Costabolus baculus Golovatch & Vandenspiegel 2022, sp. nov.
Creators: name: Golovatch, Sergei
name: Vandenspiegel, Didier
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Spirobolida
Pachybolidae
Costabolus
Costabolus baculus

description: Costabolus baculus sp. nov.
Figs 4–7
Material examined. Holotype male (with exposed gonopods, body broken into two pieces) (VNHM 198), Nigeria, 27 km NE of Calabar, 20 m inside native forest, 12.VIII.1984, collector unknown.
Paratypes: 2 males (VNHM 198), same data as holotype; 1 female (VMNH 154), Nigeria, 27 km NE Calabar (Ekang road), under logs on fairly dry soil in new canopy forest farmed to young maize, 28.IV.1984, collector unknown; 1 male, 1 female (VMHN 199), Nigeria, 27 km N of Calabar, between trees, native forest, 20 m off logging road, 12.VIII.1984, collector unknown.
Name. Baculus in Latin means “crutch”, referring to the long coxal processes on male legs 2 and 3; a noun in apposition.
Diagnosis. Basically as in the genus. Body short, up to 27 mm long, with 38 body rings plus telson, metazonae with simple longitudinal crests/ribs, epiproct slightly projecting caudally. Male with tarsal pads and prominent coxal projections on leg-pairs 2 and 3.
Description. Measurements: male holotype with 39 body rings (38 + telson), ca 27 mm long, 3 mm wide. Paratypes, both male and female, same as holotype.
Coloration faded in alcohol, but a darker pattern still visible dorsally and laterally, yellowish ventrally. Head, ommatidia and anterior part of collum dark brown, antennae, legs and telson yellowish (Fig. 4).
Head capsule with an axial suture, this being especially distinct on labrum; ca 22 ommatidia located in an irregular oval cluster (Fig. 5A).
Labrum as usual, with three irregular teeth and a single row of 12 stout marginal setae. Clypeus with two setiferous foveolae on each side (Fig. 5E). Incisura lateralis closed (Fig. 5A, D). Antennal cavity/groove present, length of antennae ca 1.3 mm; antennae shorter than body diameter. Relative lengths of antennomeres: 3=4=5<1<6<2 (Fig. 5D). Terminal antennomere with four large sensory cones clustered together inside a membranous area (Fig. 5C). Antennomeres 5 and 6 each with an apicolateral field of specialized sensilla (Fig. 5D).
Gnathochilarium as usual, of spirobolidan conformation. Stipites separated in basal portion, each bearing three apical setae, but no setae on ventral surface. Lamellae linguales separated by anterior portion of mentum, each with two usual setae located behind one another; mentum without a large swollen area apically between both lamellae linguales, subdivided basally by a well-marked suture (Fig. 5H).
Mandible: external tooth (et) prominent, inner tooth (it) with three smaller inner teeth, a thin lateral tooth (lt), six rows of pectinate lamellae (pl), molar plate (mp) with five transverse furrows (Fig. 5F, G).
Collum with a prominent groove along anterior margin, lateroventral margin broadly rounded, not extending ventrad as far as ventrolateral corner of body ring 2 (Fig. 5I).
Body rings: Metazonae heavily crested (Fig. 5J–L); mesozonae with longitudinal impressions, these being especially distinct ventrally (Fig. 5K), caudal fringe/limbus membranous, with very small and regularly spaced spinicles (Fig. 5L). Pre-anal ring with a small dorsal tip of epiproct overhanging the paraprocts (Figs 4A, 5M); hypoproct rounded; paraprocts (anal valves) well-rounded and devoid of spines or setae (Fig. 5M). Posterior margin of paraprocts in lateral view without distinct lips (Fig. 5M). Ozopores (oz) starting with body ring 6.
Legs: Midbody legs ca 1.4 mm long, with prefemur longer than coxa and as long as the other podomeres; with small tarsal pads (pa) (Fig. 5O, P). Male tarsi 3 up to midbody legs with a small tarsal pad not protruding past base of claw, and with a pair of setiform apical spines (Fig. 6D). Male leg-pairs 1, 2 and 3 modified, coxae 1 fused medially at base only, each prefemur 2 with a well-developed, unciform, basal projection (hp) (Fig. 6B, C), each coxa 3 with a long and spoon-shaped coxal process (cp), this being almost as long as the leg itself (Fig. 6B, D).
Anterior gonopods stout and relatively simple (Fig. 6E–I); sternite (st) produced into a wide, broadly rounded lobe, bearing clear traces of axial fusion (Fig. 6E); coxite (cx1) subtending much of anterior gonopods; telopodites basically 2-segmented, each consisting of a smaller, roundish, apically flattened, basal telopoditomere (t1) with a very small, accessory, subtriangular segment at base (Fig. 6H, I), and a much larger, lobe-shaped, distal telopoditomere (t2).
Posterior gonopods (Fig. 6J, K, pg in H) in situ almost completely concealed inside anterior gonopods, clearly divided into a slender coxite (cx2) and a shorter telopodite (tl), both being slender (Fig. 6J) and connected by a tiny triangular sternite. Telopodite consisting of two components: (1) a median membranous area, and (2) a lateral sclerotized area. Sperm channel running at mesal margin of coxite through telopodite’s membranous area, ending up subapically on a rudimentary solenomere (sl) (Fig. 6J, K).
Paratypes. Males as holotype. Female similar in size and appearance to males, but devoid of prefemoral or coxal projections on leg-pairs 2 and 3, respectively. Vulva simple, consisting of two simple, sclerotized plates, bivalve-like and subequal in size (Fig. 7). Both coxite (cxv) and operculum (o) of vulva very small and inconspicuous. Both valves only basally with one row of setae directed towards the opening. Anterior valve (av) slightly larger than posterior one (pv) (Fig. 7).
description: Published as part of Golovatch, Sergei & Vandenspiegel, Didier, 2022, Carinobolus gen. nov. and Costabolus gen. nov., two new, remarkably crested monospecific genera of spirobolidan millipedes from WestAfrica, with the proposal of a new tribe, Amblybolini tribus nova (Diplopoda, Spirobolida, Pachybolidae), pp. 97-110 in Zootaxa 5150 (1) on pages 103-107, DOI: 10.11646/zootaxa.5150.1.5, http://zenodo.org/record/6610039