Craniodental anatomy of late Oligocene archaeohyracids (Notoungulata, Mammalia) from Bolivia and Argentina and new phylogenetic hypotheses Author Billet, Guillaume Author Patterson, Bryan Author Muizon, Christian De text Zoological Journal of the Linnean Society 2009 2009-02-28 155 2 458 509 https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2008.00445.x journal article 10.1111/j.1096-3642.2008.00445.x 0024-4082 5444761 ARCHAEOHYRAX AMEGHINO, 1897 Diagnosis: Members of Archaeohyrax are characterized by the presence of a well-marked labial sulcus on the talonid of m3, an unambiguous synapomorphy of our cladistic analysis. This character is also found as a convergence in hegetotheriids. However, the sulcus is shallower and wider in Archaeohyrax and therefore the two conditions may not be homologous. Other characters may diagnose this clade phylogenetically, but they depend on optimization (see discussion of our phylogenetic analysis). Type species: Archaeohyrax patagonicus Ameghino, 1897 Type locality: Cabeza Blanca (see below), Chubut , Argentina . Included species: Archaeohyrax patagonicus Ameghino, 1897 , Archaeohyrax suniensis sp. nov. ARCHAEOHYRAX SUNIENSIS SP. NOV. FIGURES 1–17 , APPENDIX S1–4 ( TABLES 1 , 2 , 4 ) Archaeohyrax sp. nov. Reguero & Cifelli, 1997 . Protarchaeohyrax sp. nov. Reguero & Cifelli, 1997 . Archaeohyrax sp. nov. MacFadden et al. , 1985 . Holotype : SAL 4: skull and mandible of a young adult, with right I1, I3-M2, left dI1-2, I3, P1-M3, right p1-m2 (m3 is covered with matrix), left p2-m3 ( Figs 2 , 3 ). Paratypes : MNHN-BOL-V 006730: skull and mandible associated; SAL 183: rostrum with right and left c-m3; MNHN-BOL-V 007147: mandible with right i1, p1-m3 and left i1-m3; YPM-PU 23701: rostrum with right and left p2-m3; SAL 310: mandible with right i2, p2-m3 and left p3-m3. Figure 2. Archaeohyrax suniensis , cranium of the holotype, SAL 4. A, ventral view. B, dorsal view. C, right lateral view. Scale bar = 1 cm. Referred specimens: See Appendix S1. Locality: Salla-Luribay, Bolivia . Diagnosis: Differs from A. patagonicus in: smaller size; smaller facial extent of the premaxillaries, not extending further posteriorly than the level of C; smaller number of teeth exhibiting simultaneously a fossette or fossetid (i.e. P3-M2 & p3-m 2 in A. suniensis ; P2-M3 & p2-m 3 in A. patagonicus ); more hypsodont cheek teeth, almost hypselodont; second mental foramen situated more anteriorly than in A. patagonicus ; stylomastoid foramen situated closer to the tympanohyal recess. Figure 3. Archaeohyrax suniensis sp. nov. , schematic representation of the dentition of SAL 4. A, upper jaw with right I3-M2, left dI1-2, I3, P1-M3. B, lower jaw with right p1-m2 (m3 is covered with matrix), left p2-m3. Mesial at the top. Scale bar = 1 cm. Etymology: from suni, an Aymara word that refers to the highland Altiplano in Bolivia . Distribution: Deseadan SALMA , late Oligocene. Specimens all come from the Salla section ( MacFadden et al. , 1985 ) but most are from unit 5, Branisella level.