A new species of the genus Diplocentrus Peters, 1861 (Scorpiones, Diplocentridae) from Oaxaca, Mexico

Abstract A new species of the genus Diplocentrus Peters, 1861 is described, based on several specimens collected in the Mexican state of Oaxaca. It is characterized by a high telotarsal spiniform setae count (4-5/5:5/6:6/6:6/6-7), and the pectinal tooth counts of 12–15, mode = 13 (male) or 11–13, mode = 12 (female). With the description of this species, the diversity of the genus is increased to 51 species in Mexico.


Introduction
The genus Diplocentrus Peters, 1861 comprises nearly 60 species, 51 of them are distributed in Mexico, is the most diverse genus in the family Diplocentridae Karsch, 1880(Santibáñez-López et al. 2013a). The Mexican species were divided in two groups by Hoffmann (1931), based on size and coloration. Francke (1977) redefined the groups in a key to identification of the Diplocentrus species occur-ring in the Mexican state of Oaxaca, based on cheliceral and pedipalp femur ratios, and renamed the whitei group to mexicanus group because it included type species (Diplocentrus mexicanus Peters, 1861). Nevertheless, Francke (1978) realized that the distinction of both groups was problematic because the diagnostic characters of the pedipalp femur were also used to separate other genera in the family. Recently, Santibáñez-López et al. (2013a) presented an operational diagnosis for the keyserlingii group; but did not assume that it was monophyletic, pending further investigation of Diplocentrus phylogeny. Fifteen species are reported for the Mexican state of Oaxaca, nine of them belong to the keyserlingii group, and six to the mexicanus group. In the present contribution, Diplocentrus franckei, sp. n. from the mexicanus group is described from Oaxaca, Mexico; it is compared to its most morphological similar species.
Pedipalp surfaces in D. melici are punctuate, and minutely granular or smooth in D. franckei. Carapace anteromargin notch U-shaped in D. franckei, while in D. melici is V-shaped. Pedipalp patella dorsoexternal and externomedian carinae are strongly developed in D. franckei (male), but both are obsolete in D. melici (male).
Adults of D. franckei (55-60 mm) are smaller than adults of D. jaca (75-90 mm). Metasomal segment V ventral carinae are strongly serrate in D. jaca, while in D. franckei are granular. Carapace anteromargin notch is strongly deep (reaching the second pair of lateral ocelli level) in D. jaca, while it is moderately deep (reaching the first pair of lateral ocelli level) in D. franckei. Pedipalp chela is slender in D. jaca (male, chela length:ratio= 4.97), and rounded in D. franckei (male, chela length:ratio= 2.32).
Etymology. This species is dedicated to Dr. Oscar Francke, for his enormous contribution to the taxonomy and systematics of the genus Diplocentrus, and his guidance through the years in my education.
Distribution. Diplocentrus franckei, sp. n. is known from the Villa Alta district within the Northern mountain range in Oaxaca; in the municipalities of San Andres Yaa, San Andres Zoolaga, San Juan Tabaa, San Melchor Betaza (Fig. 6).
Ecology. This species was observed first on the soil surface, walking at night with UV detection; later it was collected inside houses, under stones and also in the crevices of rock walls. It was also found doorkeeping at burrow entrances in walls of road cuts. The burrows were constructed at an angle of ca. 30° to the wall, ca. 40-50 cm long and mostly straight with some turns around stones in the soil matrix. The dominant vegetation was the transition between dry tropical forest and pine-oak forest at 1500 m. Centruroides serrano Santibáñez-López & Ponce-Saavedra, 2009 was collected in sympatry. The habitat and habitus of D. franckei, sp. n. are consistent with the pelophilous ecomorphotype (Prendini 2001).