Prolouisina atavella Hooker & Russell 2012
Creators: name: Hooker, Jerry J.
name: Russell, Donald E.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Macroscelidea
Louisinidae
Prolouisina
Prolouisina atavella

description: PROLOUISINA ATAVELLA (RUSSELL, 1964)   COMB. NOV. (FIGS 21, 33A)   
 *v 1964 Louisina atavella Russell: pp. 245–247, pl. 15, figs 4–6.   
 Holotype: R dentary with P 4 –M 3 and alveoli for P 2–3, MLU.Wa/356, Walbeck.   
 Paratypes: See list of referred material, Walbeck (Russell, 1964: 245).   
 New material: Composite upper dentition (LP 4 –M 2, two RP 4, RM 1–3), MLU.Wa/418; composite lower dentition (LP 4, two LM 3, RP 3, P 4, M 3), MLU.Wa/419; L dentary with P 4 –M 3, MLU.Wa103.2011; all Walbeck.   
 Age and distribution: Known only from the late Selandian, Middle Palaeocene fissure fillings of Walbeck, Germany.   
 Diagnosis: As for genus, monotypic.   
 Description   
  P 4:  The five teeth show an outline subdivided into a larger buccal and a smaller lingual lobe, with a ‘waist’ in between (Fig. 21A 2, B2). The paracone is larger than the metacone (Fig. 21A 1, B1). There is a trigon basin but without intermediate conules and the postprotocrista ends at the foot of the metacone. There is a distal cingulum with a small hypocone at its lingual end. In four of the five specimens, there is no contact between the postprotocrista and the hypocone and, like Louisina, there is no preparacrista. The remaining specimen has a crest linking the postprotocrista to the hypocone, as in L. marci and Te. brisswalteri, and a preparacrista as in the latter (Fig. 21A 2).   
  M 1–2:  These teeth are very similar in structure to those of L. marci and Te. brisswalteri (q.v.), but they are less exodaenodont and the parastyle is lower; there is a protostyle at the lingual end of the mesial cingulum of M 1, but not of M 2 (Fig. 21B). There may be a large metastyle on M 1 (Fig. 21B 2).   
  M 3:  This tooth is also very similar to those of L. marci and Te. brisswalteri, but relatively shorter (Fig. 21B).   
  P 3:  The single specimen is simple with a short distal crest from the protoconid representing the metaconid and a single cusped transversely elongate, scarcely basined talonid (Fig. 21D). It is similar to most L. marci, but less exodaenodont and with a lower paraconid.   
  P 4:  The pattern of similarity to L. marci is repeated here but less exodaenodont and with a distinct but tiny paraconid, which is lower on the crown (Fig. 21C, E). The metaconid is consistently present and smaller than the protoconid. The talonid bears a hypoconid and is basined and variable in length.   
 Lower molars: These teeth are very similar in morphology to those of Te. brisswalteri and L. marci (q.v.) and in size to the former. They appear slightly less exodaenodont, but the difference is subtle. The main difference from Louisina is the small but distinctly cuspate paraconid, which is most obvious on the nearly unworn composite dentition MLU.Wa/415 (Fig. 21E). The paraconid is indistinct in Louisina. There is also a slightly stronger precingulid (Fig. 21C, E 1, E 2), which is almost missing in the other two genera. There is variation for relative width of the M 2–3 trigonid, which is nevertheless always wider than the talonid. Although difficult to judge on the worn teeth, an entoconulid appears to be missing from all specimens.   
 Dentary: On two observed dentaries (including the holotype), the posterior mental foramen is below the M 1 trigonid (Russell, 1964: pl. 15, fig. 6). The horizontal ramus deepens posteriorly like L. mirabilis and Te. reisi, the deepest part being below M 3.   
 Discussion   
 As with W. krumbiegeli, coefficients of variation for some molar size dimensions are rather high for a single species (Table 8). It is possible that as in W. krumbiegeli, this represents time averaging of populations represented by the reworked Walbeck fauna.
description: Published as part of Hooker, Jerry J. & Russell, Donald E., 2012, Early Palaeogene Louisinidae (Macroscelidea, Mammalia), their relationships and north European diversity, pp. 856-936 in Zoological Journal of the Linnean Society 164 (4) on pages 899-901, DOI: 10.1111/j.1096-3642.2011.00787.x, http://zenodo.org/record/5407240