Lithobiodesmus xenoporus, Hoffman, 2006

Hoffman, Richard L., 2006, Diplopoda From Rondônia, Brazil. Ii. Three New Genera In The Family Chelodesmidae (Polydesmida) R L. H Abstract, Papéis Avulsos de Zoologia (S � o Paulo) 46 (5), pp. 43-55 : 48-51

Lithobiodesmus xenoporus n. sp.

Figures 9-20

Material (all from Edo. Rondônia): Male holotype, male paratype, and female paratype from Nova Esperança, 6-9 December 1983; male and female paratype from Santa Cruz da Serra , 29 November 1983, all P.E. Vanzolini leg., in MZUSP .

Name: From the Greek elements xenos (strange) + poros (pore) in reference to the absence of ozopores from segments 17-19.

Holotype: Adult male, ca. 29 mm long (fragmented), widths of selected body segments as follows:

1 – 4.0 mm 10 – 3.4 mm

2 – 3.9 12 – 3.4

4 – 3.5 14 – 3.3

6 – 3.5 16 – 3.0

8 – 3.5 18 – 2.0

Body widest at anterior end, narrower but parallel-sided over segments 4-12, thereafter becoming attenuated posteriad by reduction in size of paranota which by segment 15 are not as wide as diameter of segment below them. W/L ratio near midbody ca. 13%. Specimen lacking original pigmentation, entirely pale testaceous.

Head capsule smooth and polished, without surface texture; interantennal space 1.0 mm, antennae ca 6.0 mm long, articles in decreasing length order 2>3>6=5=4, basal articles nearly glabrous, 5 th and 6 th uniformly invested in fine declivent setae; 6 th and 7 th without evident sensory pits or fields.

Dorsal surface of collum and all body segments smooth and polished, without trace of tubercles or transverse sulci, laterally strong declivent. Stricture present entirely around body, the anterior edge sharply defined. Paranota of anteriormost segments ( Fig. 9) large, nearly horizontal, anterior corners rounded, posterior acutely angular; from about 8 th segment paranota becoming increasingly smaller ( Fig. 10), ozopores tiny, located near posterior corner, on segments 5, 7, 9, 10, 12, 13, 15-16. Paranota of segment 17 only a fine thin ridge, segment 18 with minute vestige, and 19 without trace of paranota, ozopores absent from all three ( Fig. 11). Epiproct subconical; paraprocts vertically striated; hypoproct triangular, the apex acute, paramedian tubercles obscure.

Metasterna slightly elevated, smooth and glabrous, subconically produced at base of posterior legpair. Sides of metazona smooth, pleurosternal carinae very strongly developed ( Fig. 12) on segments 3-16, projecting beyond caudal edge of segments. Legs ( Fig. 13) long and slender, longest on posterior segments, basal podomeres nearly glabrous, distal two or three with profuse short setae and an apical whorl of enlarged, almost spur-like setae ( Fig. 14). Anterior legs and sterna unmodified except prefemora prominently convex dorsally, and ventral surface of basal three podomeres invested with slender pale setae as long as diameter of podomere. Shape of 2 nd coxa and gonopore in Figure 15.

Gonopod aperture relatively large,transversely oval, extended anteriad to reduce prozonum medially to a thin strip; edges not notably elevated except at lateral ends and immediately anteriad to coxal sockets.

Gonopods joined by a small sclerotized median sternal remnant. Coxae produced laterally beyond base of telopodite, terminating in a shallow rounded ac- Prefemoral setae fine and dense proximally, much longer and more dispersed distally.

Male paratype ( Santa Cruz da Serra ): Substantially larger than holotype, ca 40 mm in length and 5.2 mm wide at midbody, but agreeing closely in gonopodal and peripheral structure except that segment 18 has a slightly more definite carina representing the paranota .

Female paratype (Santa Cruz da Serra): Length ca 29 mm (fragmented), width of segment 2, 4.9 mm, of segment 10, 4.0 mm. Similar to male except: broader sterna, with subcoxal cones greatly reduced; paranota smaller, present on segment 17 only as vague rudiments which do not extend beyond caudal edge of segment.

Base of 2 nd legs and cyphopods ( Figs. 19 and 20). Lateral extension of coxal podomere noteworthy. Receptacle partly sclerotized, but merging proximally into membrane; valves likewise not sharply defined and apparently merging with membrane of gonotheca. Condition of material not permitting more precise drawing and description.

Comments: Schubart (1947:16) has recorded from the Barra do Tapirapé in Mato Grosso a female chelodesmid which from the very brief description seems to have some resemblence to L. xenopus . A reexamination of this specimen as regards its ozopore characters would be desireable .

etabulum (x in Fig. 18) against which a ventral lobe of the postfemoral region pivots, forming a sort of false articulation unknown elsewhere in the family or order.

Two coxal macrosetae on dorsal side, no paracannular setae. Prefemoral region of telopodite continuing long axis of coxa; acropodite set off at an obtuse angle (mesal aspect!) by basal flexure, relatively short, straight, simple, prostatic groove visible for its entire length. Prefemoral process large, bifurcated, one branch straight, broadly laminate with denticulate apex, the other long, recurved around end of acropodite, subdistally broadened, apically acute ( Figs. 16, 17).