Teilhardimys musculus, (TEILHARD DE CHARDIN, 1927)

Hooker, Jerry J. & Russell, Donald E., 2012, Early Palaeogene Louisinidae (Macroscelidea, Mammalia), their relationships and north European diversity, Zoological Journal of the Linnean Society 164 (4), pp. 856-936 : 915-918

TEILHARDIMYS MUSCULUS ( TEILHARD DE CHARDIN, 1927) ( FIGS 27, 33E)

vp 1840 Insectivorous bat; Owen, p. 194, fig. 3a.

vp 1846 Cheiropterous (?) insectivore; Owen, p. 17, fig. 7a.

* v 1927 Microhyus musculus Teilhard de Chardin : p. 24, fig. 23, pl. 5, fig. 20.

v? 1999 Microhyus cf. musculus Teilhard de Chardin ; López-Martínez & Peláez-Campomanes, pp. 690– 691, fig. 3.8.

v. 2000 Teilhardimys musculus (Teilhard de Chardin) ; Kretzoi & Kretzoi, p. 401.

v. 2006 Microhyus musculus Teilhard de Chardin ; Tabuce, Antunes, Smith & Smith, pp. 39–41, fig. 2. v. 2006 Microhyus musculus? Teilhard de Chardin ; Tabuce, Antunes, Smith & Smith, pp. 39, 41, fig. 1B.

Holotype: Left M 1, IRSNB. M115 , Dormaal Sand Member , Tienen Formation , Dormaal, Brabant, Belgium.

New material, Suffolk Pebble Beds: LP 4, NHMUK.M29708; RM 1, NHMUK.M29678; LP 4, NHMUK.M29687; LM 2, IM.92; all Kyson.

RP 3, HZM.2.39393; two RP 4 s, NHMUK.M85488, M85489; two LM 1 s, NHMUK.M85483, M85493; three LM 2 s, NHMUK. M50378 , M85484, HZM.1.39090; RM 2, HZM.6.39351; two LDP 4 s, NHMUK. M50377 , HZM.3.39202; RDP 4, HZM.2.39098; RP 2, NHMUK. M85490; LP 3, NHMUK.M85491; three LP 4 s, NHMUK. M50379 , M85492, HZM.5.39351; two LM 2 s, NHMUK.M85485, M85486; RM 2, NHMUK.M34871; LM 3, NHMUK.M85487; RM 3, HZM.31.39381; RDP 4 talonid, NHMUK.M85494; all Ferry Cliff.

LM 1, NHMUK.M33478; Harwich.

Age and distribution: Tienen Formation, zone PE I, earliest Ypresian, Early Eocene, Dormaal, Belgium; Suffolk Pebble Beds, Zone PE I, earliest Ypresian, Early Eocene, Ferry Cliff, UK; Tremp Formation, latest Thanetian, latest Palaeocene, Tendruy, Spain.

Emended diagnosis: P 3 with: metacone much smaller than paracone (metacone lacking in Te. reisi ). P 4 with: large paraconule, lacking preparaconule crista; large metaconule connected to protocone by neoformed postprotocrista (lacking in Te. reisi ); hypocone absent (present in Te. reisi and Te. brisswalteri ). P 3–4 paraconule and preprotocrista isolated from mesial cingulum (joined by preparaconule crista in Te. reisi and Te. brisswalteri ). P 3–4 with ectoloph (shared with Te. reisi ). P 3–4 paracone tilted buccally (shared with Te. reisi ). Lower premolars blade-like, P 4 taller than long buccally, strongly exodaenodont, with no metaconid, but with hypoconid forming sole unbasined talonid cusp, somewhat smaller than the protoconid (small metaconid in Te. reisi , large metaconid and basined talonid in Te. brisswalteri ). Molars relatively highcrowned, leading to proximity of buccal and lingual cusps. M 1–2 with metaloph and no postprotocrista (shared with Te. reisi ), and weak paraconule and metaconule (stronger in Te. reisi and Te. brisswalteri ). M 1 metacone subequal with paracone and some individuals with weak entoflexus (shared with Te. reisi ). Lower molars with: ectostylid (shared with Thryptodon ); incipient protolophid and hypolophid (shared with Te. reisi ). Precingulid joins paracristid to form mesiobuccal stylid on M 1–2 in some individuals (shared with Te. brisswalteri ). Entoconulid weak on M 1 (shared with Thryptodon ).

Description

New tooth types have been described by Tabuce et al. (2006). This did not include P 3, P 4, M 2, or P 3. Material from the Suffolk Pebble Beds described here fill in the gaps and some variation in M 1, P 2, and P 4 is documented. For measurements, see Table 10 .

P 3: HZM.2.39393 is identified as P 3 as it is similar to P 4 (q.v.), but lacks a metaconule and the metacone is much smaller than the paracone (Fig. 27A). The protocone is also asymmetrically developed and the protocone lobe is waisted from the more buccal parts of the tooth. Its length is within the range of those of P 4, but its width is less. These differences are comparable with those between P 3 and P 4 of Te. reisi .

P 4: This tooth has a distinctive transversely elongate triangular shape and differs from Te. reisi in several ways (Fig. 27B). Three specimens show the hypocone to be completely absent. The mesial margin is gently concave. Both paraconule and metaconule are isolated conical cusps with no connection to the marginal cingula, unlike Te. reisi , which has a preparaconule crista linking to the paracingulum ( Tabuce et al., 2006). The paraconule and metaconule are, however, linked to the protocone by narrow crests. These crests, by comparison with P 4 of Te. brisswalteri (q.v.), appear to be neoformed and nonhomologous with pre- and postprotocristae. The latter instead are represented by crests that descend basally mesially and distally from the protocone tip to join the lingual ends of the pre- and postcingula, respectively. There is slight variation in the heights of the paracone and metacone, the latter always being the lower. There is also marked size variation as in Te. reisi .

·

Figure 27. Scanning electron micrographs of gold-palladium coated epoxy casts of teeth of Teilhardimys musculus ( Teilhard de Chardin, 1927) , Suffolk Pebble Beds, earliest Ypresian, UK. A, RP 3 (reversed), Ferry Cliff (HZM.2.39393). B, RP 4 (reversed), Ferry Cliff (NHMUK.M85488). C, LM 1, Ferry Cliff (NHMUK.M85493). D, LM 2, Ferry Cliff (NHMUK. M50378 ). E, LM 1, Ferry Cliff (NHMUK.M85483). F, LM 3, Ferry Cliff (NHMUK.M85487). G, RP 2 (reversed), Ferry Cliff (NHMUK.M85490). H, LP 3, Ferry Cliff (NHMUK.M85491). I, LP 4, Kyson (NHMUK.M29687). J, LM 2, Kyson (IM.92). Views are: buccal (A1, B1, C1, D1, G2, H2, I2, J2), occlusal (A2, B2, C2, D2, E, F, G1, H1), and lingual (G3, H3, I3, J3). Scale bar = 2 mm.

P 2: This is similar to P 3, but smaller and lower crowned (Fig. 27G). It is similar to that of Te. reisi , but flares more. It also flares more than a P 2 from Dormaal ( Tabuce et al., 2006: fig. 2e).

Discussion

This species was first noticed and figured by Owen (1840, 1846), but without naming it or recognizing its true affinities (see synonymy list). The specimen concerned, an M 2, is refigured here (Fig. 27J).