Condylura sp.

Sansalone, G, Kotsakis, T & Piras, P, 2016, Condylura (Mammalia, Talpidae) reloaded: New insights about the fossil representatives of the genus, Palaeontologia Electronica 19 (3), pp. 1-16 : 4-8

Condylura sp.

1963 Condylura sp. ; Lychev, p. 13, figs 1A, 1a.

1997 Condylura sp. ; McKenna and Bell, p.282.

2008 Condylura sp. ; Gunnel, Bown, Hutchinson,

and Bloch, p. 103.

Material

Sample. 1 left humeral fragment

Locality. Kalkaman Lake, Kazakhstan

Age. mammal age equivalent MN 8; 11.9- 11.1 m.y.a.

Horizon. Early Sarmatian or Late Astaracian mammal age equivalent ( MN 8; 11.9- 11.1 m.y.a.).

Description

Humeral fragment ( Figure 3.1-2 ). Maximal width of distal region: 8.5 mm; width of the humeral shaft: 3.6 mm. The proximal part is lost and the humeral head is not preserved. The capitulum is also broken. The fossa for flexor digitorum profundus is round and deep. The supracondylar foramen is wide and triangular in shape. The humerus shows a torsion of the shaft as occurs in fossorial moles. The distal part of the pectoral crest is slightly pronounced. Enlarged distal region of the humerus with the medial edge of the trochlea placed in the middle of the trochlear area. The greater sulcus is wide.

New Diagnostic Feature

Position of the medial edge of the trochlea and humeral shaft width. The medial edge of the trochlea is positioned in the middle of the trochlea in the shrew-moles ( Urotrichini , Neurotrichini and Scaptonyx ) while all highly fossorial moles ( Talpini and Scalopini ) have it medially displaced. Nevertheless, the humeral shaft of the highly fossorial talpids is more robust than that of the shrew-moles.

This genus-diagnostic character was detected among humeral material from both shrew-moles and true-moles ( Hutchinson, 1968; Hutchinson, 1974; Ziegler, 2003; Sánchez-Villagra et al., 2004; Piras et al., 2012; Piras et al., 2015; Schwerman and Thompson, 2015; Sansalone et al., 2016).

Comparisons

We excluded from the comparisons all the robust highly fossorial moles (i.e., Talpini and the more robust Scalopini ) due to the evident difference in the overall robustness of the humeral shaft. Furthermore, the Kazakh specimen is more robust than all the shrew-moles ( Urotrichini and Neurotrichini ); therefore we did not include these taxa in the comparisons. We compared the mole from Kalkaman Lake with all the Neogene less robust Scalopini and with the other described Condylura species.

cf. Condylura sp. The specimen from Kalkaman Lake differs from the cf. Condylura sp. from Hemphillian of Oregon ( Hutchinson, 1984) in having a reduced minor sulcus. The two specimens are identical in the humeral distal region morphology. They share the triangular supracondylar fora-

3 5 1 2

6 7 8

2

men and the central position of the trochlear medial edge ( Figure 3.3-5 ).

Condylura kowalskii Skoczeń, 1976 . The Kazakh specimen is very similar to the Polish species in the overall shape of the humeral shaft ( Figures 3.6-7, 4.1 ). It is almost identical in the trochlear morphology sharing the central position of trochlear medial edge. However, C. kowalskii possesses a minor sulcus wider than the Kazakh condylurine mole ( Skoczeń, 1976; Rzebik-Kowalska, 2014).

Condylura izabellae Skoczeń, 1976 . The Kazakh specimen differs from the Polish smaller Condylura ( Skoczeń, 1976; Rzebik-Kowalska, 2014) for the same features of C. kowalskii .

1 2 3

Yanshuella primaeva Yunoscaptor scalprum Scapanulus oweni

4 5 6

Wilsonius ripafodiator Leptoscaptor robustior Leptoscaptor bavaricum

Condylura cristata Illiger, 1811 . The specimen from Kalkaman closely resembles C. cristata in the width of both sulci ( Hutchinson, 1984). The distal part of the pectoral crest is slightly pronounced, as in C. cristata . The similarities in the trochlea are even more striking, both taxa share the medial edge positioned in the middle of the trochlea. However, the Kazakh specimen possesses the spine of the medial edge of the trochlea medially bended while it is straight in C. cristata ( Figures 3.8 , 4.2 ).

Yanshuella primaeava Storch and Qiu, 1983 . Condylura sp. possesses a wider greater sulcus and a wider minor sulcus. Further, the distal end of the pectoral crest is less pronounced. Finally, in Yanshuella , the medial edge of the trochlea is medially displaced (as in all other highly fossorial talpids; Storch and Qiu. 1983), while in Condylura sp. is placed in the middle of the trochlea ( Figure 5.1 ).

Yunoscaptor scalprum Storch and Qiu, 1991 . The same considerations made for the comparison with Yanshuella hold for Yunoscaptor ( Storch and Qiu, 1991) . They differ for the trochlea medial edge and, further, for the shape of the supratrochlear fossa (frontal view) ( Figure 5.2 ).

