Rondostreptus kiellandi, Hoffman, Richard L., 2011

Hoffman, Richard L., 2011, Rondostreptus, a new spirostreptid genus from southeastern Tanzania (Diplopoda: Spirostreptidae), Zootaxa 2779, pp. 63-68 : 64-68

Rondostreptus kiellandi , new species

Figures 1 –13.

Material. Male holotype and female paratype ( VMNH): TANZANIA: Lindi District, Rondo Plateau, 800 m., in thick forest, April 1986, Jan Kielland. Male paratype ( VMNH): Rondo Plateau, 1987, Jan Kielland; five female paratypes ( VMNH): Rondo Forest Reserve, 10°08'S, 39°12'E, 60 km west of Lindi, 1993, Frontier Tanzania Group.

Name. For the collector, author of “The Butterflies of Tanzania ” and dedicated collaborator in surveying the Diplopoda of that country.

Diagnosis. With the characters of the genus.

Holotype. Adult male, broken into several curved and rigid fragments, but approximately 105 mm in length, body narrowest (8.3 mm) at segment 2, with maximum diameter (10.3 mm) at segment 40. 50 segments including collum and epiproct, only the latter legless. Coloration altered by preservation, but at present metazona largely reddish-brown with a slight purple cast dorsally, prozona more reddish-brown, becoming orange-brown at sterna; antennae and legs clear orange.

Head (Figs. 1,2) moderately convex, smooth, two prominent oval interantennal foveolae; interocular, epicranial, and occipital sutures distinct. Ocellaria large, IOI space distinctly less than IAI, ocelli in eight rows: 12-11-10- 8 -7-5-3-1=57, those of the upper and inner rows largest. Antennae long and slender, articles in decreasing size order: 2>3>4=5=6>7, basal antennomeres virtually glabrous; sensory pits of 5th and 6th of the size and shape shown in Fig. 2 .

Mandible ( Fig. 3 ) with three large and one small dentations on the psectromere; about 15 rows of pectinate lamellae, many of which are incomplete and/or concealed. Basal article convex laterally, distally produced into a prominent lobe that overlaps on gnathochilarial stipe. Gnathochilarium ( Fig. 4 ) of typical spirostreptid form, but prebasal sclerite reduced to a small quadrate remnant subtending each stipe, the membrane between them lightly sclerotized.

FIGURES 5–7. Rondostreptus kiellandi . Peripheral structures. 5. Lateral lobe of collum, left side. 6. Leg of midbody segment, setation shown accurately. 7. Right side of 1st pair of legs, anterior aspect, showing separated coxae and reduced prefemoral processes. Drawings from holotype, not all to same scale.

Collum (Fig. 5) produced cephaloventrad as a rounded lobe; lateral surface with two long complete ridges and several shorter interspersed. Metazona of body segments (rings) slightly elevated above level of prozona and ornamented dorsally with prominent broad, shallow depressions of varying shape but typically triangular, narrowest at stricture, extending nearly to caudal edge, surface of these depressions finely microgranulate and contrasting with the smooth and polished surface of the interspaces, typically about eight between the ozopores. Latter small, located on a flat smooth interspace, below which are about 27–28 prominent ridges becoming closer-set and cariniform in approaching sterna, the three ventralmost strongly oblique. Sterna smooth or with at most a single transverse striation near anterior edge. Stigmata small, contained entirely within sterna. Posterior coxal cavities not closed by ends of pleuroterga. Prozona with about eight fine concentric striations, closest spaced anteriad. Sigilla in a broad band of small round dots of variable size, disposed in about 4–5 irregular rows.

FIGURES 8–12. Rondostreptus kiellandi . Gonopod structure. 8. Right gonopod, anterior aspect. 9. Right gonopod, lateral aspect showing musculature of coxosternal sclerites (TS1 and TS 2, tracheosternal and TC, tracheocoxal muscles). 10. Right gonopod, oblique anterolateral aspect. 11. Torsotope region of telopodite, showing relationship of torsus to the antetorsal process (stippled). 12. Apex of telopodite. Drawings from holotype, not all to same scale.

Epiproct without modification, middorsally not produced over paraprocts. Latter moderately convex, margins not notably thickened, submarginal groove very shallow and poorly defined.. Hypoproct transversely triangular, surface of its posterior third flattened and conspicuously coarsely punctate-rugulose.

Legs (Fig. 6) long (ca 7 mm at midbody), tibiae and tarsi visible from above when extended. Tibiae and tarsi of all legs with membranous ventral pads, extending entire length of podomere over most of body but gradually reduced to small rudiments on last several pairs of legs.

First pair of legs (Fig. 7) of typical spirostreptid form, coxae separated, prefemora not extended laterad, their processes small, subtriangular.

Gonopods (Figs. 8–12) with prominent sclerotized lambdoid mesosternum, its lateral ends overlapping the ectosterna; coxa laterally broad, posteriorly narrowed and arched over ectosternum (Fig. 10), contiguous on inner side of metaplica with mesosternum. Proplica slender, its distal third acuminate and directed mesad, the edge with 4–6 acute subapical dentations and a more proximal field of short setae. Metaplica proximally slender, distally expanded and forming a distal rounded lobe and lateral truncate lobe. Telopodite slender at arculus, broadened toward region of torsion where rotated 360°, thence reflexed as a flattened blade to emerge behind the metaplica beneath its lateral lobe; apex abruptly constricted and provided with a tongue-shaped thin lobe (Fig. 12). Antetorsal process about twice width of telopodite, curved laterad, distally acuminate into a long acute point.

Female paratype. Body with 53 segments, maximum diameter 12.0 mm. Generally similar to male but color better preserved, metazona piceous, prozona light reddish-brown. Collum not lobed anteroventrally, with three complete lateral ridges. Metazonal ornamentation as fully expressed as in the males.

Variation. The male paratype, with 52 segments, is slightly narrower than the holotype with a diameter of 9.5 mm. Of the six female paratypes, the segment counts are 53, 53, 53, 53, 55, and 56, the maximum diameters respectively are 9.5, 11.5, 12.0, 12.0, 12.1, and 12.2 mm. The smallest specimen appears to be mature, with 53 segments.

Figures

FIGURES 1 – 4. Rondostreptus kiellandi. Head and mouthparts. 1. Head, left antenna removed, oblique anterolateral aspect. 2. Head, anterior aspect. Size and shape of the sensory pits of antennomeres 5 and 6 are shown in outline in their respective locations. 3. Mandible. 4. Left side of gnathochilarium and mandibular basomere, posterior aspect. Drawings from holotype, not all to same scale.