Pseudopolydesmus canadensis, CANADENSIS (NEWPORT, 1844)

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 : 127-131

PSEUDOPOLYDESMUS CANADENSIS ( NEWPORT, 1844)

( FIGS 7 , 13–14 )

Polydesmus canadensis Newport, 1844: 265 , immature ♀ HT (BMNH, non vidi). – Gervais, 1847: 106. – de Saussure & Humbert, 1870: 52.

Pseudopolydesmus canadensis – [ Withrow, 1988: 89, figs 55, 61, 70–73, 76, 109, 114, 122–126, map 6, tables 9–11.] – Hoffman, 1999: 443 (= Po. glaucescens ; Po. nitidus ; Po. branneri ; Po. echinogon ; Po. conlatus ; D. sylvicolens ; D.christianus ; D. catskillus ; D.phanus ; D. gausodicrorhachus ). – Shelley, 2000: 246.

Polydesmus glaucescens C. L. Koch, 1847: 133 , types unknown. – Koch, 1863a: 59, pl. 26: fig. 51.

Pseudopolydesmus glaucescens – Attems, 1940: 141, uncertain placement.

Polydesmus nitidus Bollman, 1887a: 45 , ♂ / ♀ ST (not located at USNM, non vidi).

Dixidesmus nitidus – Chamberlin & Hoffman, 1958: 67.

Polydesmus branneri Bollman, 1887b: 620 , ♂ HT (USNM, vidi). – Loomis, 1943: 405, fig. 16, pl. 1: fig. 4.

Dixidesmus branneri – Loomis & Hoffman, 1948: 54 (= Polydesmus conlatus ; Dixidesmus christianus ). – Hoffman, 1950: 223. – Causey, 1952: 7. – Chamberlin & Hoffman, 1958: 65.

Pseudopolydesmus branneri – Hoffman, 1974: 346, fig. 3. – Shelley, 1988: 1651, figs 27, 31 (= Dixidesmus catskillus ; D. gausodicrorhacus [sic]).

Polydesmus echinogon Chamberlin, 1942b: 10 , fig. 33, ♂ / ♀ ST (USNM, vidi).

Dixidesmus echinogon – Chamberlin, 1943c: 18. – Chamberlin & Hoffman, 1958: 66.

Polydesmus conlatus Chamberlin, 1943b: 36 , fig. 5, ♂ HT (FMNH INS977, vidi). – Sierwald et al., 2005: 40.

Dixidesmus conlatus – Chamberlin, 1943c: 18.

Dixidesmus sylvicolens Chamberlin, 1943c: 20 , figs 37, 38, ♂ / ♀ ST (USNM, vidi). – Chamberlin & Hoffman, 1958: 67.

Dixidesmus christianus Chamberlin, 1946: 140 , fig. 4, ♂ HT (USNM, vidi). – Chamberlin & Hoffman, 1958: 66.

Dixidesmus catskillus Chamberlin, 1947: 24 , fig. 2, ♂ HT (ANSP, non vidi). – Chamberlin & Hoffman, 1958: 66.

Dixidesmus phanus Chamberlin, 1951: 27 , fig. 1, ♂ HT (USNM, vidi). – Chamberlin & Hoffman, 1958: 67.

Dixidesmus gausodicrorhachus Johnson, 1954: 1 , fig. 1, ♂ HT (USNM, vidi). – Chamberlin & Hoffman, 1958: 66.

Diagnosis

Size: Usually large, with length ranging from 11.8 to 28.6 mm ( Withrow, 1988: 199) and an average body length of 22.2 mm (N = 162; Withrow, 1988: 94). Comparable in size or slightly larger than Ps. erasus and Ps. serratus . Often larger than Ps. collinus . Usually larger than Ps. pinetorum .

Paranota and tergal sculpture ( Fig. 13 ): 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 shorter than in Ps. collinus . Leading and distal margins very rounded, denticles weak to obliterated. 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, median and posterior blister rows subequal in thickness. Anterior blister row narrowing only slightly at lateral ends. Individual MBs and PBs subequal in area. Central paranotal blisters large, occupying more than two-thirds of paranotal breadth, as wide as long. Lateral blisters anteriorly widening laterad.

e2 + e3 large, joined at base into elongate stalk ( Fig. 7 ), sometimes connected by a lamina; e4 small ( Fig. 14A ). Process m1 small, medial of pulvillus; m2, m3 and m4 large, subtriangular, equidistant from each other; m3 offset laterad from m2 and m4 ( Fig. 14B ).

Type notes

Polydesmus canadensis (immature ♀ HT, BMNH, non vidi): Type presumed extant. Collected from Albany River , Hudson Bay , ON, Canada .

Polydesmus glaucescens: Location of types, if extant, unknown. Koch (1847) described the type locality only as ‘Nordamerika’.

Polydesmus nitidus (15 ♂ / ♀ ST, non vidi): Location of type material unknown (not located at USNM). Bollman (1887a) described 15 specimens from Pensacola, Escambia Co., FL, USA.

Polydesmus branneri (♂ HT, USNM, vidi): From Mossy Creek (now Jefferson City), Jefferson Co., TN, USA . Vial contains one male and one dissected gonopod, tip of gonopod damaged.

