Appendix 1: List of characters used in the cladistic analysis

  1. Hypsodonty. 0= brachyodont; 1= protohypsodont; 2= euhypsodont. Additive.
  1. Hypoflexus/id isolated from parafossette/metafossettid in adult stages. 0= present; 1= absent.
  1. Transverse penetration of hypoflexus/id in adult stages. 0= halfway across the crown or less; 1= more than halfway across the crown.
  1. Number of transverse crests on M1-M2 in adult stages. 0= 5; 1= 4; 2= 3; 3= 2. Additive.
  1. Cement. 0= absent; 1= present.
  1. Lower cheek teeth strongly juxtaposed. 0= absent 1= present.
  1. Very compressed valleys in adult stages (elasmodonty). 0= absent; 1= present.
  1. Leading edgeswider than trailing edges. 0= absent; 1= present.
  1. MetalophulidII in juvenile stages. 0= transverse, labially attached to the posterior arm of protoconid;1= transverse, isolatedlabially (anterior valley Y-shaped); 2= oblique, labially connected to anterolophid; 3= absent. Non additive. In Dinomys and Tetrastylus the second crest is interpreted as the metalophulid II following Nasif (2011).
  1. Upper incisor with flat anterior face and enamel equally far on lateral and medial faces (modified from Patterson and Wood 1982). 0= absent; 1= present.
  1. Posterior extension of the lower incisor (modified from Fields 1957; Kramarz 2001).0= posterior to m3; 1= below m3; 2= below m2; 3= below m1. Additive.
  1. Fossa for insertion of M. nasolabialis profundus. 0= shallow, undifferentiated; 1= as a deep groove on premaxillary above incisors.
  1. Nasals widest point (modified from Patterson and Wood 1982). 0= anterior; 1= middle. In S. osbornianus this character is coded as non applicable, because the nasals are as wide anteriorly as in the middle portion.
  1. Rostrumlong, diastema longer than P4-M3 length(modified from Patterson and Wood 1982). 0= absent. 1= present.
  1. Rostrum sloping upwards on ventral surface (modified from Patterson and Wood 1982). 0= present; 1= absent.
  1. Premaxillaries posteriorly longer than nasals (modified from Kramarz, 2001). 0= absent; 1= present.
  1. Frontals penetrate between maxillaries and premaxillaries. 0= absent. 1= present.
  1. Large rostral opening of the nasolacrimal canal (modified from Patterson and Wood 1982; Kramarz 2001). 0= absent. 1= present.
  1. Groove in bottomof infraorbital foramen laterally limited by a distinct bony wall (modified from Fields 1957;Patterson and Wood 1982; Kramarz 2001). 0=absent; 1= present.
  1. Base of upper incisors excluded from rostral masseteric fossa (modified from Patterson and Wood 1982). 0= absent; 1= present.
  1. Relative position of the dorsal root of the zygoma (modified from Fields 1957; Kramarz 2001). 0= anterior to the limit between M1-M2; 1= posterior to the limit between M1-M2.
  1. Frontals longer than parietals (modified from Fields 1957). 0=absent; 1= present.
  1. Lacrimal-jugal contact (modified from Fields 1957). 0= absent; 1= present.
  1. Anterior margin of internal nares (modified from Fields 1957). 0= anterior to M3; 1= at M3 or posterior.
  1. Premaxillary-maxillary suture (modified from Patterson and Wood 1982). 0= straight across incisive foramen; 1= turns back at incisive foramen.
  1. Cheek tooth rows strongly converge anteriorly (modified from Patterson and Wood 1982; Kramarz 2001). 0= absent; 1= present.
  1. Sagittal crest (modified from Fields 1957). 0= present; 1= absent.
  1. External auditory meatus connected to accessory ventral opening (modified from Fields 1957). 0= present; 1= absent.
  1. Squamosal-mastoid contact (modified from Kramarz 2001). 0= absent, lateral process of supraoccipital well developed; 1=present, lateral process of supraoccipital reduced.
  1. External acoustic meatus as a complete tube oriented dorsally (modified from Kramarz 2001). 0= absent; 1= present.
  1. Dorsal exposure of the epitympanic recess (modified from Kramarz 2001). 0= absent; 1= present.
  1. Paracondyles (sensu Ameghino 1916; Rinderknecht et al. 2011). 0= absent; 1= present.
  1. Concavity of the mandibular diastema (modified from Kramarz 2001). 1= concave, diastema much lower than the alveolar line; 0= plane, diastema almost at the same height of the alveolar line.
  1. Mental foramen (modified from Kramarz 2001). 0= present; 1= absent.
  1. mandibular symphysis with enlarged digastric crest (modified from Fields 1957). 0= absent; 1= present.
  1. Masseteric crest (modified from Kramarz 2001). 0= normally developed; 1= reduced or absent.
  1. Coronoid process (modified from Fields 1957). 0= normal; 1= vestigial.
  1. Very deep hystricognathous groove (sensu Woods and Howland 1979). 0= absent; 1= present.
  1. lateral fossa for mandibular insertion of masseter superficialis muscle. 0= reduced or absent; 1= very developed as a deep groove at the base of the coronoid process.

