Ommatoiulus xenos Akkari & Enghoff

Akkari, Nesrine, Cheung, David Koon-Bong, Enghoff, Henrik & Stoev, Pavel, 2013, Revolving SEM images visualising 3 D taxonomic characters: application to six species of the millipede genus Ommatoiulus Latzel, 1884, with description of seven new species and an interactive key to the Tunisian members of the genus (Diplopoda, Julida, Julidae), ZooKeys 328, pp. 5-45 : 17-18

Ommatoiulus xenos Akkari & Enghoff sp. n. Figs 27-30

Material.

Holotype: ♂, Tunisia ( “Tunis”), 1861, J.P. Coindé leg. (MNHN). Paratypes: 5 ♀♀, Tunisia ( “Tunis”), 1861, J.P. Coindé leg. (MNHN).

Diagnosis.

Resembling Ommatoiulus chambiensis and Ommatoiulus xerophilus spp. n. in size and general shape of gonopods, but distinguished by the shape of promerite, a much more slender mesomerite and shorter and stouter paracoxite.

Etymology.

The species name is a Greek noun meaning ‘stranger’, emphasising the fact that this species, found surprisingly in the collection of the MNHN shortly before completion of the manuscript, had remained unknown and out of the sight of a number of myriapodologists for more than 150 years.

Description.

Male: L: 20.5 mm, H: 1.85 mm, 47 PR+2 AR+T; females: L: 18.5-21 mm, H: 2.26-2.46 mm, 42-48 PR+2-3 AR+T. General colour faded, generally grey-greenish (very likely an artefact from the decomposition of the inserted label), somewhat lighter laterally. Head pale in the occipital and labral areas; antennae and legs darker. Prozonites with darker triangular spots laterally, latter situated along the ozopores line and forming two longitudinal dark bands, dorsally separated by a pale one; dorsum crossed by dark triangular spots and showing a thin black mid-dorsal line; metazonites mostly pale and glossy. Telson: anal valves and preanal ring dark, subanal scale pale.

Prozonites with fine striae; metazonites with regular striae, denser on the sides, suture complete, curving at the level of ozopores; ozopores small, rounded, situated on metazonites situated at about their diameter from the suture. Anal valves setose; preanal ring with 3-4 setae on each lateral side, protruding in a short caudal projection with 1-4/5 setae and a small hyaline process on the tip. Subanal scale blunt to rounded and setose.

Male sexual characters. Mandibular stipites expanded in rounded posterior-ventral lobes, first pair of legs hook-shaped, remaining legs with postfemoral and tibial pads.

Gonopods. Promerite (Fig. 27) gradually narrowed distally, lateral margin with a shallow incision (i); apical process of promerite with a rounded margin pointing laterad; mesal ridge (M) narrow, distally protruding in a pointed apex (mp) separated from the apical process by a small apical incision; remnant of telopodite not very conspicuous.

Posterior gonopod (Figs 28-30): Mesomerite (Ms) uniformly broad proximally, strongly narrowed in its distal third and bent posteriad (Figs 28, 29); solenomerite (S) broad, with scattered setae on posterior margin, narrowing at mid-length, and bearing a large blunt process (pr); solenomerite apically with a broad folded lamella (Fl) and a small wrinkled lamella laying on the top of a slender and slightly protruding process (ds) housing the distal part of the seminal groove (g); seminal groove running from the fovea (F) and opening at the apex of process ds (Fig. 28). Paracoxite (Px) stout, distally curved mesad and narrowed into a slender apex pointing basad emerging from a broad and rounded coxite (Co) (Fig. 30).

Distribution.

Exact locality unknown. The label mentions ‘Tunis’ which presumably refers to Tunisia in general.

Habitat.

Unknown.

Remarks.

The collector of this species, J.P. Coindé, who was a ‘zoologist-traveler’, made a collecting trip to Tunisia in 1861 during which he visited several localities throughout the country. Although we are certain that Ommatoiulus xenos sp. n., found by chance in an obscure jar among several unidentified myriapods from North Africa, labelled 'Brolemann unidentified’, was collected in Tunisia, we couldn’t determine with certainty the locality where this species was collected 152 years ago.