Opisotretus hagen, Golovatch, Sergei I., Geoffroy, Jean-Jacques, Stoev, Pavel & Spiegel, Didier Vanden, 2013

Golovatch, Sergei I., Geoffroy, Jean-Jacques, Stoev, Pavel & Spiegel, Didier Vanden, 2013, Review of the millipede family Opisotretidae (Diplopoda, Polydesmida), with descriptions of new species, ZooKeys 302, pp. 13-77 : 40-41

publication ID

https://dx.doi.org/10.3897/zookeys.302.5357

persistent identifier

https://treatment.plazi.org/id/A9239820-B4BD-8CF2-486F-1913007163E6

treatment provided by

ZooKeys by Pensoft

scientific name

Opisotretus hagen
status

sp. n.

Opisotretus hagen   ZBK sp. n. Figs 22, 23

Type material.

Holotype ♂ (NMNHS), Papua New Guinea, Western Highlands Prov., Mount Hagen, ca 1990 m a.s.l., in town, 22.10.1975, leg. P. Beron (British Speleological Expedition).

Paratypes.

1 ♀ subadult (19 segments), 1 juv. (fragments) (NMNHS), 1 ♀ subadult (19 segments) (SEM; MNHN JC 340), same locality, together with holotype.

Diagnosis.

Differs readily fromcongeners by a modified ♂ head (two prominent paramedian tubercles above the antennal sockets), coupled with a less strongly curved, nearly suberect gonopod telopodite, with its apical piece crowned with several peculiar, mostly digitiform outgrowths.

Name.

Referring to the type locality; a noun in apposition.

Description.

Length of holotype (and of subadult ♀ paratypes) ca 9 mm, width of midbody pro- and metazona 0.8 and 1.15 mm, respectively. Coloration in alcohol from uniformly pallid to light yellowish.

Body with 19 (♂) or 20 (♀) segments. All characters like in Retrodesmus cavernicola sp. n., except as follows.

♂ head with two round, paramedian, rather high tubercles (t) above antennal sockets (Fig. 23A). Antennae medium-sized, strongly clavate, extending behind segment 2 when stretched dorsally (Figs 22D, 23A).

In width, collum << segment 2 <head = 3 <4 <5 (6) =15 (♂), thereafter body gradually tapering towards telson. Paraterga rather strongly developed, starting from collum, mostly subhorizontal to slightly declivous, set high, but always lying slightly below a moderately (♀, juv.) to weakly (♂) convex dorsum, with rather faint shoulders frontolaterally (Figs 22 A–C). Caudal corner of postcollum paraterga dentiform, always pointed and extending increasingly well behind rear tergal margin. Lateral edge of paraterga with 2 or 3 small setigerous indentations in poreless and poriferous segments, respectively. Ozopores evident, round, flush open on dorsal surface, located very close to caudal margin at bottom of caudalmost lateral incision (Figs 22C, E, M), lateral tooth being very considerably shorter than medial one. Collum and each following metatergum with 3+3 long bacilliform setae arranged in three regular transverse rows; polygonal bosses flat, but visible (Figs 22 A–F).

Sterna without modifications, rather broad, strongly setose (Fig. 22H). Legs long, incrassate in ♂ due to prefemora alone (Figs 22N, 23B), ca 1.5 times (♂) as long as midbody height; femora and tarsi longest, subequal in length; sphaerotrichomes or other modified setae missing.

Gonopod telopodite (Figs 23C, D) only very slightly curved, nearly suberect, unipartite, rather long and slender; apical piece (a) distal to a very short solenomere (sl) rather short, on caudal face with a few finger-shaped ornamentations and a strong, parabasal, subspiniform process (pr). An accessory seminal chamber at base of sl evident, crowned with a hairy pulvillus.

Remarks.

This is the first Opisotretus showing ♂ head modifications, thus confirming the character as being only species-specific ( Golovatch 1988).