Scapanulus oweni Thomas, 1912 . The differences in the width of both minor and greater sulci are less evident, though S. oweni possesses the medially displaced medial edge of the trochlea ( Figure 5.3 ). The last evidence leaves no doubt in excluding close relationships with Scapanulus ( Hutchinson, 1968; Storch and Qiu, 1983).

Wilsonius ripafodiator Hutchinson, 1968 . The two taxa are almost indistinguishable for the width of both sulci, evidencing the plesiomorphic state of these characters ( Hutchinson, 1968). However, the shape of the trochlea is, again, highly different. The Kazakh specimen clearly shows the plesiomorphic features of the humeral distal region, while Mioscalops , possessing the medially displaced medial edge of the trochlea, shows apomorphic characters that reflect a better adaptation to digging ( Hutchinson, 1968) ( Figure 5.4 ).

Leptoscaptor robustior Ziegler, 2003 . Condylura sp. clearly differs from L. robustior in the width of the humeral shaft. In L. robustior the minor and greater sulci are narrower, and the medial edge of trochlea is medially displaced as in other highly fossorial moles ( Ziegler, 2003) ( Figure 5.5 ).

Leptoscaptor bavaricum Ziegler, 2003 . Condylura sp. resembles L. bavaricum in the overall slenderness of the humeral shaft and in the width of minor and greater sulci. On the other hand, L. bavaricum shows an elliptic supracondylar foramen and the medial edge of the trochlea medially displaced ( Ziegler, 2003) ( Figure 5.6 ). These features clearly separate the two taxa.

Remarks

The humeral fragment from Kalkaman Lake shows close affinities with the other condylurine moles. In particular, the morphology of the trochlear area appears to be distinctive for the genus Condylura . This feature unambiguously separates Condylura from all highly fossorial moles. However, Urotrichini , Neurotrichini and Scaptonyx also show a trochlear medial edge placed in the middle of the trochlea ( Hutchinson, 1968; Sánchez-Villagra et al., 2004; Schwerman and Thompson, 2015; Sansalone et al., in press). Despite this evidence, the more robust and wide humeral shaft leaves no doubt about the attribution of the Kazakh specimen to the genus Condylura . Unfortunately, the poor conditions of the proximal region of the humerus do not allow any specific attribution.

Figures

FIGURE 3. Drawings (1-5, 8) and photographs (6 and 7) showing fossil and extant representatives of genus Condylura. 1 and 2, Condylura sp., left humerus in caudal (1) and frontal (2) views, modified from Lychev (1963). 3-5, cf. Condylura sp., right humerus (YPM 20699, YPM) in caudal (3) and lateral (4) views and close-up of the greater tuberosity in medial view (5), modified from Hutchinson (1984, figure 1B). 6 and 7, Condylura kowalskii, left humerus (MF/ 1006/16, ISEZ-PAN) in frontal (6) and caudal (7) views, modified from Rzebik-Kowalska (2014, figure 2.1, 2.2). 8, Condylura cristata, right humerus in caudal view, modified from Hutchinson (1984, figure 1A). Scale bars represent 1 mm.

FIGURE 4. 1, Condylura kowalskii, mandible fragment bearing p1 and p2 in lingual view (MF/1006/4, ISEZ-PAN); from Rzebik-Kowalska (2014, figure 1.3). 2, Line drawing of a left mandible of Condylura cristata in labial view, modified from Laerm et al. (2007).

FIGURE 5. Drawings (1-4) and photographs (5-6) of talpid species humeri in caudal view. 1, Yanshuella primaeva, left humerus (IVPP-6455, IVPP), from Storch and Qiu (1983, figure 39b). 2, Yunoscaptor scalprum, left humerus (IVPP-V- 9741.38, IVPP), from Storch and Qiu (1991, figure 48b). 3, Scapanulus oweni, left humerus, from Hutchinson (1968). 4, Wilsonius ripafodiator, left humerus (UO-22366, UO), from Hutchinson (1968, figure 55). 5, Leptoscaptor robustior, right humerus (P35-58.6, NHMA), from Ziegler (2003, figure 3B2). 6, Leptoscaptor bavaricum, left humerus (P10- 610.2, NHMA), from Ziegler (2003, figure 2I).

FIGURE 6. 1, Talpidae phylogeny resulting from a parsimony analysis based on 157 discrete morphological characters, modified from Sánchez-Villagra et al. (2006, figure 1). 2, Unconstrained Talpidae phylogeny based on a parsimony analysis (DELTRAN optimization) based on 176 discrete morphological characters, modified from Schwermann and Thompson (2015, figure 16A).

FIGURE 7. Map showing Condylura fossil bearing localities and a possible palaeobiogeographical scenario. The orange striped area represents the present distribution of the extant C. cristata. The orange star represents Condylura sp. (middle Miocene locality of Kalkaman Lake, Kazakhstan). The red square represents cf. Condylura sp. (late Miocene locality of Malheur River, Oregon, USA). The green triangles represent C. kowalskii and C. izabellae (Pliocene Polish localities). The blue circles represent the late Pleistocene-Holocene localities of C. cristata.