Nearctic, Pachyotominae

Palacios-Vargas, José G. & Arbea, Javier I., 2022, The subfamily Pachyotominae in Mexico (Collembola: Isotomidae) with description of a new Pachyotoma species, Zootaxa 5194 (2), pp. 245-259 : 258

Key to the Nearctic Pachyotominae with granulated integument

1. Furcula in the form of two mounds. Pigment, eyes and tenaculum absent................................................................................ Paranurophorus simplex Denis, 1929 (Holarctic, also known from Australia)

- Furcula usually not so reduced. Pigment, eyes and tenaculum present............................................ 2

2. Furcula reduced; mucro absent............................................................................... Coloburella octogenaria ( Mills & Schmidt, 1957) ( USA: Illinois, Tennessee; Canada: Vancouver I.; Mexico: Veracruz)

- Furcula varying in length; mucro usually separate from dens.................................................. 3

3. Dens without anterior setae..... Bonetrura boneti ( Yosii, 1962) (USA: Louisiana, West Virginia; Mexico: Puebla, Veracruz)

- Dens with anterior setae................................................................... 4 ( Pachyotoma )

4. 7 or less anterior setae on dens.......................................................................... 5

- 8 or more anterior setae on dens......................................................................... 9

5. 1 anterior seta on dens.................................... P. vernoga ( Wray, 1958) ( USA: North Carolina, Indiana)

- 4–7 anterior setae on dens.............................................................................. 6

6. Manubrium with 1+1 anterior setae.................................................................................................. P. muskegis ( Guthrie, 1903) ( USA: Minnesota; Canada: Ontario; Mexico: Jalisco; Panama)

- Manubrium without anterior setae........................................................................ 7

7. PAO shorter than nearest eye......................................... P. primamexicana sp. nov. ( Mexico: Puebla)

- PAO longer than nearest eye............................................................................ 8

8. Tibiotarsi I – III with 1,2,2 acuminate or slightly clavate tenent hairs...................................................................................... P. alpa ( Christiansen & Bellinger, 1980) ( USA: New Hampshire, Vermont)

- Tibiotarsi with 2–3 clavate tenent hairs............ P. vetusta ( Folsom, 1937) ( USA: California, New Mexico, Minnesota)

9. More than 40 anterior setae on the dens; manubrium with 2+2 anterior setae; furcula long, almost reaching VT............................................................................ P. crassicauda ( Tullberg, 1871) (Holarctic)

- No more than 10 anterior setae on the dens; manubrium without anterior setae; furcula shorter......................................................................... P. antiqua ( Folsom, 1937) ( USA: Missouri, Utah, West Virginia)