Dorypetalum helenae, Stoev, Pavel & Enghoff, Henrik, 2006

Stoev, Pavel & Enghoff, Henrik, 2006, A review of the millipede genus Dorypetalum Verhoeff, 1900 (Diplopoda: Callipodida: Dorypetalidae), Zootaxa 1254, pp. 29-43 : 31-34

Dorypetalum helenae sp. n.

Figs 2–14

Material examined

Holotype: adult male; Turkey (European part), Edirne Province, Kuru Daġ Mts, SE Keşan, 350 m, Pinus / Quercus forest, 9.v.1995, H. Enghoff, M. Frater, H. Read leg. (Zool. Mus. Copenh. Exp.) (Natural History Museum of Denmark — ZMUC) — Paratypes: 2 females, 1 juvenile, same locality, date and collectors as holotype ( ZMUC).

Etymology

The species is named after the British myriapodologist Dr. Helen Read, a participant in the expedition to Turkey organized by the ZMUC, very likely the actual collector of the new species and author of several papers on millipede taxonomy.

Description

Length: adult male broken, exact length unknown, adult female: ca. 17 mm. Width of midbody pleurotergite (PT) of female paratype: 1.2 mm. Adults with 43 PTs; juvenile with 35 PTs.

Body color (Fig. 2): generally brown­gray­yellowish; metazonites with dark, brownish, posterior band; prozonites grey­whitish; dorsal crests usually darker, contrasting against a yellowish background; collum and next five PTs with medial dark band, forming something like an uninterrupted darker line extending from middle of collum to posterior end of PT6 (Fig. 4); legs pale brown­yellowish; antennae (excluding apical cones) and head dark brown. Front of head concave in males, convex in females, covered with slender, whitish setae: frontal margin brownish, sometimes with irregular lighter spots in the middle, labral zone yellowish, edge between the frontal and posterior side of head, stipes and cardo marbled yellowish — brown (Fig. 3). Ocellaria subtriangular, composed of 22 transparent ocelli arranged in 5 rows on a black background. Organs of Tömösváry larger than an ocellus, placed between anterior side of ocellar triangle and antennal pit, well separated from both. Antennae: moderately long, almost reaching the mid of PT 6 when folded backward; fifth antennomere with a posterior field of stout sensilla (Fig. 5); eight article comprised of 4 short, whitish cones. Male sixth and seventh PTs moderately enlarged, not as strongly as in some other callipodidans (e.g. Paracortina , Bollmania ).

Collum smooth, other anterior PTs with moderately developed almost flattened crests, crests getting more pronounced towards the body end. Four crests between the ozopores on seventh PT. Ozopores visible on all PTs from the 6th backwards, except on the last two PTs, placed at the base of 3rd crest. Chaetotaxy: Table 1.

First and second leg­pairs markedly shorter, third slightly shorter than subsequent legs, all with tarsal claws, tarsi undivided, ventrally with a row of long setae instead of pads (Figs 6–8). Male leg­pairs 4–7 without tarsal claws, tarsi with a trace of division; pads poorly developed, concentrated on the posterior third (7 l. p.) or fourth (4– 6 l.p.) of tarsi.

Prefemur of first male leg with a lateral outgrowth (j) on its posterior side (Fig. 6). Coxae of second leg pair with posterior gonopore (Fig. 7). Male third leg unmodified (Fig. 8). Prefemur of male 4th leg heavily enlarged, with ventral outgrowth (h), coxa projected ventrally, its apical part pointed and curved cephalad (Fig. 9). Prefemur of male 5th leg­pair moderately enlarged, subconcave ventrally (Fig. 10). Coxa of male 6th leg dorsally expanded, femur incrassate (Fig. 11). Coxa of male 7th leg with a long ventral protrusion (z), prefemur with a posterior thickening, femur slightly incrassate, tarsus elongated (Fig. 12). Coxal sacs present at least from 3rd to 7th leg pair, in subsequent legs either missing or not visible. Hypoproct tripartite, medial sclerite largest, trapezoidal, bearing two paramedian macrosetae. Paraprocts divided into larger ventral and smaller dorsal sclerites, each bearing a pair of macrosetae. Spinnerets thin and long, ending with a long macroseta.

Anterior setae Posterior setae

Collum a, d + a, d b, c, e + b, c, e

2nd pleurotergite a, d, e a + a, d, e b, c + b, c

3rd pleurotergite a, e + a, e b, c, d + b, c, d

4th pleurotergite a + a b, c, d, e + b, c, d, e

5th pleurotergite a + a b, c, d, e + b, c, d, e

6th pleurotergite ­ a, b, c, d, e + a, b, c, d, e

7th pleurotergite a + a b, c, d, e, f + b, c, d, e, f

8th pleurotergite a + a b, c, d, e, f + b, c, d, e, f

a. Setae d and e are not in a truly anterior position, just about the mid distance between the anterior and posterior rows. The same holds true for seta e on the third PT.

Male gonopods (Figs 13–14): telopodite (t) and prefemoral process (pf) as typical for the genus (see Hoffman & Lohmander (1964) for detailed description). Mesal coxal process (mp) long, erected, apically broadened, racket­shaped, its apical part subdivided into a dorsal (d) and a ventral (v) lamina, t and pf ending close to them; tuft of long and stout setae (k) placed in a row at about midlength of the anterior side of mp; upper edge of larger lamina somewhat irregularly serrate, bearing a few tiny setae. Lateral coxal process (lp) S ­shaped, apically pointed, as high as 2/3rd of the mesal coxal process, a small distal tooth (f) placed at about its midlength. The new species differs significantly from the other congeners in the shape of the mesal coxal process.

Females: Second leg pair normal. All female legs with a tarsal claw.

Remarks

Regarding the shape of gonopods, D. helenae sp.n. is morphologically close to D.

bulgaricum Strasser, 1973 , both species being characterized by the cluster of spines lying directly on the anterior side of the mesal coxosternal process (see also the key below). However, it is well distinguished from the latter by the specific racket­shape of the mesal process, and also by having the lateral process apically pointed, devoid of denticles. D. bulgaricum is unique among all congeners in having an extra pleurotergite, i.e. 44 vs. 43, but the significance of this character for species characterisation in Dorypetalidae is still uncertain.

PLATE 1. Dorypetalum helenae sp. n., female paratype: Fig. 2: lateral view; Fig. 3: ventral view; Fig. 4: dorsal view.

Being quite uniform with regard to the telopodite and prefemoral processes, the question whether the mesal and lateral processes of dorypetalid gonopods are of any importance to species distinction or their slightly different shape is due to an individual variation was brought up by Hoffman & Lohmander (1964). This issue was commented also by Strasser (1974) who stated “.... the question remains open whether we are dealing with different species or, as Hoffman suspects, with a single, geographically strongly variable species“ (our translation). We think that the new evidence at hand, and especially the quite unusual shape of the mesal process in D. helenae , show that these characters are of certain value and can be used for taxonomic purposes. Other taxonomically important characters for species’ separation can be observed in male pregonopodal legs.

PLATE 2. Dorypetalum helenae sp. n., holotype: Fig. 5: antenna, lateral view; Figs 6–12: male legs 1–7, respectively, anterior views. Abbreviations, see text. Scale bar: 1 mm.