Pachyotoma Bagnall, 1949

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 : 246-247

Genus Pachyotoma Bagnall, 1949

Pachyotoma (sensu Deharveng 1979; Potapov 2001; Potapov et al. 2005), has pigmentation very dark, no pattern. Strong secondary granulation on the body and subcuticular reticulation. Third abdominal segment equal to IV. Maxillary palps bifurcate, 3–4 sublobal hairs. Labium with a complete set of guards (16), 5 basomedian and 3 proximal setae. Empodium present. Tibiotarsi with 7 setae in the distal ring, often in a subdistal segment. Ventral tube only with lateral and posterior setae. Manubrium without or with only a few tiny anterior setae on distal third, but posterior setae can be very numerous. Dens usually not well developed, thick, cylindrical, or conical, with a granulated posterior side, never crenulate. Mucro separated from dens, massive and lamellate. With three parts of furcal subcoxae (anteriolateral, anteriomedial and posterior). Retinaculum with rami quadridentate and 1 to 4 or more setae dorsally on corpus. Anal spines absent. Setae short, macrosetae undeveloped. Body sensilla mainly in front of the p-row of setae, varies from very abundant to moderately abundant. Apomorphic character: secondary cuticular granulation. Plesiomorphic characters: abundant sensillar chaetotaxy, weak differentiation of macrosetae and primitive dens.

Genotype: Isotoma crassicauda Tullberg, 1871: 152 .