Paschatherium dolloi, (TEILHARD DE CHARDIN, 1927)
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publication ID |
https://doi.org/ 10.1111/j.1096-3642.2011.00787.x |
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persistent identifier |
https://treatment.plazi.org/id/03DE8792-FF9C-6543-FF46-FD1EFA17F93E |
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Marcus |
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scientific name |
Paschatherium dolloi |
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PASCHATHERIUM DOLLOI ( TEILHARD DE CHARDIN, 1927) ( FIGS 6I View Figure 6 , 7B View Figure 7 , 8A, B, D View Figure 8 )
*vp 1927 Adapisorex Dolloi Teilhard de Chardin : pp. 7–11, figs 2–4, 5a, c–h, 6a–b, d, pl. 1, figs 5–22, 25–28, pl. 2, figs 1–13.
1927 Insectivore indéterminé; Teilhard de Chardin: p. 12, fig. 8a–d, pl. 2, figs 21–23 (DP 4 and DP 4).
1964 Paschatherium dolloi (Teilhard de Chardin) ; Russell, pp. 238–239, pl. 14, figs 1, 2.
vp 1964 Paschatherium ?; Russell: p. 240 (CRL-827).
vp 1964 Paschatherium petri Russell : p. 305 (CRL- 827).
p 1981 Paschatherium dolloi (Teilhard de Chardin) ; Denys & Russel [sic], pp. 37–44, pl. 1.
2006 Paschatherium dolloi (Teilhard de Chardin) ; López-Martínez, Smith, Peláez-Campomanes & Smith, pl. 1, figs 1–8.
Lectotype: R dentary fragment with P 3 –M 2 and part of ascending ramus, IRSNB.CtM1140, Tienen Formation, Dormaal [ Teilhard de Chardin, 1927: 9, fig. 4 (N.B. the M 3 is an addition, representing another specimen); pl. 2, fig. 4]. Lectotype selection is necessary because a second species of Paschatherium , Pa. yvettae , has been recognized at Dormaal ( López-Martínez et al., 2006). IRSNB.CtM1140 fits within the size range of Pa. dolloi as restricted by these authors and lacks the mesiobuccally curved premetacristid of Pa. yvettae .
Material: L dentary fragment with P 4 –M 3, MNHN.F.CRL-827; RM 1, MNHN.F.CR-5-Bn; both Cernay.
Age and distribution: Sables de Châlons-sur-Vesle supérieurs, late Thanetian, Late Palaeocene, Cernay, France; Tienen Formation, zone PE I, earliest Ypresian, Early Eocene, Dormaal, Belgium; Sables d’Erquelinnes, zone PE I, earliest Ypresian, Early Eocene, Erquelinnes, Belgium; Suffolk Pebble Beds, Zone PE I, earliest Ypresian, Early Eocene, Ferry Cliff, UK.
Emended diagnosis: Medium-sized Paschatherium , mean length of M 1 1.92 mm ( López-Martínez et al., 2006) ( Pa. russelli and Pa. levei are larger; Pa. yvettae , Pa. marianae , and Pa. plaziati are smaller). P 4 without postmetaconule crista (shared with Pa. yvettae and W. krumbiegeli ). M 1 pre-entocristid with concave edge (shared with Pa. yvettae and W. girardi ). M 1 paraconid sublingual in position (shared with Pa. yvettae and Pa. russelli ). Lacks the mesiobuccal curvature of the lower molar premetacristid that characterizes the otherwise morphologically similar Pa. yvettae . M 1–2 precingulid strong, extensive, shelf-like, bulging mesially (shared with Pa. yvettae ).
Description
The teeth in the dentary are fairly heavily worn, particularly M 1, and the P 4 is broken mesially. P 4 is 1.18 mm wide; M 1 is 1.95 mm long by 1.46 mm wide; M 2 is 2.00 mm long by 1.62 mm wide; and M 3 is 1.65 mm long by a minimum of 1.24 mm wide. The basic pattern is very similar to the lectotype from Dormaal. The paraconid is crestiform on all three molars, the cristid obliqua ascends the back of the trigonid a short distance and the M 3 is proportionately smaller compared to M 2 than in W. girardi ( Fig. 7B View Figure 7 ). The back of the P 4 trigonid is steep and the talonid is narrower than the trigonid.
The M 1 is 1.77 mm long by 2.18 mm wide. It has equal height paracone and metacone, a distinct precingulum, a confluent postcingulum–metacingulum and a weak postmetaconule crista that does not join the postcingulum–metacingulum ( Fig. 6I View Figure 6 ).
Discussion
The measurements of the teeth in the Cernay dentary show M 2 to be larger than M 1, typical of the species ( Fig. 7B View Figure 7 ; López-Martínez et al., 2006: table 2). They also show M 1, M 1, and M 2 to fit well within the size range of the Dormaal type assemblage, in the case of M 1 and M 2 close to the mean ( Fig. 8 View Figure 8 ). All the measurements lie outside those of the morphologically similar Pa. yvettae . Morphology and proportions are also different from similar-sized W. girardi ( Fig. 8 View Figure 8 , Table 2). This is therefore the oldest recorded occurrence of Pa. dolloi , clearly very rare before its earliest Eocene acme in northern Europe. The first occurrence of Pa. yvettae is earlier, the middle Thanetian of Spain ( Gheerbrant et al., 1997; Pujalte et al., 2006).
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