Pseudopolydesmus serratus, SERRATUS (SAY, 1821)

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 : 138-140

PSEUDOPOLYDESMUS SERRATUS ( SAY, 1821)

( FIGS 8 , 32 , 33 )

Polydesmus serratus Say, 1821: 106 , type material not extant. – Gervais, 1847: 105. – de Saussure, 1860: 325. – Peters, 1864: 539. – Bollman, 1887b: 620 (?= Po. pennsylvanicus ). – Williams & Hefner, 1928: 112, fig. 13b.

Pseudopolydesmus serratus – Attems, 1940: 141, uncertain placement. – Chamberlin, 1943c: 18. – Chamberlin, 1951: 27. – Causey, 1952: 6. – Chamberlin & Hoffman, 1958: 71. – Loomis, 1959: 161. – Ramsey, 1966: 339. – [ Withrow, 1988: 103, figs 12, 45, 46, 48, 57, 59, 63, 66, 67, 69, 78, 81, 94, 98, 102, 120, 122–126, map 8, tables 9–11.] – Hoffman, 1999: 446 (= Po. scopus ; Po. planicolens ). – Shelley, 2000: 246. – Shelley & Snyder, 2012: 6, figs 2–4.

Polydesmus canadensis – Wood, 1865: 216, figs 43, 44. Mistaken identity!

Pseudopolydesmus canadensis – Attems, 1898: 480, fig. 244. – Verhoeff, 1931: 305, figs 1–7. – Attems, 1940: 140, fig. 201. Mistaken identity!

? Polydesmus pennsylvanicus C. L. Koch, 1847: 133 , type material unknown.

Polydesmus pensylvanicus [sic] – C. L. Koch 1863b: 18, pl. 69: fig. 142.

Polydesmus scopus Chamberlin, 1942a: 16 , fig. 1, ♂ HT (USNM, vidi).

Pseudopolydesmus scopus – Chamberlin & Hoffman, 1958: 71.

Polydesmus planicolens Chamberlin, 1942a: 16 , fig. 2, ♂ HT (USNM, vidi).

Pseudopolydesmus planicolens – Chamberlin & Hoffman, 1958: 71.

Diagnosis

Size: Usually large, with body length ranging from 13.2 to 32 mm and an average body length of 22.7 mm (N = 500; Withrow, 1988: 108, 199). Comparable in size to Ps. canadensis and Ps. erasus , usually larger than Ps. collinus and Ps. pinetorum .

Paranota and tergal sculpture ( Fig. 32 ): Corners of paranota forming a trapezoid, with the anterior (AMC to ALC) edge longer than the posterior (PMC to PLC) edge. Ratio of anterior to posterior edge length larger than in Ps. erasus . Leading and distal margins moderately curved, similar to Ps. erasus but less curved than Ps.canadensis and Ps.collinus . Denticles moderate to obliterated. Trailing margin concave, moderately curved. Anterior and median blister rows subequal in thickness, AB and MB rows much thicker than PB row. Median blister 2 only slightly larger in area than MB1, individual PBs subequal in area. Central paranotal blisters occupying two-thirds of paranotal breadth. Lateral blisters anteriorly widening laterad.

Gonopod ( Figs 8 , 33 ): Gonocoxa ventral lobe with two gonocoxal plates stacked dorsoventrally ( Fig. 33A ). Telopodite slender, kinked at pulvillus, strongly curved terminally. Pulvillus medium-sized, rounded, midway between base and terminus of acropodite. Processes e1, e3, m3 and m4 absent. Process e2 large, subtriangular, connected to m2 via prominent transverse ridge ( Fig. 8 ); e4 small, surrounded by terminal bristles ( Fig. 33A ). Process m1 medium-sized, medial of pulvillus; m2 large, subtriangular ( Fig. 33B ).

Type notes

Polydesmus serratus (non vidi): Type material no longer extant. According to Hoffman (1999), Say collected millipedes on Assateague and Chincoteague Islands, off the eastern shore of Virginia. New collections from this area could serve as material to designate a neotype. In his description, Say noted that this species was found under the bark of Pinus variabilis (Aiton) Lamb. , now a synonym of Pinus echinata Mill. , shortleaf pine ( Govaerts, 2019).

Polydesmus pennsylvanicus (non vidi): Type material unknown, from ‘Pensylvanien’.

Polydesmus scopus (♂ HT, USNM, vidi): From Ledges State Park , Boone Co., IA, USA, collected 19 May 1941 by D. T. Jones . ♂ HT in fragments with one loose gonopod. Chamberlin (1942a) mentioned one female collected nearby but expressed doubt in its identity.

Polydesmus planicolens (♂ HT, USNM, vidi): From Ames, Story Co., IA, USA, collected spring 1941 by D. T. Jones . ♂ HT fragmented with gonopods in small vial, gnathochilarium dissected.

Distribution

Minnesota east to southern Quebec, south to northern South Carolina, west to east Texas. Absent from Georgia and peninsular Florida.

Additional specimens examined

FMNH INS 1413, 1416, 1423, 1436, 1441, 1443, 1452, 1453, 1454, 1495, 1513, 1514, 1517, 1559, 1572, 1576, 2817 *, 2818, 2819 *, 2820, 2821, 2823, 2827, 2828, 2829, 2832, 2833, 2835, 4814, 7103, 7104, 7109, 7185, 7207, 7312, 7316, 7348, 7363, 7366, 7373, 7384, 7390, 7490, 8238 *; VTEC MPE01173 * .

Figures

Figure 8. Body ring 7 in adult male Pseudopolydesmus serratus, posterior view, showing gonopods and sternal tubercles of leg pair 9 (FMNH INS8238, ultraviolet enhancement). Note the prominent transverse ridge between processes e2 and m2 in the gonopods of Ps. serratus.

Figure 32. Pseudopolydesmus serratus, metatergite and paranota of body ring 9. Adult female (FMNH INS2817, ultraviolet enhancement).

Figure 33. Gonopod of Pseudopolydesmus serratus (FMNH INS2819, scanning electron micrograph). A, left gonopod, ectal view. B, left gonopod, medial view. Both images mirrored to appear as right gonopod.