Pseudopolydesmus caddo, CHAMBERLIN, 1949

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 : 136-137

PSEUDOPOLYDESMUS CADDO CHAMBERLIN, 1949

( FIGS 26–28 )

Pseudopolydesmus caddo Chamberlin, 1949: 97 , fig. 11, ♂ / ♀ ST (USNM, vidi). – Chamberlin & Hoffman, 1958: 69. – [ Withrow, 1988: 115, figs 50, 77, 96, 100, 104, 116, 118, 122–126, map 9, tables 9–11.] – Hoffman, 1999: 442 (= Ps. bidens ).

Pseudopolydesmus bidens Loomis, 1959: 161 , fig. 8, ♂ HT (USNM, vidi).

Diagnosis

Size: Small, with body length ranging from 7.5 to 13.3 mm and an average body length of 10.0 mm (N = 28; Withrow, 1988: 119). Comparable in size to Ps. minor and Ps. paludicolus , clearly smaller than all other congeneric species.

Paranota and tergal sculpture ( Fig. 26 ): Corners of paranota forming a roughly trapezoidal quadrilateral, with lateral edge longer than medial edge, giving the paranota a characteristic flared-out appearance. Leading margin moderately curved, distal margin nearly straight, trailing margin strongly concave. Anterior lateral corner and denticles always strongly distinct. Anterior blister row thicker medially than MB row, MB row thicker than PB row. Median blister 2 much larger in area than MB1. Tergal blisters poorly differentiated, PB row nearly obliterated except lateral sulcus of PB3. Central paranotal blisters occupying two-thirds of paranotal breadth. Lateral blisters aligned with longitudinal axis.

Gonopod ( Figs 27 , 28 ): Gonocoxa ventral lobe with single gonocoxal plate. Telopodite uniformly curved. Pulvillus elongate, pointed, midway between base and terminus of acropodite. Processes e1, e2, e4 and m3 absent. Process e3 projecting from a flanged ectal lamina ( Fig. 28B ). Processes m1, m2 and m4 all medium-sized, subtriangular; m1 at base of pulvillus; m2 connected to e2 via weak transverse ridge (not as distinct as in Ps. serratus ); m4 proximal to terminal bristles. Our process m4 might be homologous to e 4 in other Pseudopolydesmus : it is located subterminally on the acropodite and, in both the Ps. bidens and Ps. caddo type specimens, does not bear proximal bristles (although the specimens may have been damaged).

Type notes

Pseudopolydesmus caddo (two ♂ and one ♀ ST, USNM, vidi): From 5 miles northwest of Shreveport , Caddo Par., LA, USA, collected 13 April 1936 by L. Hubricht . Two ♂ ST both with gonopods removed; one is erroneously labelled ‘HT’ with gonopods in genitalia vial, left gonopod with tip broken off. ♀ ST labelled ‘Lectoallotype’.

Pseudopolydesmus bidens (♂ HT, six ♂ and five ♀ PT, USNM, vidi): Loomis, 1959 nominated ♂ HT and described six additional ♂ and five ♀ from site between Kinder and Le Blanc , Allen Par., LA, USA collected 20 December 1958 by E. M. Loomis and H. F. Loomis . We found one type lot containing one small vial labelled ‘Holotype’, one male with gonopods in situ, one male with gonopods dissected into a genitalia vial and one intact female. Holotype vial contains complete male with both dissected gonopods.

Distribution

Coast and coastal plain of the Gulf of Mexico, from eastern Texas to southern Mississippi.

Figures

Figure 26. Pseudopolydesmus caddo, metatergite and paranota of body ring 10. Paratype, adult male (USNM, ultraviolet enhancement).

Figure 27. Gonopod of Pseudopolydesmus caddo. Holotype (USNM). A, right gonopod, ectal view. B, right gonopod, medial view.

Figure 28. Gonopod of Pseudopolydesmus caddo. Holotype (USNM, ultraviolet enhancement). A, right gonopod, ectal view. B, right gonopod, medial view.