Bidentogon expansus Shelley, 2003

Shear, William A. & Marek, Paul E., 2021, Three new genera and eighteen new species of miniature polydesmid millipedes from the northwestern United States (Diplopoda, Polydesmida, Polydesmidae), Zootaxa 4975 (1), pp. 81-126 : 88

Bidentogon expansus Shelley, 2003

Figs 7–12

Bidentogon californicus, Shear, 1972:490 (not of Chamberlin, 1918).

Bidentogon expansus Shelley 2003:11 .

Diagnosis. The expanded tip of the gonopod is bluntly rounded and the solenomere is comparatively long ( Figs 10, 12 ). There are 18 setae in the anterior marginal row on the collum ( Fig. 7 ).

Shelley (2003) provided the new name B. expansus for Shear’s concept of B. californicus . He argued that the types of californicus had been mislabelled, since “Chamberlin’s clear intent, as evidenced by the published account, was to apply this name to the form at Stanford, the designated type locality ( Shelley 2003, p. 10).” Thus, the specimens from Sacramento, on which Shear based his thinking, had probably been somehow mislabelled as the types of californicus . Further evidence that this was correct came from the many records of the real californicus from near the California coast, as opposed to the inland Central Valley around Sacramento.

Here we supplement the original description and illustrations with new SEM pictures ( Figs 7–12 ). The expanded tip of the terminal zone (tz, Fig. 10 ) differentiates this species from B. californicus , otherwise they are very similar.

Distribution. Western Central Valley of California ( Shelley 2003).

New record: CALIFORNIA: Yolo Co.: West Sacramento , 11 April 1961, M. E. Irwin, mmff ( CAS) .

Figures

FIGURES 7–12. Bidentogon expansus Shelley 7. Collum and first ring, dorsal view 8. Midbody ring, dorsal view. 9, Epiproct, dorsal view. 10. Gonopods in situ, ventral view. 11. Right leg 3, ventral view. 12. Part of right gonopod, ventral view.Abbreviations: ac, acropodite; f3, femur of third leg; pf, prefemorite; sm, solenomere; tz, terminal zone. SEM stub WS33-7.