Sphaerotherium dorsale (Gervais, 1847)

Spiegel, Didier Van den, Golovatch, Sergei I. & Hamer, and Michelle L., 2002, Revision of some of the oldest species in the millipede genus Sphaerotherium Brandt, 1833 (Diplopoda, Sphaerotheriida, Sphaerotheriidae), with new synonymies, African Invertebrates 43, pp. 143-181 : 154-156

Sphaerotherium dorsale (Gervais, 1847)

( Figs 26a–h , 35 )

Sphaerotherium retusum C. L. Koch, 1847 . Synonymy confirmed.

Material studied:

Type material: S. dorsale : ^ holotype; provenance unknown; MHNP .

S. retusum : Ò holotype; South Africa, Cape of Good Hope ; ZMB 64 .

Other material: 2^, types (?), South Africa, Caffraria; 1840–1845; J. A. Wahlberg; SMNH .

Numerous Ò and ^ from MRAC, SAMC and TMSA, various dates and collectors.

Description:

Total length ranging from 10–35, width from 7–15, average length 25.

Colour: Head, antennae and collum dark olive green. Thoracic shield, tergites and pygidium castaneous, a little darker along posterior margin. Underside and legs dark olive green.

Head densely punctate-pilose, with hairs growing denser toward clypeus; gnathochilarium densely pilose, labrum with a single median tooth. Ocelli obvious, almost black. Antennae with numerous apical sensory cones (up to 38).

Collum densely punctate-pilose, with one row of long hairs along margin.

Thoracic shield setiferous; brim large, accompanied by a row of longer setae.

Tergites 2–12 with well-developed black keels, surface covered with very dense setiferous punctures providing the impression of a furry body ( Fig. 26b ). Endotergum with one row of scaled marginal bristles extending up to margin, marginal ridge with a row of very small callosities. A row of cuticular patterns forming a row of light spots behind ridge. Intersegmental membrane densely covered with long hairs, dark cones only visible in median part ( Figs 26g , 35 ).

Legs without lateral lobe on coxa ( Fig. 26c ).

Male sexual characters:

Second pair of legs bearing pseudopenes, latter rather narrow and short ( Fig. 26d ); no coxal lobe.

Pygidium depressed in the middle, with an elevated margin ( Fig. 14 ).

Anterior telopods with an incompletely divided or undivided tarsus, distal outer surface of anterior part beset with a series of sclerotised ridges, apical anterior bearing a small wart and a small tactile spine ( Fig. 26i ). Posterior telopods with pincers relatively flat, less strongly arched than in other species. Lateral side of median tibial process with one triangular protuberance. Tarsus 1-segmented, a row of striated knobs on anterior side, concavity with some spines on a low protuberance and a slightly enlarged apical part ( Fig. 26e, f ).

Female sexual characters:

Second pair of legs without coxal lobe. Cyphopod with a rounded operculum.

Comments: Attems (1928) considered S. retusum as a synonym of S. dorsale . Although his opinion was obviously not justified by a restudy of pertinent type material, we agree as the holotypes of the two species share the same body and posterior telopod structure, which alone is sufficient for safely determining the species.

The synonymy of Zephronia puverea with Sphaerotherium dorsale proposed by Schubart (1958) requires verification as this was not explained by him and was apparently not based on a restudy of pertinent types.

As the paper by Gervais (1847) appears to have been published a few months earlier than C. L. Koch’s (1847) (cf. Jeekel, 1970), the name S. dorsale has priority over S. retusum .

As Sphaerotherium retusum C. L. Koch, 1847 is the type species of both Bournellum De Saussure & Zehntner, 1902 , and Eubournellum Attems, 1908 , the latter name is a junior objective synonym to be suppressed ( Jeekel 1970). Bournellum is currently the earliest available genus-group name to encompass the congeners with seven or more sensory cones on the ultimate antennomere (see also below under S. rotundatum ). However, this character is so weak that we cannot uphold this subgeneric division of Sphaerotherium . There is one large sample of a Sphaerotherium species from KwaZulu-Natal (NMSA) containing a single specimen with six cones on antennomere 8, meaning that any classification based on this character alone cannot be used.

Figures

Figs 26a–i. Holotypes of Sphaerotherium retusum (a–h) and Sphaerotherium dorsale (i). a: apical part of antenna; b: lateral aspect of Ò; c: leg 9; d: penes; e: posterior view of apical part of telopod; f: anterior aspect of apical part of telopod; g: endotergum; h: posterior view of anterior telopod; i: cyphopod.

Figs 34–42. Endotergum (SEM) in Sphaerotherium species. 34. S. compressum (^paralectotype). 35. S. dorsale (^ holotype). 36. S. elongatum (^ paralectotype). 37. S. giganteum (^ lectotype). 38. S. intermedium (^ holotype). 39. S. lichtensteinii (^ paralectotype). 40. S. obtusum (^ holotype). 41. S. punctatum (^ lectotype). 42. S. punctulatum (Ò lectotype).

Figs 14–24. Sexual characters in Sphaerotherium. 14. S. trichopygum Ò, posterolateral view of pygidium. 15. S. retusum Ò, lateral aspect of pygidium. 16–17. Cyphopods. 16. S. elongatum. 17. S. intermedium. 18. S. trichopygum Ò, main stridulatory organ (t: posterior telopodite, arrow: patch of granules on underside of pygidium). 19–20.Anterior telopod. 19.Anterior aspect. 20. Posterior aspect. 21. Posterior view of stridulatory organ of posterior telopod. 22.Anterior aspect of posterior telopod.23. Structures in apical part of anterior telopod, posterior view. 24.Apical part of posterior telopod showing a finger-shaped process (arrow).