Geotrupes (Onthotrupes) viridiobscurus Jekel, 1865

Kohlmann, Bert, Arriaga-Jimenez, Alfonsina & Roes, Matthias, 2018, Dung beetle vicariant speciation in the mountains of Oaxaca, Mexico, with a description of a new species of Phanaeus (Coleoptera, Geotrupidae, Scarabaeidae), ZooKeys 743, pp. 67-93 : 81-83

Geotrupes (Onthotrupes) viridiobscurus Jekel, 1865 Figs 6, 9c, 10a

Geotrupes viridiobscurus : Jekel (1865: 599), Bates (1887: 113), Howden (1964: 50, 52-53, 87), Howden (2003: 97), Martínez and Suárez (2006: 778), Trotta-Moreu et al. (2008: 43, 47, 50, 51), Trotta-Moreu & Lobo (2010: 46), Alvarado et al. (2013: Supplemental material).

Geotrupes saundersi : Jekel (1865: 568), Bates (1887: 113).

Geotrupes felschei : Nonfried (1894: 114).

Material.

Mexico. Oaxaca. Zempoaltéptl, 27-V-17, coprotrampa, 17°7'5"N, 96°0'W, matorral/pastizal, 3040 m Arriaga A. and Arenas A. Col.; 30-V-17, bosque de pino/aile 3190m; 17°9'7"N, 96°1'29"W, bosque de encino 2850 m. Reserva Comunitaria San Pablo, Etla, 20-IX-16 coprotrampa, 17°16'70"N, 96°68'55"W, bosque de pino 2980 m; 17°16'72"N, 96°68'50"W, 2980 m; 17°17'14"N, 96°67'26"W, 3070 m; 17°17'70"N, 96°67'27"W, 3110 m; 17°17'12"N, 96°67'20"W, bosque de pino 3100; 23-IX-16, 17°17'84"N, 96°70'38"W, bosque pino/encino 2700 m. Yucuiji, San Esteban Atatlahuca, 18-08-17, exc. caballo, 17°07'32"N, 97°40'44"W, bosque de pino 3150 m. La Chinantla, 17°35'48"N, 96°28'20"W, 2200 m; 17°35'12"N, 96°29'21"W, 2400 m; 17°34'48"N, 96°29'43"W, 2600 m. El Llano de las Flores, 17°45'N, 96°50'W, 2800 m.

Historical.

Oaxaca. Duraznal, 17°1'55"N, 96°10'12"W, 1820 m.

Notes.

So far, this species has only been collected in Oaxaca and seems to be restricted to the Sierra Norte (Sierra de Ixtlán, Sierra Mazateca, and Nudo del Zempoaltépetl) in the northern part of the state. Howden (1964) cites only two historical localities for the state taken from Bates’ (1886-1890) work, Duraznal, Oaxaca, and (La) Parada. The latter we have been unable to locate. Martínez and Suárez (2006) subsequently cited the locality of "El Llano de las Flores" for this species. Trotta-Moreu et al. (2008) published a study on the known and potential distribution of Geotrupidae in Mexico. Using the GEOMEX database, they predicted a potential distribution based on six localities (which are not cited in their text) and calculate mean values of temperature (15.4 ± 3 °C), precipitation (1357 ± 936 mm) and altitude (1793 m), as well as a potential distribution area (3352 km2) for this species in the state of Oaxaca. They ambiguously cite that this species is distributed in the Sierra Madre del Sur, not specifying that actually it is distributed in the Sierra Norte. A recent book on the biodiversity of the Sierra Madre del Sur by Luna-Vega et al. (2016) implies that all mountains in Oaxaca belong to the same biogeographic region called Sierra Madre del Sur. This is not a correct biogeographic regionalisation, as the results of this present paper and another ( Kohlmann in press) show great differences in the dung beetle fauna of the Sierra Norte and the Sierra Sur. The Sierra Norte shows considerable influence from elements stemming from the Sierra Madre Oriental and the Trans Mexican Volcanic Belt ( Kohlmann in press). Finally, Alvarado et al. (2013) cite three georeferenced localities at La Chinantla. With the present collecting localities, we can recalculate and correct the Trotta-Moreu et al. (2008) too low mean value for altitude for this species.

Taxonomic relationships.

Geotrupes pecki and G. viridiobscurus have very similar aedeagi with only small differences on the parameres, as can be observed from the photographs of their genitalia (Fig. 10). They also present small differences in the elytral striae, being more or less punctate or crenulated as well as having a more or less punctate pronotum, over the whole surface ( pecki ) or concentrated at the pronotal sides ( viridiobscurus ). Howden (1974) has indicated that G. pecki has a heavily punctate pronotum, but as Fig. 9 clearly shows, this is not always the case and the pronotum can resemble the one of G. viridiobscurus . Due to the significant taxonomic similarity discussed above it is here postulated that this species pair are sister species.

Chorological affinities.

The known distribution of G. viridiobscurus in the Sierra Norte is relatively adjacent to its closest taxonomic relative, G. pecki , in the Sierra Sur, only 125 km away in a straight line (Fig. 6). Both species are distributed in pine and pine-oak forests; G. viridiobscurus also has been collected in oak and pine/alder forest. G. pecki has been collected from 2400 m to 3000 m altitude whereas G. viridiobscurus has been collected from 2000 m to 3200 m altitude (the Duraznal historical record with 1800 m altitude does not represent a precise locality). The Trotta-Moreu et al. (2008) mean altitude calculations of 1800 m for both species may be incorrect, and therefore it is probable that their calculations of the other climatic variables (temperature and precipitation), and distribution predictions, also would be erroneous.