Carinobolus complex, 2022

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), Zootaxa 5150 (1), pp. 97-110 : 99-102

Carinobolus complex sp. nov.

Figs 1–3

Material examined. Holotype male ( NHMD), southeastern NIGERIA, 56 km from Calabar , 13.VI.1963, collector unknown.

Paratypes: 1 male, 1 female ( NHMD) , 1 male ( SEM, RMCA), same data as holotype .

Name. Complex, a noun in apposition referring to the particularly complex anterior gonopods.

Diagnosis. Basically as in the genus. Body short, up to 26 mm long, with 38 body rings plus telson. Metazonae bimodally crested, epiproct slightly projecting caudally. Tarsal pads present, coxal projections absent. Legs and antennae short. Anterior gonopods particularly complex, multiramous, rather palm-shaped, with a paramedian pair of antero-apical processes and a two-segmented telopodite.

Description. Measurements: male holotype with 39 body rings (38 + telson), ca 26 mm long, 3 mm wide. Male paratypes same as holotype; female paratype slightly longer than male (ca 28 mm long), broken into several pieces.

Coloration faded in alcohol, but two darker stripes still visible on each side of body. Head, antennae, legs and telson slightly brownish, ommatidia and medial part of frons dark brown ( Fig. 1 ).

Head capsule with a median suture, this being especially distinct on labrum; ca 20 ommatidia located in an irregular oval cluster ( Fig. 2B ). Labrum as usual, with three irregular teeth and a single row of 10–12 stout marginal setae. Clypeus with two setiferous foveolae on each side ( Fig. 2A ). Incisura lateralis closed ( Fig. 2B ). Antennal cavity/groove present, antennae shorter than body diameter. Relative lengths of antennomeres: 3=4=5<1<6<2 ( Fig. 2A, B ). Terminal antennomere with four large sensory cones clustered together inside a membranous area. Antennomeres 5 and 6 each with an apicolateral field of specialized sensilla ( Fig. 2C ).

Gnathochilarium as usual, of spirobolidan conformation. Stipites separated in basal portion, each bearing three apical setae, but not setose on ventral surface. Lamellae linguales separated by anterior portion of mentum ( Fig. 2D ), each with two usual setae located behind one another, mentum devoid of a large swollen area apically between both lamellae linguales, but subdivided basally by a well-marked suture ( Fig. 2D ).

Mandible: external tooth (et) large and prominent, inner tooth (it) with three smaller inner teeth, a thin lateral tooth (lt), five rows of pectinate lamellae (pl), molar plate (mp) with a few (2–3) transverse furrows ( Fig. 2E–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. 2H ).

Body rings: Metazonae heavily crested/ribbed, crests being bimodal, slightly, but clearly concave in the middle ( Figs 1A, B , 2H–K, M, N ); mesozonae with longitudinal impressions, these being especially clearly visible ventrally; pre-anal ring with dorsal tip of epiproct clearly overhanging the paraprocts ( Fig. 2K ); hypoproct rounded; anal valves well-rounded and devoid of spines or setae. Posterior margin of paraprocts in lateral view without distinct lips ( Figs 1D , 2L ). Ozopores (oz) small and inconspicuous, starting with ring 6 ( Fig. 2I ), suture between putative pleurotergite and sternite visible. Pleurotergal tips of body ring 2 gaping ventrally, not connected to sternite; pleurotergal tips of body ring 3 fused to sternite and forming a complete ring. Pleurotergal tips of male body ring 7 fused ventrally. Limbus membranous, overtopped by a row of short, parallel and regularly spaced spinicles ( Fig. 2O ).

Legs: Male leg-pairs 1 and 2 modified, coxae of legs 1 fused medially at base only, each prefemur of legs 2 with a small, unciform, basal projection ( Fig. 3C , hp). Midbody legs ca 0.5 x body diameter, with coxa as long as the other podomeres. Tarsus ventrally with three pairs of spines and apically with a pair of setiform spines ( Fig. 3B ). Male tarsi 3 up to midbody legs with a tarsal pad not protruding past base of claw ( Fig. 3B , pa). Tarsal claw of male leg pair 1 normal in size, subequal to tarsal claws of postgonopodal legs ( Fig. 3A, B ).

Anterior gonopods ( Fig. 3D–F ) especially complex, clearly branched; sternite (st) elongated into a triangular process with a blunt tip; a paramedian pair of slender, membranous, acuminate, antero-apical processes (ap); coxite (cx1) subtending much of anterior gonopods; telopodites 2-segmented, each consisting of a smaller, roundish, basal telopoditomere (t1) and a much larger, higher, complex, lobe-shaped, distal telopoditomere (t2).

Posterior gonopods ( Fig. 3G–I ) connected by a small, triangular, sclerotized sternite (st), clearly and rather regularly curved, slender, 2-segmented, both segments (a thicker and slightly longer coxite (cx2) and a more slender and shorter telopodite (tl) distinctly separated near midway subtransversely by a deep seminal groove; a rudimentary solenomere (sl) subapically. Sperm channel running at mesal margin of coxite through telopodite’s subapical part ( Fig. 3I ).

Vulvae in the single female missing (apparently, removed and lost by Richard L. Hoffman at VNHM).

Figures

FIGURE 1. Carinobolus complex sp. nov., male holotype (NHMD). A. Habitus, lateral view. B & C. Anterior part of body, lateral and ventral views, respectively. D. Posterior part of body, ventral view. Scale bars: 4 mm (A), 1 mm (B–D).

FIGURE 2. Carinobolus complex sp. nov., male paratype (RMCA). A & B. Head, frontal and lateral views, respectively. C. Tip of antenna, sublateral view. D. Gnathochilarium, ventral view. E, F & G. Right mandible, submesal, mesal and subfrontal views, respectively. H. Anterior part of body, lateral view. I. Midbody rings with ozopores (oz), lateral view. J. A midbody metazona showing bimodal crests. K & L. Posterior part of body, lateral and ventral views, respectively. M. Cross-section of midbody ring, frontal view. N. Details of a midbody ring, lateral view. O. Limbus of a midbody ring, lateral view. Abbreviations: et, external tooth; it, internal teeth; lt, lateral tooth; mp, molar plate; oz, ozopore; pl, pectinate lamella. Scale bars: 500 µm (A, I, K, L, M), 200 µm (B, D, H, J), 100 µm (C, E, F, G, N), 10 µm (O).

FIGURE 3. Carinobolus complex sp. nov., male paratype (RMCA). A. Midbody leg, lateral view. B. Apical parts of a postgonopodal leg with a tarsal pad, subventral view. C. First three legs, ventrocaudal view. D & E. Anterior gonopods, posterior and anterior views, respectively. F. Left anterior gonopod, lateral view. G. Right posterior gonopod, lateral view. H. Posterior gonopods, caudal view. I. Drawing of right posterior gonopod, caudal view. Abbreviations: ap, antero-apical process; cx1, coxite of anterior gonopod; cx2, coxite of posterior gonopod; hp, basal projection of prefemur 2; pa, tarsal pad; sl, solenomere; st, sternite; t1 and t2, telopoditomeres 1 and 2; tl, telopodite. Scale bars: 200 µm (A, E, F, G), 50 µm (B), 500 µm (C, D), 0.5 mm (H, I).