A review of the family Trichopolydesmidae in North Africa with a description of a new species from Tunisia

Abstract A new species of the genus Haplocookia Brölemann, 1915 is described from Cap Bon Peninsula in Tunisia (North Africa) and a historical account of the poorly understood genera Haplocookia and Heterocookia Silvestri, 1898 is provided. Comments on the taxonomy of the family Trichopolydesmidae are presented, as well as an identification key to the trichopolydesmid species hitherto known from North Africa and an updated list of the Polydesmida in the region.


Introduction
The order Polydesmida Leach, 1815 is represented in North Africa with five families, nine genera, and 22 species (see list below). Most of these species are endemic, marginally studied, and the taxonomy of several species and genera remain far from adequate (see Brölemann 1921, Schubart 1960, Tabacaru 1975, Mauriès 1984, Hoffman 1980, Akkari and Enghoff 2011, Enghoff et al. 2015. Among these, the genera Haplocookia Brölemann, 1915 andHeterocookia Silvestri, 1898, represented with four endemic species, have particularly been subject to taxonomic controversies and remain poorly understood in comparison with the rest of the polydesmidans in this region. The genus Haplocookia is characterised by a deeply divided gonopod telopodite bearing short and simple processes. It was first established by Brölemann (1915) to accommodate Haplocookia mauritanica, he then described from Kabylie, Algeria. The genus remained monotypic until Schubart (1960) described Haplocookia franzi from Morocco. Haplocookia franzi Schubart, 1960 differs from the type species in the shape and processes of the distal part of the telopodite.
The genus Heterocookia was described much earlier, based on a species collected and described from Aϊn Draham Region in northwestern Tunisia by Silvestri (1896), Heterocookia novator (Silvestri, 1896). The genus counts a second species, Heterocookia tunisiaca Ceuca, 1967 described from Le Kef (Ceuca 1967). Both genera were first placed with six other genera in the tribe Trichopolydesmini (Brölemann 1915). Subsequently, Attems (1940) considered Haplocookia as a junior synonym of Heterocookia Silvestri, 1898, listing the species mauritanica under the genus Heterocookia in his Tierreich volume on Polydesmoidea. Two decades later, Schubart (1960) re-established Haplocookia as a valid genus, placed it in the family Vanhoeffeniidae Attems, 1914 and described a third species, H. franzi from several localities in Morocco. After two more decades, Hoffman (1980) also considered Haplocookia as a valid genus although he listed only one of the two described species, and assigned both Haplocookia and Heterocookia to the family Polydesmidae Leach, 1815. Mauriès (1984) was the last to discuss the taxonomy of the genus Haplocookia and he recommended placing it back in the family Trichopolydesmidae as previously suggested by Brölemann (1915) and Tabacaru (1975). Golovatch (2013) accepts both Haplocookia and Heterocookia in Trichopolydesmidae but in the latest taxonomic overview of the order Polydesmida, the genus Haplocookia is absent, whereas Heterocookia is listed under the family Trichopolydesmidae (Enghoff et al. 2015).
In this paper, we shed light on this obscure genus, describe a new species from Tunisia, Haplocookia enghoffi sp. n., and we further provide an updated checklist of the polydesmidan fauna of North Africa and an identification key to the species of Haplocookia and Heterocookia in this region.

Material and methods
The material of the new species was collected by NA, stored in 70% ethanol, and deposited in the Muséum national d'Histoire naturelle (MNHN), Natural History Museum of Denmark, Zoological Museum -University of Copenhagen (ZMUC), and Naturhistorisches Museum Wien (NHMW). Type material of Haplocookia mauritanica (MNHN) was examined for comparison. General characters were studied with a Wild Heerbrug 308700 stereomicroscope from Zeiss. Measurements and drawings were obtained using a camera lucida of a compound microscope Axioskop from Zeiss. Parts of some specimens were mounted on microscope preparations in lactic acid for examination. Micrographs were made in NHMW with a Nikon DS-F2.5 camera mounted on a Nikon SMZ25 stereomicroscope, using NIS-Elements Microscope Imaging Software with an Extended Depth of Focus (EDF) patch. All images were processed with Adobe Photoshop CS6 and assembled in Adobe InDesign CS6. Diagnosis. A small polydesmidan of the genus Haplocookia, differing from its congeners in the shape of the distal part of the gonopod telopodite having simple curved processes.

