Talpa streetorum Lay 1965

Talpa streetorum Lay, 1965

Talpa streeti Lay, 1965 incorrect original spelling.

Type locality: Iran, Kurdistan Province, Hezar Darreh, 35°25ʹN, 47°07ʹE, 2180 m (Fig. 1, Table 1).

Material examined: We examined the dry-preserved skulls of five specimens from the type series, housed in the Field Museum of Natural History, Chicago, with specimen numbers 96421-96425. Of these, the holotype is 96424. In addition, we examined a further dry-preserved skull of T. streetorum from Divandarreh in Iranian Kurdistan, close to the type locality, labelled 111007. Our study is restricted to skull characters, as skins and other body parts were preserved in alcohol and so are unlikely to retain their original coloration and dimensions well. Collection of topotypical specimens in the future would allow these features to be better documented, as they are also missing from the original description (Lay 1965).

Measurements of holotype

Condylobasal length of skull 32.51 mm, maxillary tooth row 14.33 mm, breadth of braincase 16.42 mm, height of braincase 10.13 mm, breadth of rostrum over canines 5.07 mm, breadth of rostrum over molars 10.53 mm (Supporting Information, Table S3).

Measurements of paratypes

Means ± standard deviation (minimum–maximum). Linear measurements are in mm. Sample size = 4 for all measurements. Condylobasal length of skull 32.20 ± 0.600 (31.55–32.96), maxillary tooth row 14.23 ± 0.160 (14.08–14.44), breadth of braincase 16.75 ± 0.180 (16.59–17.00), height of braincase 9.76 ± 0.320 (9.34–10.01), breadth of rostrum over canines 5.00 ± 0.140 (4.79–5.10), breadth of rostrum over molars 10.64 ± 0.230 (10.44–10.97) (Supporting Information, Table S3, for measurements including additional FMNH specimen 111007).

Diagnosis

Very large mole; skull large with a stout, broad, rostrum, closest in overall appearance to T. hakkariensis sp. nov. (compare Figs 7 and 10). Upper premolars 1–3 and lower premolars 2–3 peglike, and 1st upper molar with at most trace of parastyle cusp, as in T. hakkariensis sp. nov. (see Fig. 11). Differs from T. hakkariensis sp. nov. in having multiple mandibular foramina and a broader base to the coronoid process (Fig. 13D). Our measurements show that condylobasal length and breadth of the anterior rostrum are about the same in the two species (T. hakkariensis sp. nov. means 32.88 mm and 5.24 mm; T. streetorum means 32.51 mm and 5.07 mm, respectively), but T. streetorum is larger in terms of palatal and braincase widths (T. hakkariensis sp. nov. means 9.86 mm and 16.30 mm; T. streetorum means 10.70 mm and 16.88 mm, respectively). The skull as a whole as measured by centroid size is larger in T. streetorum than in T. hakkariensis sp. nov., as is the mandible (Supporting Information, Fig. S2).

Comment

Note that the correct name for this taxon is T. streetorum, as corrected by Lay (1967), because it was named asser William S. and Janice K. Street, the genitive singular being used in error in the original description. Talpa streetorum was used by a number of workers (e.g. Niethammer 1969, Ziegler 1971), but appears to have been dropped since Corbet (1978) considered it an unjustified emendation. Following Article 31.1.2 of the Code, however, the correct name is clearly T. streetorum. Despite the lack of genetic data, our morphometric analyses show that T. streetorum differs significantly from T. hakkariensis sp. nov. and T. davidiana s.l. on skull characters. On this basis, we reinstate T. streetorum as a valid species, apparently endemic to Iran. Further work in the future, including DNA sequence data, would be useful to confirm this hypothesis. It was not possible to obtain tissues for molecular analyses due to restrictions outside our control.