Polydesmus echinogon (three ♂ and nine ♀ ST, USNM, vidi): Chamberlin (1942b) described four specimens from Shawanese , Harveys Lake , Luzerne Co., PA, USA, collected 23 September 1905 by F. C. Paulmier . We found two type lots, both labelled ‘Types’ by Chamberlin and Gonopod ( Figs 7 , 14 ): Gonocoxa ventral lobe with single gonocoxal plate. Telopodite shallowly curved except at thickened section basal to pulvillus, with subterminal kink followed by straight terminal section. Pulvillus medium-sized, midway between base and terminus of acropodite. Process e1 elongate and kinked; processes with older labels erroneously identifying the specimens as Ps. serratus . Type lot 1 (probably the four specimens described by Chamberlin): contains one male with a single gonopod in situ, one intact female, and two small vials; first small vial labelled ‘MALE HT’ by Withrow, contains one male with a single gonopod in situ and two dissected gonopods (one damaged); second vial labelled ‘Lectoallotype’ by Withrow, contains one fragmented female. Type lot 2: contains five intact females, fragments of two females, one male with a single gonopod in situ, one genitalia vial with a single gonopod. We found two Ps. serratus males with gonopods in situ in Type lot 2 and separated them into a third vial.

Polydesmus conlatus (♂ HT and two ♀ PT, FMNH, vidi; ♂ / ♀ PT, USNM, vidi; additional ♂ / ♀ PT, non vidi): Chamberlin (1943b) nominated ♂ HT and described several male and female specimens from Gatlinburg, Sevier Co., TN, USA, collected 13–19 June 1942 by H. Dybas , and one male and one female from Thomasville, Thomas Co., GA, USA, collected 2 April 1940 by F. Field . The FMNH type lot is from the Gatlinburg locality: contains ♂ HT with gonopods in situ and two ♀ PT, images are available online at https://collections-zoology.fieldmuseum.org/ catalogue/956102, last accessed 25/3/2019 ( FMNH INS 977). At USNM, we found an additional type lot from Greenbrier Cove, Sevier Co., TN, USA: labelled ‘Paratype’, contains at least one female, several males, one dissected gonopod in genitalia vial and one small vial labelled ‘Lectoallotype’; the small vial contains one female with one dislodged vulva. The location of the one ♂ and one ♀ PT from GA is unknown.

Dixidesmus sylvicolens (♂ / ♀ ST, USNM, vidi): Chamberlin (1943c) described ‘many specimens’ from 7 miles north of Sylvania, Screven Co., GA, USA, collected by W. Ivie, 12 April 1943 . We found one type lot: labelled ‘ branneri ’ by Withrow, contains several specimens including males with gonopods.

Dixidesmus christianus (♂ HT, three ♂ PT and five immature PT, USNM, vidi): Chamberlin (1946) nominated ♂ HT and described three ♀ and five immature PT, all from Pass Christian, Harrison Co., MS, USA, collected 15 February 1946 by J. Rapp and W. Rapp . We found one type lot: labelled ‘ branneri ’ by Withrow, contains two intact males, one male with gonopods missing, five immature specimens and one small vial; small vial labelled ‘HT’, contains fragmented male with one gonopod missing. The three ♂ PT we found might represent the three ♀ PT described by Chamberlin.

Dixidesmus catskillus (♂ HT, ANSP, non vidi): From Catskill, Greene Co., NY, USA, collected by Knight .

Dixidesmus phanus (♂ HT and four PT, USNM, vidi): From Suwanee River , FL, USA, without further locality, collected 15 April 1950 by D.E. Beck . We found two type lots. Type lot 1: labelled ‘Male HT’ and labelled ‘ branneri ’ by Withrow, contains one male with gonopods. Type lot 2: contains several female specimens, one with vulvae everted.

Dixidesmus gausodicrorhachus (♂ HT, one ♂ and two ♀ PT, USNM, vidi): From west side of Garnet Lake , Mackinaw Co., MI, USA, collected 31 July 1949 . There are two type lots. Type lot 1: contains ♂ PT with gonopods in situ and one ♀ PT with vulvae everted, nominated by Johnson (1954) as the allotype. Type lot 2: contains ♂ HT with single gonopod and one ♀ PT.

Distribution

Northern Wisconsin east through southeastern Ontario and southern Quebec to the Atlantic Coast, south through the Appalachian Mountains to the Gulf Coast as far west as southern Mississippi.

Additional specimens examined

FMNH INS 1421, 1455 , 1461 , 1465 , 1552 , 1569 , 3574 , 6934 *, 7632 , 7699 , 14219 , 3120683 * .

Figures

Figure 7. Sternal tubercles in male Pseudopolydesmus canadensis, ventral view, body rings 4–8 (FMNH INS6934, ultraviolet enhancement). Visible body rings (BR4–8) and their corresponding leg pairs (LP3–11) and gonopods (GPs) are labelled. Also note the characteristic silhouette of the gonopods of Ps. canadensis, with processes e2 and e3 sharing a narrow stalk.

Figure 13. Pseudopolydesmus canadensis, metatergiteand paranota of body ring 10. Adult male (FMNH INS3120683, ultraviolet enhancement).

Figure 14. Gonopod of Pseudopolydesmus canadensis (FMNH INS6934, scanning electron micrograph). A, left gonopod, ectal view. B, left gonopod, medial view. Both images mirrored to appear as right gonopod. Cannula removed.