Trachytherus spegazzinianus, AMEGHINO, 1889

Billet, Guillaume, Muizon, Christian De & Quispe, Bernardino Mamani, 2008, Late Oligocene mesotheriids (Mammalia, Notoungulata) from Salla and Lacayani (Bolivia): implications for basal mesotheriid phylogeny and distribution, Zoological Journal of the Linnean Society 152 (1), pp. 153-200 : 172-173

TRACHYTHERUS SPEGAZZINIANUS AMEGHINO, 1889

FIGURES 12B AND 16–18 , APPENDIX 4 ( TABLES A4 AND A 5)

Trachytherus Ameghino, 1889a: 1–8 , non Trachytherium Gervais, 1849, Ameghino 1889b: 919, plate 79 figs 1, 2, plate 97, fig. 3.

Trachytherus conturbatus Ameghino, 1891: 241 .

Proedium solitarium Ameghino, 1895: 623 .

Eutrachytherus conturbatus Ameghino, 1897: 339 .

Proedrium solitarium Ameghino, 1897: 431 .

Ameghinotherium curuzucuatiense Podestá, 1899 .

Coresodon cancellatus Ameghino, 1901: 374 .

Isoproedium solitarium Ameghino, 1904: 117 .

Eutrachytherus grandis Loomis, 1914: 82 , fig. 49.

Trachytherus curuzucuatiense Reguero, 1993: 111, 1999 : PhD.

Trachytherus soriai Reguero, 1999 : PhD.

Anatrachytherus soriai Reguero & Castro, 2004: 45–64 .

Holotype: MACN A235 : right maxillary and premaxillary with broken I1, P2–M2 and broken M3 (figured in Ameghino, 1889b) ( Fig. 16A ).

Referred specimens: MACN A52-492 : palate with right P4 and M3 broken, M1–2 labially broken, and left M1 broken, M2, and mesial part of M3 ; MACN A52-494 : three isolated teeth probably from different individuals: (1) left I1, (2) right M1, (3) right M1 (?) ; MACN A52-491 : fragment of premaxillary with left I1 ; MACN A52-566 : right maxillary with dP3–4, M1 (holotype of Coresodon cancellatus Ameghino, 1901 ) ; MACN A52-567 : right dP3 ; MACN A52-493 : right I1 ; MACN A52-489 : right mandible with m1–3 ; MACN A52-498 : undetermined premolar (right p3 or 4?), and left m1–2 ; MACN A52-497 : right m2–3 ; MACN A52-496 : fragments of right mandible with broken p4–m1 and complete m3 ; MACN A52-490 : mandible with right i2, p2–m2 and left i1–2, p2–m3 (holotype of Anatrachytherus soriai ) ; MACN A52- 495 : symphysis without teeth (type of Proedrium solitarium ) ; MACN 6867 : incomplete skull with abrased cheekteeth (holotype of Trachytherus (Ameghinotherium) curuzucuatiense ) ; MLP 52 -XI- 2-1: left maxillary and premaxillary with I1, P2–M2 ( Fig. 16B ) ; AMNH 29564 : palate with right M1–3 and left dP3–4, M1–2 ; ACM 3264 : incomplete skull with left I1–3, P2–M3 . ACM s/n: left M1–2 (type of Trachytherus grandis ); FMNH P13281: incomplete restored skull with right M1–3 and left P3–M3 ; FMNH P13381: left M3; UNPSJB PV-112: incomplete skull with right I1, P3–M3 and left P3–M3. Moreover, numerous specimens from El Pajarito, Chubut Province, Argentina, are housed in the Museo de Ciencias Naturales de La Plata (catalogued as MLP 61 -VI-11-), and others from Lacayani, Bolivia, are housed in the Muséum national d’Histoire naturelle, Paris, France ( LAC 2 , and from LAC 14 to LAC 22 ), and in the Museo Nacional de Historia Natural , La Paz, Bolivia (MNHN-BOL-V) .

Marshall et al. (1986) also mentioned four AMNH specimens (from the Deseadan Patagonian locality of Las Cascadas, Chubut, Argentina): AMNH 116424 as T. spegazzinianus, AMNH 116420, AMNH 116423 and AMNH 116442 as T. sp. (we were not able to see and study these specimens).

Localities: According to Ameghino (1889b), the holotype MACN A235 comes from the Neuquén Province, Argentina. However, on a note with the specimen, the locality name ‘Santa Cruz’ has been substituted by ‘Neuquén’, probably by Bryan Patterson (A. Kramarz, pers. comm.). The reason for this correction is unknown. Furthermore, Reguero (1999) stated that ‘according to more precise data, these remains appear to come from the centre of Chubut and have been collected by Carlos Ameghino’. The exact locality of the holotype is therefore unknown. Specimen MLP 52-XI-2-1 must come from the same locality (see Discussion).

MACN A52-492 , MACN A52-491 , MACN A52-566 , MACN A52-567 , MACN A52-493 , MACN A52-489 , MACN A52-498 , MACN A52-496 , MACN A52-490 , UNPSJB PV 112, AMNH 29564 , ACM 3264 , ACM s/n and FMNH P13281 come from Cabeza Blanca, Chubut Province, Argentina (personal observation on specimen labels and Reguero, 1999) . MACN A52- 495 (type of Proedrium solitarium ) comes from La Flecha, Santa Cruz Province, Argentina ( Reguero & Castro, 2004). Several MACN specimens are of unspecified origin. FMNH P13381 comes from Pico Truncado, Santa Cruz Province, Argentina ( Reguero, 1999) . MACN 6867 (holotype T. curuzucuatiense ) comes from Arroyo Castillo , Department of Curuzú Cuatiá, Corrientes Province, Argentina ( Reguero, 1999) .

Finally, there are also numerous remains ( MLP) from El Pajarito, Chubut Province, Argentina, and others ( SAL and MNHN-BOL-V) from Bolivia, Lacayani (see Discussion) .

Figures

Figure 12. Restored ontogenetic series of M1. A, eight stages of Trachytherus alloxus from (1) SAL 1020, (2) SAL 750, (3) UF 149251, (4) SAL 808, (5) SAL 10, (6) SAL 690, (7) SAL 289 and (8) SAL 880. B, four stages of Trachytherus spegazzinianus from (1) MACN A52-566, (2) MACN A235, (3) MACN A52-492 and (4) FMNH P13281 (this last specimen after Patterson, 1934c). Scale bar = 1 cm.

Figure 16. Upper dentition of Trachytherus spegazzinianus. A, holotype, MACN A235, partially restored with right and left I1, P2–M3 (after Ameghino, 1889b). B, partial palate, with left I1, P2–M2, MLP 52-XI-2-1. C, upper right (reversed) dP3–4, M1, MACN A52-566. Scale bar = 1 cm.

Figure 17. A, holotype of T. curuzucuatiense (Podestá, 1889) = T. spegazzinianus, MACN 6867. B and C, holotype of Anatrachytherus soriai Reguero & Castro, 2004 = T. spegazzinianus, MACN A52-490; B, occlusal view; C, lateral view. Scale bar = 1 cm.

Figure 18. Trachytherus spegazzinianus from Lacayani. A, left M1, LAC 14. B, right (reversed) M2–3, MNHN-BOL-V 010725. C, right dentary with p3–4, m1 (or p4, m1–2), LAC 19. D, left maxillary with dP3–4, LAC 4. Scale bar = 1 cm.