Walshina esmaraldensis, López-Torres & Silcox & Holroyd, 2018

López-Torres, Sergi, Silcox, Mary T. & Holroyd, Patricia A., 2018, New omomyoids (Euprimates, Mammalia) from the late Uintan of southern California, USA, and the question of the extinction of the Paromomyidae (Plesiadapiformes, Primates), Palaeontologia Electronica (37 A) 21 (3), pp. 1-28 : 7

Walshina esmaraldensis gen. et sp. nov.

Figures 4.1-4.4 , 5.2, 5.5 , 6.1-6.19

zoobank.org/ 9E482E98-74DA-4ECC-9BE1-6AA10C07D41F

Phenacolemur cf. shifrae Mason, 1990 ; Walsh, 1996.

Holotype. LACM 40198 , left M 1.

Hypodigm. M 2: SDSNH 42268, 62850, 87336, 87337; M 3: SDSNH 76267; M 1: SDSNH 76337, 87331; M 2: SDSNH 76338, 87332, 87333; M 3: SDSNH 72583, 76266, 76339, 87334, 87335.

Type locality. LACM (CIT) 180, north of Simi Valley , Ventura County, California, USA. Late Uintan (Ui3) .

Etymology. In reference to the localities of Emerald Ridge (Vulgar Latin: esmaraldus).

Diagnosis. Intermediate in size between W. mcgrewi comb. nov. and W. shifrae comb. nov. Differs from W. mcgrewi comb. nov. in having a hypoconulid closer to the hypoconid than to the entoconid on M 2, similar to W. shifrae comb. nov. Very large hypoconulids on M 1 and M 2, whereas they are weakly developed in W. mcgrewi comb. nov. and W. shifrae comb. nov. M 2 trigonid and talonid of similar width, whereas W. mcgrewi comb. nov. and W. shifrae comb. nov. have significantly wider M 2 talonid bases relative to the trigonid base. M 3 with larger paraconid and taller metaconid relative to the protoconid than in W. shifrae comb. nov. Hypoconulid lobe of M 3 not expanded as far distally from the apex of the hypoconulid as in W. shifrae comb. nov. Differs from W. mcgrewi comb. nov. (but not W. shifrae comb. nov.) in having upper molars with smaller distolingual basins. In mesial view, M 1 with a less clearly delineated preprotocrista, like W. mcgrewi comb. nov. M 2 with a much more lingually expanded protocone lobe than in W. shifrae comb. nov. (but not in W. mcgrewi comb. nov.).

Figures

FIGURE 4. Environmental SEM images of four teeth of Walshina esmaraldensis gen. et sp. nov. 1: left M3, SDSNH 76276; 2: right M1, SDSNH 76337; 3: right M2, SDSNH 76338; 4: right M3, SDSNH 72583. All teeth are in occlusal view. Arrow indicates the location of the fovea.

FIGURE 5. Photographs taken with digital camera (1, 4-11) and Micro-CT scan reconstructions generated using Avizo 7 (2, 3). Walshina shifrae comb. nov. (1, 4, 7, 10) – 1: right M1, CM 15797 (holotype; mirrored), in occlusal view; 4: left M2, CM 15103, in occlusal view; 7: left M, CM 21637, in occlusal view; 10: left M; CM 15726, in occlusal view. 2 3 Walshina esmaraldensis gen. et sp. nov. (2, 5) – 2: left M1, LACM 40198 (holotype), in occlusal view; 5: left M2, SDSNH 62850, in occlusal view. Walshina mcgrewi comb. nov. (3, 6, 8, 9, 11) – 3: left M1, CM 15635 (holotype), in occlusal view; 6: left M2, CM15794, in occlusal view; 8, 9, 11: left mandibular fragment with M, CM 29005, in occlusal 2 (8), buccal (9), and lingual (11) views.

FIGURE 6. Micro-CT scan reconstructions of specimens of Walshina esmaraldensis gen. et sp. nov. generated using Avizo 7: 1: left M1, LACM 40198 (holotype), in occlusal view; 2: left M2, SDSNH 87336, in occlusal view; 3: lingual fragment of a left M2, SDSNH 87337, in occlusal view; 4: lingual fragment of a right M2, SDSNH 42268, in occlusal view; 5, 6, 9, 10: left M2, SDSNH 87332, in occlusal (5), buccal (6), mesial (9) and lingual (10) views; 7, 8, 11, 12: mesial fragment of a left M1, SDSNH 87331, in occlusal (7), buccal (8), mesial (11) and lingual (12) views; 13, 14, 17, 18: left M3, SDSNH 87334, in buccal (13), occlusal (14), lingual (17) and mesial (18) views; 15, 16, 19: distal fragment of a right M3, SDSNH 87335, in buccal (15), occlusal (16) and lingual (19) views.