Parochodaeus Nikolajev, 1995: 77

Paulsen, M. J. & Ocampo, Federico C., 2012, The Ochodaeidae of Argentina (Coleoptera, Scarabaeoidea), ZooKeys 174, pp. 7-30 : 11

Parochodaeus Nikolajev, 1995: 77

Type Species.

Parochodaeus pectoralis (LeConte, 1868), by original designation.

Diagnosis.

This genus contains species with an elytral locking mechanism consisting of a bituberculate margin on the propygidium and dentate elytral apices.

Description.

Ochodaeidae : Ochodaeinae . Form convex, ovate. Length: 2.6-9.1 mm. Width: 1.5-4.9 mm. Surface/Color: Dorsal surface of head, pronotum, and elytra setose; setae varying from short bristles to longer setae; setae erect or subdepressed. Color testaceous to dark castaneous, variable within species. Head: Clypeus varying from semicircular to subtrapezoidal, often sexually dimorphic in length (longer in females). Frontoclypeal suture indistinct but generally discernible. Frons simple or variably armed with tubercles, horns, or carinae. Mentum variable between species. Mandibles moderately large, externally rounded to angulate, visible beyond labrum in dorsal view. Labrum strongly projecting between mandibles, setose. Antenna with 10 antennomeres; 3- antennomere club nearly round, pubescent. Pronotum: Surface densely punctate, punctures fine to moderate, each with or without a distinct setigerous tubercle anteriorly; setae moderately long. Elytra: Striae (except sutural) not impressed, uniserially punctate; punctures moderate to large, moderately deep, round, lacking setae. Intervals tuberculate; tubercles fine to moderate, forming irregular rows, setigerous; setae variable in length. Legs: Protibia with 3 external teeth increasing in size distally; occasionally with apical internal tooth or “thumb” produced beyond tarsal insertion. Metafemur usually simple with slightly produced rounded lobe, occasionally armed with 1 large tooth or several small, irregular teeth on dorsal or ventral posterior margin before apex. Metatibia form variable from slender and subcylindrical to broad and flattened. Abdomen: Stridulatory peg, if present, near anterolateral angle of propygidium (necessary to unlock elytron and depress abdomen to view). Propygidial margin with 2 tubercles on posterior margin.

Composition.

The genus Parochodaeus currentlyconsists of 17 species known from the central Great Plains of the United States south to Río Negro Province in Argentina ( Paulsen 2007; Paulsen 2011). An additional seven species from Argentina are described in this paper, bringing the total number of species in the genus to 24.

Remarks.

The presence or absence of a stridulatory peg on the abdomen and the form of the mentum are extremely useful in determining species. The head armature of frontal horns, tubercles, and carinae are allometric, and, as such, extremely small specimens will still have the appropriate structure, albeit extremely reduced. In such cases, for example with exceptionally small Parochodaeus campsognathus (Arrow), the other characters given should be used to confirm identification.

Key to the Parochodaeus species of Argentina