Procophorella, Mesibov, Robert, 2003

Mesibov, Robert, 2003, Two new and unusual genera of millipedes (Diplopoda: Polydesmida) from Tasmania, Australia, Zootaxa 368, pp. 1-32 : 2-3

Procophorella n. gen.

Type species: Procophorella innupta n. sp.

Further assigned species: P. b as hf ordi n. sp.

Diagnosis: Small, cylindrical dalodesmoids with head + 19 segments and no sphaerotrichomes; paranotum reduced to a very narrow, upwardly concave ledge on most segments; pore formula 5, 7–18; gonopod telopodites not fused, slightly swollen at base, rapidly tapering to caudally curved structure with short, acuminate, apical solenomerite and with terminal or subterminal, blade­like processes directed proximad. Readily distinguished from the similar and co­occuring dalodesmoid genus Paredrodesmus by the presence of paranota on posterior segments.

Description: Male ca. 9 mm long, ca. 0.8 mm maximum vertical diameter. In alcohol, many adults ( Fig. 1 ) uncoloured or very pale; well­coloured individuals a pale reddishbrown in overall appearance; darker reddish­brown on vertex, on collum margin, on posterior margin of metazonites, on antennomeres 2–7 and on distal podomeres beginning with femur. Head with antennal sockets well­impressed, antennal bases separated by ca. 1.5 times their diameter. Antennomere length decreasing in the order 6, 3, 2, 4, 5; antennomere 6 greatly inflated ( Fig. 2 C). Collum narrower than head, anterior margin straight, posterior margin weakly emarginate, corners rounded. From above, somites 2 and 3 narrower than collum, somite 4 about as wide as collum, more posterior somites somewhat wider. Somite 2 with paired ventral ‘teeth’ near posterior margin ( Fig. 2 A); ‘teeth’ also present in females and older juveniles. Somites with strong constriction between pro­ and metazonite and a weak transverse constriction dividing the metazonite into an anterior and posterior portion; a transverse row of short, sparse setae in the middle of each metazonite portion and near the posterior margin of the metazonite; somite surface otherwise smooth, untextured. Paranotum on somite 2 a distinct flange at the level of the collum corner; paranota on somites 3 and 4 less distinct, higher; paranota of somites 5–15 represented by a very narrow, upwardly concave ledge with a slight lateral thickening, the ledge higher anteriorly ( Figs. 2 B, 3); no apparent ledge on 16–18. Ozopores on somites 5, 7–18, opening at the posterior end of the paranotal ledge ( Fig. 3 ); ozopore rims refracting light strongly and appearing like dewdrops or tiny glass beads under low magnification. Sternites longer than wide, slightly wider anteriorly; coxae on somite 6 spaced well apart to accommodate flexed gonopod telopodites. Legs somewhat incrassate, more so anteriorly, the postfemur and tibia relatively short ( Fig. 2 D); ventral leg setae short, dense; no sphaerotrichomes on any legs. Anterior spiracle on diplosegments directly over anterior leg, posterior spiracle midway between legs. Pre­anal ring lightly setose; hypoproct paraboloid in outline; epiproct tapering to a broad point, extending past the anal valves and with several long setae. Genital opening on leg 2 coxa on a short, prominent, truncated cone. Gonopod aperture about half the width of the prozonite, wider than long, the margin straight anteriorly and strongly curved posteriorly, the aperture ‘tilted’ with the anterior margin distinctly lower than the posterior margin when seen from below. Gonopod coxae enclosed within gonopod cavity and well separated from aperture margins. Coxae rounded, tapering distally, lightly joined along mesal surface. Cannula prominent, inserting in shallow depression in base of telopodite. Telopodites pressed close together in situ but not fused, extending when flexed to the coxae of legpair 6. Telopodite tapering from the base and curved caudally and slightly laterally, with moderately dense setation on the proximal surface of the swollen base but only a few setae distally. Prostatic groove running along the mesal side of the telopodite for about half its length before crossing the posterior surface and continuing on the lateral surface; solenomerite a short, acuminate process on the lateral side of the telopodite tip. Other telopodite processes terminal or subterminal, short, blade­like and directed proximad, also a narrow, variably long, terminal or subterminal, spur­like process more mesally. Female somewhat longer and stouter than male; epigynum inconspicuous, the posterior rim slightly raised in the middle; cyphopods not examined.

Etymology: Diminutive of Greek prox, dewdrop, + ­ phor, bearing; feminine gender. So named because the ozopores gleam like dewdrops in reflected light.

Remarks: The two known species of Procophorella are indistinguishable as females and juveniles and are very similar in gonopod form. However, the differences in gonopod details, though minor, are consistent over the ranges of the two species. The two species distributions appear to meet at the Mersey Break, a linear biogeographical divide in north central Tasmania ( Mesibov 1999; see also Fig. 5 ).

Figures

FIGURE 1. General views of females of Procophorella innupta n. sp. (left) and Paredrodesmus sp., probably P. taurulus n. sp. (right). Both specimens are ca. 10 mm long.

FIGURE 2. Procophorella innupta n. sp. (A) somite 2, anterior view showing ventral ‘teeth’ (t), female, QVM 23:41523; (B) somite 12, posterior view, male, QVM 23:41420; (C) antenna, male, QVM 23:41420, apical cones and setation not shown; (D) somite 12 leg, female, QVM 23:41493, setation not shown. All drawings to same scale.

FIGURE 3. (Left) Procophorella innupta n. sp., lateral SEM view of mid­body paranotal ledge and ozopore, female, QVM 23: 41469; scale bar = 0.3 mm. (Right) Paredrodesmus bicalcar n. sp., lateral SEM view of mid­body ozopore, male, QVM 23: 41197; scale bar = 0.04 mm.

FIGURE 5. Distributions in Tasmania of Procophorella bashfordi n. sp. (crosses), P. innupta n. sp. (large squares) and unidentified Procophorella females and juveniles (small squares). Circled locality in northeast Tasmania is Old Chum Dam (see text).