Petrosaltator Rathbun and Dumbacher

Dumbacher, John P., Carlen, Elizabeth J. & Rathbun, Galen B., 2016, Petrosaltator gen. nov., a new genus replacement for the North African sengi Elephantulus rozeti (Macroscelidea; Macroscelididae), Zootaxa 4136 (3), pp. 567-579 : 574

Petrosaltator Rathbun and Dumbacher , new genus

Fig. 3

Type species: Petrosaltator rozeti ( Duvernoy, 1833)

Holotype. The type specimen is located at Musée Zoologique de la ville de Strasbourg, France; specimen number MZSMAM03685.

Geographic distribution. Petrosaltator has a unique range, and is currently the only species of the family Macroscelididae that occurs north of the Sahara Desert. It is known from the Maghreb Region of northern Africa, in Mediterranean, sub-desert, and montane zones from near sea level to 2725m elevation ( Fig. 1 ) ( Corbet & Hanks 1968; Cuzin & Séguignes 1990).

Diagnosis and description. The genus Petrosaltator is monotypic ( P. rozeti ) ( Corbet & Hanks 1968; Duvernoy 1833; Perrin & Rathbun 2013). Features that distinguish the genus from all other Macroscelidinae are rare (see below), thus explaining why it was included in Elephantulus by earlier workers. Genetic data are among the most useful diagnostic characters, and have been used here and elsewhere to identify P. rozeti and clearly align it with Petrodromus and Macroscelides ( Douady et al. 2003; Kuntner et al. 2011; Smit et al. 2011).

Petrosaltator measurements include head and body 90–130mm, tail 95–140mm, hind foot 29–37mm, upper tooth row 16–19mm, with larger individuals from north of the Atlas mountains belonging to the nominate forms, P. r. rozeti , and smaller individuals south of the Atlas mountains belonging to P. r. deserti ( Corbet & Hanks 1968).

Despite overall morphological similarity, Petrosaltator differs from Elephantulus in the following characters. In penis morphology, Petrosaltator has two lateral lobes and a tapering distal end, whereas Elephantulus species have a bulbous tip of the glans penis ( Woodall 1995b). In superficial male mammary morphology, Petrosaltator males have small nipples which are absent in Elephantulus ( Olbricht & Stanley 2009) . Finally, Petrosaltator has an ossified stapediofacial tube that corresponds to the bony enclosure of the path of the facial nerve within the bulla ( Benoit et al. 2013).

Corbet & Hanks (1968) additionally identify three morphological characters that distinguish Petrosaltator from Elephantulus (see Corbet & Hanks 1968, Table 1 , page 49). Character states shared by Petrosaltator and Macroscelides include a large tragus and highly rugose interdigital pads ( Corbet & Hanks 1968). Synapomorphies of Petrosaltator and Petrodromus include the double root on the third upper incisor (I3). Corbet & Hanks (1968, Table 1 ) identify no single morphological character that has a unique character state in Petrosaltator rozeti ( Corbet & Hanks 1968) .

Petrosaltator can additionally be distinguished from Macroscelides in having significantly smaller mastoids and auditory bullae, smaller supratragus, and slightly less-silky pelage ( Corbet & Hanks 1968). Petrosaltator differs from Petrodromus in being smaller overall, having the hallux present, having three rows of mammae (vs. two in Petrodromus ), and having no facial markings (vs. Petrodromus having a prominent dark spot behind the eye), having caudal hair on distal dorsal tail surface (dorsal tail surface is essentially naked in Petrodromus ), and the eye and pinnae are proportionally smaller in Petrosaltator in comparison to overall head size,

Etymology. The roots of Petrosaltator (masculine gender) are Greek (petro) and Latin (saltator), together meaning “rockdancer”. This genus name reflects the habitats occupied by this species, which are dominated by rocks and boulders ( Séguignes 1988). Petrosaltator also alludes to the phylogenetic relationship with Petrodromus (meaning rockrunner with Greek roots), although oddly Petrodromus tetradactylus is not specifically a petrophile ( Jennings & Rathbun 2001). We suggest that the common name of Petrosaltator rozeti continue to be the North African Sengi or Elephant-shrew.

Specimens examined. Our work is based primarily on molecular analyses, and specimens sequenced are listed in Table 1 . The two P. rozeti specimens sequenced were P. rozeti rozeti (CASMAM27982 from north of the Atlas Mountains) and P. r. deserti [from Douady et al. (Douady et al. 2003), south of the Atlas Mountains]. Based on the divergence level between these two specimens ( Fig. 2 , uncorrected p-distance at 12s–16s rDNA = 1.09% divergence), recognizing two subspecies of P. rozeti could be justified, although the lack of morphometrics, our minimal sample size, and analysis of only one genetic region precludes any definitive determination.

Figures

FIGURE 1. North African sengi distribution (shaded area) in the Maghreb region of northern Africa. Distribution based on minimum convex polygon of 203 points with perimeter modified subjectively to avoid unsuitable habitat (Rathbun 2015). Star symbol is approximate location of type specimen, x symbol is approximate location of Douady (2001) voucher specimen, and + symbol is the location of California Academy of Sciences voucher specimen (see Methods and Table 1).

FIGURE 2. Molecular phylogeny of E. rozeti and related taxa showing the proposed delimitation of the subfamily Macroscelidinae into two tribes. Branch support is shown as Bayesian posterior probabilities / parsimony bootstrap values / maximum likelihood bootstrap values. Nodes with best possible support (1 / 100 / 100) are denoted with an asterisk. Scale bar represents corrected (GTR + G + I) distances.

FIGURE 3. Images of the three genera of the tribe Macroscelidini. A. Basking North African sengi (Petrosaltator rozeti). Adult male near Salas village, Jhilet Mountains, Marrakesh, Morocco on 18 July 2005, specimen number CAS MAM 27982. Photo G. Rathbun. B. The four-toed sengi (Petrodromus tetradactylus), Mareja Community Reserve, Pemba, northern Mozambique, 17 June 2011, specimen number CAS MAM 29347, Photo G. Rathbun. C. The Namib round-eared sengi (Macroscelides flavicaudatus), south of the Micberg formation, Kunene Region, Khorixas District, 7 May 2010, specimen number CAS MAM 29700, photo J. P. Dumbacher.