Taxonomy
Etymology. The species epithet honours Prof. Henrik Enghoff, a leading expert in myriapod systematics, author of major works on millipede taxonomy, and always a dear friend.
Collum ( Figure 2B) semicircular, not broader than head, flattened, with four irregular transverse rows of tubercles bearing stout and long setae, paranotal edges incised into three well-developed lobes, each one bearing 1 seta.   Metaterga ( Figure 2C) with three transverse rows of 10−14 tubercles each bearing a short and stout seta (anterior and posterior rows with ten tubercles each, median row with variable number), median row closer to posterior one.
Telson with two transverse rows of tubercles bearing long and strong setae, epiproct almost triangular, with relatively long setae.
Gonopods (Figure 3). Coxa (Cx) well-developed, hemispherical, internal margin not indented, external border extended in a large anterior rounded lobe with 2 long and 1 shorter setae seen in posterior view. Prefemoral part (p) with strong setae, medially folded and sheltering basal opening of seminal groove. Cannula (C) concealed in coxa, its tip entering mesal fold of the prefemur, where seminal groove (S) arises. Distal part of telopodite divided into solenomere (So) and tibiotarsus (t). Tibiotarsus simple, relatively broad and apically bent, with barely perceptible blunt bump on internal margin. Solenomere (So) slender and bent bearing the opening of the seminal groove at apex. Seminal groove (S) uniformly broad from femoral basis up to apex of solenomere, noticeably thickening at femoral level, just above bifurcation of telopodite.
Comments. H. tunisiaca is reported here for the first time from Algeria.

Notes on the North African trichopolydesmids
Except for the special structure of the seminal groove (a small bulb-like extension, reminding of genus Polydesmus), the gonopod of Haplocookia enghoffi sp. n. is built in the same way as that of H. mauritanica and H. franzi, with a typically polydesmoid crescent-shaped telopodite arising from a large coxa (Figs 3, 5A, B). In all three species, the telopodite is divided into a tibiotarsus and a slender solenomere. However, these two processes show different configurations in the three species (Figs  3, 5A, B). In H. mauritanica, the two processes separate at the apical third of the telopodite and the solenomere is a very slender process orthogonal to the main telopodite axis. In H. franzi, the solenomere is a small and elongated branch, slightly bent and forked, laterally protected by a larger tibiotarsus. The telopodite is clearly indented in H. franzi, presenting a subapical triangular tooth in H. mauritanica, and only a small subapical blunt bump in H. enghoffi sp. n. The genus Heterocookia includes two species from Tunisia, viz. H. novator ( Figure  4A) and H. tunisiaca ( Figure 4B), the latter is recorded here for the first time from El Tarf in Algeria. Both species are larger than the Haplocookia species despite sharing the same external characters. Their gonopods ( Figure 5C, D) are characterised by a deep ramification of the telopodite, which clearly shows three slender processes composed of a simple solenomere, a more complex tibiotarsus, and a third process.  Brölemann, 1915(redrawn after Brölemann 1915) B Haplocookia franzi Schubart, 1960(redrawn after Schubart 1960) C Heterocookia novator (Silvestri, 1896) D Heterocookia tunisiaca Ceuca, 1967. Scale bar 0.1 mm.
Ten years later, Simonsen (1990) underlined a clear geographical discontinuity between the Euro-Mediterranean and the Afrotropical taxa, placing them in Trichopolydesmidae and the Fuhrmannodesmidae, respectively, which was supported subsequently by Shelley (2003). Recently, Shear (2011) provided a list of Trichopolydesmoidea, where the family Trichopolydesmidae was not mentioned, very likely merged with the Fuhrmannodesmidae. Among the latest contributions, Golovatch (2013) reclassified the superfamily Trichopolydesmoidea, presented a diagnosis for the family Trichopolydesmidae, based on male sexual characters and provided a new circumscription of the family in which he included the Fuhrmannodesmidae, Macrosternodesmidae Brölemann, 1916, Mastigonodesmidae Attems, 1914and Nearctodesmidae Chamberlin and Hoffman, 1950. This same classification was also adopted by Enghoff et al. (2015) in their classification of the Polydesmida. The Trichopolydesmidae currently includes around 75 genera and 140 species (see Golovatch 2013), among which nearly 20 genera and 40 species with Euro-Mediterranean distribution, and two genera and five species in North Africa.