Pseudopolydesmus collinus, COLLINUS HOFFMAN, 1974

Sierwald, Petra, Hennen, Derek A, Zahnle, Xavier J, Ware, Stephanie & Marek, Paul E, 2019, Taxonomic synthesis of the eastern North American millipede genus Pseudopolydesmus (Diplopoda: Polydesmida: Polydesmidae), utilizing high-detail ultraviolet fluorescence imaging, Zoological Journal of the Linnean Society 187 (1), pp. 117-142 : 131-132

PSEUDOPOLYDESMUS COLLINUS HOFFMAN, 1974

( FIGS 15 , 16 )

Pseudopolydesmus collinus Hoffman, 1974: 346 , figs 1, 2, ♂ HT (VMNH, non vidi but see type notes). – [ Withrow, 1988: 98, figs 85, 89, 93, 110, 115, 122–126, map 7, tables 9–11.] – Hoffman, 1999: 444.

? Polydesmus moniliaris – Williams & Hefner, 1928: 112, fig. 13a. Mistaken identification!

Diagnosis

Size: Medium-large, with length ranging from 12.9 to 25.3 mm ( Withrow, 1988: 199) with an average length of 19 mm (N = 40; Withrow, 1988: 101). Often smaller than Ps. canadensis and Ps. serratus . Comparable in size or slightly smaller than Ps. erasus . Usually larger than Ps. pinetorum .

Paranota and tergal sculpture ( Fig. 15 ): Corners of paranota forming a roughly rhomboid quadrilateral, with ALC posterior to AMC and lateral to PLC. Edges meeting at ALC and PMC forming right angles, with posterior edge longer than in Ps. canadensis . Leading and distal margins very rounded, denticles weak. Angle of curve along distal margin and lateral portion of leading margin uniform from PLC past ALC. Trailing margin moderately concave, less so than Ps. serratus . Anterior blister row medially thicker than median blister row, narrowing only slightly at lateral ends. Median blister row thicker than posterior blister row. Central paranotal blisters large, occupying more than two-thirds of paranotal breadth, as wide as long. Lateral blisters anteriorly widening laterad.

Gonopod ( Fig. 16 ): Gonocoxa ventral lobe with single gonocoxal plate. Telopodite curved and slightly thickened basal to pulvillus, nearly straight beyond pulvillus, with a subterminal kink followed by straight terminal section. Pulvillus medium-sized, midway between base and terminus of acropodite. Process m3 absent. Process e1 reduced to near absence; e2 large, recurved, combined on short, thick stalk with large, subtriangular e3 ( Fig. 16C ); e4 small ( Fig. 16A ). Process m1 small, medial of pulvillus; m2 large, subtriangular; m4 typically shaped, well separated from m2 of a similar size ( Fig. 16B ).

Type notes

(♂ HT, non vidi; five ♂ PT and eight ♀ PT, VMNH, vidi): From Pinnacles of Dan , ~ 4 miles southwest of Vesta, Patrick Co., VA, USA, collected 22 April 1972 . We found one jar at VMNH labelled ‘PARATYPE’, containing two vials. One vial contained five ♂ PT ( VMNH PSE00044); the other vial contained eight ♀ PT ( VMNH PSE00043). The ♂ HT might be included in the vial of ♂ PT without a label. Two male paratype specimens from VMNH PSE00044 were individually relabelled and imaged ( VMNH PSE00202 * and VMNH PSE00203 *).

Distribution

Southern Indiana east to West Virginia, south to central Virginia and north-central South Carolina. Williams & Hefner (1928) reported Polydesmus moniliaris C. L. Koch, 1847 as common and abundant throughout the state of Ohio. Based on their figure (fig. 13), Withrow (1988) suggested that this was a misidentification of Ps. collinus , although the figure lacks detail and most probably depicts Ps. canadensis , which also occurs in Ohio.

Figures

Figure 15. Pseudopolydesmus collinus, metatergite and paranota of body ring 9. Paratype, adult male (VMNH PSE00202, ultraviolet enhancement).

Figure 16. Gonopod of Pseudopolydesmus collinus. Paratype (VMNH PSE00203, ulatraviolet enhancement). A, left gonopod, ectal view. B, left gonopod, medial view. C, left gonopod, posterior oblique view, showing fusion of e2 and e3 processes onto a short, thick stalk. All images mirrored to appear as right gonopod.