Rhicnostethus rondoni, 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 : 52-54

Rhicnostethus rondoni n. sp.

( Figures 21-25)

Material: Male holotype and three male paratypes ( MZUSP) from Nova Esperança (11.32S, 61.07W), Edo. Rondônia, Brazil , 6-8 December 1983, leg. P.E. Vanzolini (field number MZ-Polonoreste 83-1888). Male paratype ( VMNH) from Nova Brazilia , Rondônia ,

PAP. AVULS ZOOL. 46(5), 2006 53

6-11 November 1984, Vanzolini (MZ-Polonoreste 84.0565).

Name: Commemorating the contributions to Brazilian natural history of C.M.S. Rondon.

Diagnosis: With the characters of the genus, distinguished from R. coriaceus in color, prozonal texture, absence of pleurosternal carinae, and longer prefemoral process of the gonopod.

Holotype: Adult male, ca. 47 mm in length, body widest near anterior end, thereafter gradually narrowed back to about 14 th segment, W/L ratio at midbody, 18%; widths of selected segments:

Segment

4 – 9.0 mm

6 – 9.3

10 – 8.8

12 – 8.7

14 – 8.5

16 – 8.2

18 – 5.7

Original color in life unknown, faded specimen suggesting dark brown or maroon dorsum with entire upper surface of paranota, legs, and antennae yellow.

Head unmodified, epicranium and genae microvermiculose, frons and labrum smooth; width across genae 4.7 mm, interantennal space 1.1 mm. Epicranial setae 1-1, interantennal, 1-1, frontal 1-1, clypeal 5-5, labroclypeal about 8-8, continuous laterally with 5-5 marginal genal setae. Antennae 9.2 mm, articles 2-6 subequal in length and shape, 6 th without distal sensory groove, but with a glabrous area beset with microsetae in its place; 7 th without lateral sensory knob, apical cones divided into two diads.

Dorsal surface of all metaterga, except lateral third of paranota, densely microgranulose, individual granules round to suboval, closely spaced but not in contact. No trace of transverse sulcus or seriate tubercles. Prozona smooth, stricture prominent on all segments but with distinct anterior edge only on segments 2-4. Paranota of segments 1-3 declined ventrad, 4 th and those following more nearly horizontal and set high, transverse to body axis, subrectangular on anterior segments, posterior corner produced from 4 th onwards. Anterior edge of paranota with prominent high rim, caudal edge not elevated, slightly serrulate, paranotal shape as in Figs. 21-22. Ozopores in normal sequence, displaced inward from lateral edge with resultant subtriangular peritreme area. Paranota of segment 19 abruptly smaller, elongate oval; epiproct subconical, of typical polydesmoid shape. Paraprocts vertically striated; hypoproct transversely triangular, with acute median projection, paramedian tubercles obscure.

Sternal areas of metazona moderately elevated as podosterna, 1.7 mm wide at midbody, produced into a low conical projection just behind each coxal condyle, sternal surface prominently striate-ridged longitudinally. Sides of metazona evenly and uniformly microgranulate, without trace of pleurosternal carinae. Stigmata small, elongate-oval, each placed just anterior to dorsal coxal condyles.

Legs moderately long, ca 8.2 mm at midbody, of normal shape for the family, podomere lengths 3>6>5=2=4>1, basal podomeres nearly glabrous except small sparse ventral setae on femora, distal three with stiff brown setae on all surfaces. Anterior legs without enlarged podomeres or subtibial pads, but distinctly more setose than others. Gonopore opening on apex of an elongate conical projection from 2 nd coxa ( Fig. 23). Sternum of segment 4 reduced to two appressed laminae between 3 rd legs; sternum of segment 5 with two pairs of conical projections, those between anterior legs the larger, posterior cones separated by a deep cleft; segment 6 with similar cones between anterior legs, but surface between posterior excavate, no cones formed.

Gonopod aperture moderate in size, transversely oval, contained entirely in metzonum and not displacing line of stricture midventrally. Lateral ends elevated. Gonopods small, not extended beyond front of 7 th segment, median sternal element rudimentary and displaced, coxae in contact. Coxae short, subglobose, with small acute supracannular apophysis, one dorsal macroseta, no paracannular setae. Telopodite attached at right angle to coxa, nearly straight, prefemoral region half total length of telopodite, with short, distally tridentate prefemoral process on dorsal side; acropodite region set off only by indistinct suture line on lateral side, consisting of large concave lobe on dorsal side conducting prostatic groove along its edge and a slender falcate distal projection ( Figs. 24 and 25).