisting of a broad, twisted lamella with various fold and secondary lamellae, including a longtriangular structure also described by Ribaut (1907) who labelled it “d”.

Distribution

Previous Eastern Arc records: None.

General distribution: described from Voi in southern Kenya ( Ribaut 1907), subsequently reported from Tanga in North-East Tanzania by Brolemann (1920) and from Tanzania: Mt. Kilimanjaro by Enghoff & Frederiksen (2018). In the Eastern Arc mountains known only from Kwamkoro in Amani Nature Reserve, E Usambara Mts, altitude 1000 m a.s.l. See Doody et al. (2001) for information on this area.

Remarks

A careful comparison of the East Usambara specimen with the detailed original description ( Ribaut 1907) reveals numerous points of agreement, but also some differences. Thus, the telopodital spine called e1 by Ribaut corresponds to the post-torsal spine (PTS) in the East Usambara specimen, and likewise e2 (= BSS1) and e3 (= BSS2). Spine PTS in the East Usambara specimen is, however, much longer than Ribaut’s e1, whereas spine BSS2 is shorter than his e3. The tiny solenomeral side branch (slb) was not mentioned, nor illustrated by Ribaut (1907). In the key of Kraus (1960) this branch would lead to S. spiralis (Carl, 1909) . However, slb is very small and inconspicuous and may well have been overlooked by Ribaut (it was actually initially not recognized on the East Usambara specimen, but the presence of a similar spine in S. estelleae sp. nov. inspired successful re-scrutiny), and apart from this discrepancy, the East Usambara specimen runs easily to S. voiensis in the key. The triangular coxal lobe called a by Ribaut seems not to be present in the East Usambara specimen. The telomeral lobe d of Ribaut can also be identified in the East Usambara specimen, and the construction of the telomere which Ribaut characterized as “Les lamelles présentent une forme extrêmement compliquée” in general seems to be similar. Comparison with a male from Mt. Kilimanjaro identified by Sara Frederiksen ( Enghoff & Frederiksen 2018) revealed partly different minute differences, and S. voiensis as understood here may indeed prove to include several species.

Figures

Fig. 58. Syndesmogenus voiensis (Ribaut, 1907). A–G. Specimen from E Usambara Mts (NHMD 621763). A. Right gonopod, anterior view. B. Right gonopod, posterior view. C. Midbody dorsal limbus, notice interscutal structures. D. Interscutal structures (fungi?) with spherical bodies to the left in the picture and?sockets after such structures to the right. E–G. First pair of legs. E. Ventral view. F. Sublateral view. G. Anterior view. H. Specimen from Mt. Kilimanjaro (NHMD 621764), sternum 9. Abbreviations: APS= mesapical prefemoral setae;BSS1, BSS2= basal solenomeral spines;CU = cucullus; CXS = coxosternal setae; LPS =lateral prefemoral setae; mcp =mesal cucullar process; MP=metaplica; msp = metaplical spinelike process; PP =proplica; PTS =post-torsal spine; SLM = solenomere. Scale bars: A–B, E–F =0.1 mm; C=0.01 mm; D =0.001 mm; G–H=0.05 mm.

Fig. 59. Syndesmogenus voiensis (Ribaut, 1907), specimen from E Usambara Mts (NHMD 621763), right gonopod. A. Mesal view. B. Subdistal (subventral) view. C. Distomesal view. D. Tips of solenomere and telomere. E. Close-up of solenomeral side branch. Abbreviations: BSS1, BSS2 =basal solenomeral spines; CU =cucullus; “d” =structure “d” sensu Ribaut (1907); mcp =mesal cucullar process; MP=metaplica; PP =proplica; slb =solenomeral side branch; SLM =solenomere. Scale bars: A–C=0.1 mm; D =0.05 mm; E =0.01 mm.