Antichiropus gibbus Car, 2019

Car, Catherine A., Harvey, Mark S., Hillyer, Mia J. & Huey, Joel A., 2019, The millipede genus Antichiropus (Diplopoda: Polydesmida: Paradoxosomatidae), part 3: species of the Pilbara bioregion of Western Australia, Zootaxa 4617 (1), pp. 1-71 : 33-35

Antichiropus gibbus Car , n. sp.

( Figs 16 , 18 A–F)

ZooBank: urn:lsid:zoobank.org:act:76F3D7B5-6021-4E80-A4AF-FEEF47DFFC3A

Type material examined. Australia: Western Australia: holotype male (damaged), Auski Road House, at junction of Great Northern Highway / Munjina-Wittenoom Roads, 22°53’13”S, 118°38’27”E, 17 June–29 July 2008, wet pitfall trap, E.S. Volschenk and L. Quinn (WAM T144578). Paratypes: 1 juvenile, collected with holotype (WAM T94688); 2 females, 6 juveniles, collected with holotype (WAM T146714).

Other material examined. Australia: Western Australia: 2 juveniles (damaged), Auski Road House, at junc- tion of Great Northern Highway /Munjina-Wittenoom Roads, 22°53’13”S, 118°38’27”E, 17 June–29 July 2008, by hand, E.S. Volschenk and CA. Taylor (WAM T94686); 1 female (damaged) collected with holotype (WAM T94687, GenBank accession number 12S, MK735746 ; 28S, MK735810 ); 2 juveniles, collected with holotype (WAM T94689).

Diagnosis. Gonopod: There are three Antichiropus species in the Pilbara region, A. gibbus Car, n. sp., A. echi- nus Car, n. sp. (Fig 13) and A. hystricosus Car, n. sp. (Fig 19) in which there are short pointed ‘pegs’ or teeth present on the base of the solenomere. Antichiropus gibbus is easily recognised because the gonopod carries a pronounced protuberance on the apical 1/3 of the femorite, entirely lacking in the other two species.

Description. Male holotype: Body ca. 10 mm long; midbody ring ca. 1.5 mm wide, with distinct, smooth waist, prozonite and metazonite of similar widths.

Colour (in alcohol) chestnut brown (Fig 18A); leg colour paler than body. No paranota (Fig 18B) Sternites without obvious processes/tubercles, sternal lamella of moderate width, M-shaped. Leg coxal processes absent. Anterior spiracles at midbody small, flat.

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Head smooth, with no sculpturing; frons smooth, with few setae; face narrow, maximum width ca. 3x the distance between antennal sockets; sockets separated by ca. 2x width of socket.

Antennae relatively long, reaching to ring 3, antennomeres robust.

Collum 1x as long as head (in lateral view) ( Fig 18A ).

Gonopod of medium length, reaching posterior edge of ring 5; coxa (C) similar in length to femorite but much more robust, with distinct ridge on anterior surface; prefemur (PF) similar in length to femorite, prefemoral lip pronounced; femorite (F) short, squat, arising from prefemur at an angle; main femoral process (MFP) broad at base tapering to a fine point; second femoral process (fp1) absent; pronounced protuberance on apical 1/3 of femorite; prolongation of femorite (prof) curved, relatively slender, tapering to a point, mostly horizontal in orientation; solenomere (S) moderately long, forming a circle, relatively stout at base, but much more slender than femorite, covered with short spines from its base for 1/4 its length; solenomere process (sp1) in apical 1/3 of solenomere, slender, curved and pointed ( Figs 18 C–F).

Female: Very similar to male, but very slightly broader when viewed dorsally (ca. 2 mm) and stouter when viewed laterally; legs shorter and more slender (WAM T94688).

Distribution. To date, known only from the immediate area surrounding the Auski Roadhouse, at junction of Great Northern Highway /Munjina-Wittenoom Roads, near Mt. George ( Fig 16 ).

Remarks. It is difficult to see the solenomere tip without destroying a gonopod on the only male specimen: the soltip appears to be flattened with a blunt end (not seen in images).

Etymology. The species is named for the noticeable protuberance on the gonopod femorite (Latin, adjective, gibbus , humped, protuberant).

Figures

FIGURE 16. Map showing the known distributions of A. cunicularis Car, n. sp., A. echinus Car, n. sp., A. filiolus Car, n. sp., A. forcipatus Car, n. sp., A. georginae Car, n. sp., and A. gibbus Car, n. sp.

FIGURE 18. Antichiropus gibbus Car, n. sp., holotype male (WAM T144578): A–B habitus: A, lateral view; B, dorsal view; C–F, left gonopod: C, posterior view; D, anterior view; E, medial view; F, lateral view. Abbreviations: F, femorite; MFP, main femoral process; PF, prefemur; prof, prolongation of femorite; S, solenomere; sp1, solenomere process1. Scale bars: A = 2 mm; B = 2 mm; C–F = 0. 5 mm.