Appendix 2: Data matrix

Taxa/Characters / 1 / 1 / 1 / 1 / 1 / 1 / 1 / 1 / 1 / 1 / 2
1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 0 / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 0
Prospaniomys / 0 / 0 / 0 / 1 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / ? / ? / 0 / 0 / 0 / 0 / ? / 0 / 1
Branisamys / 0 / 1 / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 1 / 1 / ? / 1 / 0 / 0 / 0 / 1 / ? / 0 / 0
Scleromys osbornianus / 1 / 0 / 0 / 2 / 0 / 0 / 0 / 0 / 1 / 1 / 0 / 0 / - / 1 / 0 / 0 / 1 / ? / 0 / 0
"Scleromys"shurmanni / 1 / 0 / 0 / 1 / 0 / 0 / 0 / 0 / 2 / 0 / 0 / 0 / 0 / 1 / 1 / 0 / 1 / 0 / 0 / 0
Tetrastylus / 2 / ? / ? / 1 / 1 / 0 / 1 / 1 / 2 / ? / 0 / 1 / ? / 1 / 0 / 0 / 0 / 0 / 0 / 0
Dinomys / 2 / ? / ? / 1 / 1 / 0 / 1 / 1 / 2 / 1 / 0 / 0 / 1 / 0 / 0 / 0 / 0 / 0 / 1 / 0
Garridomys / 1 / 0 / 1 / 2 / 1 / 0 / 0 / 1 / 1 / ? / 1 / ? / ? / ? / ? / ? / ? / ? / 1 / ?
Eoviscaccia / 1 / 0 / 1 / 3 / 1 / 0 / 1 / 1 / 3 / ? / ? / ? / ? / ? / ? / ? / ? / ? / 1 / ?
Prolagostomus / 2 / ? / - / 3 / 1 / 1 / 1 / 1 / - / 0 / 1 / ? / ? / 1 / 1 / 0 / ? / 1 / 1 / 0
Lagostomus / 2 / ? / - / 3 / 1 / 1 / 1 / 1 / - / 1 / 1 / 1 / 1 / 1 / 1 / [01] / 1 / 1 / 0 / 0
Chinchilla / 2 / ? / - / 2 / 1 / 0 / 1 / 1 / - / 0 / 3 / 0 / - / 1 / 1 / 1 / 1 / 1 / 1 / 1
Lagidium / 2 / ? / - / 2 / 1 / 0 / 1 / 1 / - / 0 / 3 / 1 / 1 / 1 / 1 / 1 / 1 / 1 / 1 / 1
Neoepiblema / 2 / ? / ? / 2 / ? / 0 / 0 / 0 / - / ? / ? / 0 / 0 / 1 / 1 / 0 / 0 / 0 / 0 / 0
Taxa/Characters / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 2 / 3 / 3 / 3 / 3 / 3 / 3 / 3 / 3 / 3 / 3
1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 0 / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9
Prospaniomys / 0 / 1 / 0 / 0 / 0 / 0 / 1 / 1 / 0 / 0 / 1 / 0 / 1 / 0 / 0 / 0 / 0 / 0 / 0
Branisamys / ? / 1 / ? / ? / 1 / 0 / ? / ? / ? / 0 / ? / ? / 0 / ? / ? / 0 / ? / 1 / 0
Scleromys osbornianus / 0 / 1 / 0 / 0 / 0 / 0 / 1 / 0 / 1 / 0 / 0 / ? / 0 / 0 / 0 / 0 / 0 / 1 / 0
"Scleromys"shurmanni / 0 / 1 / 0 / 1 / 1 / 0 / 1 / 0 / ? / 0 / 0 / ? / 0 / 0 / 1 / 0 / 0 / 1 / 0
Tetrastylus / 1 / 1 / ? / 1 / 0 / 1 / 1 / 0 / 1 / 0 / 0 / 1 / 1 / 1 / 1 / 0 / 1 / 1 / 0
Dinomys / 0 / 0 / 0 / 1 / 1 / 1 / 1 / 0 / 1 / 0 / 0 / 1 / 1 / 0 / 1 / 0 / 1 / 1 / 0
Garridomys / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / 0 / 0 / 0 / 0 / 0 / 0 / 0
Eoviscaccia / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ? / ?
Prolagostomus / ? / ? / ? / 0 / 0 / 1 / 1 / 1 / 0 / 1 / 0 / 0 / 1 / 0 / 0 / 1 / 0 / 0 / 1
Lagostomus / 1 / 1 / 1 / 0 / 0 / 1 / 0 / 1 / 0 / 1 / 0 / 0 / 1 / 1 / 0 / 1 / 0 / 0 / 1
Chinchilla / 1 / 1 / 0 / 0 / 0 / 1 / 1 / 1 / 0 / 1 / 1 / 0 / 1 / 0 / 0 / 1 / 0 / 0 / 1
Lagidium / 1 / 1 / 1 / 0 / 0 / 1 / 1 / 1 / 0 / 1 / 1 / 0 / 1 / 0 / 0 / 1 / 0 / 0 / 1
Neoepiblema / 0 / 1 / 0 / 1 / 0 / 1 / 0 / 0 / 0 / 0 / 0 / 0 / ? / ? / ? / ? / ? / ? / ?

Appendix 3: List of specimens of each taxon and bibliographic sources used for the phylogenetic analysis.

Prospaniomys priscus Ameghino. MACN A 52-131 (holotype), 52-132 – 52-137, 52-139 – 52-141, MACN PV CH1913, MPEF-PV 5039.

Branisamys luribayensis Hoffstetter and Lavocat. MLP 08-XII-15-1(Cast of MNHN SAL 28), Lavocat (1976), Patterson and Wood (1982).

Scleromys osbornianus Ameghino. MACN A 10121 (holotype), MACN A 4321, 4344, 4363, 5691, 5692, 10136 – 10142, Scott (1905).

“Scleromys” schurmanni Stehlin. UCMP 38987, Fields (1957).

Tetrastylus intermedius Rovereto. MACN Pv 8323.

Dinomys branickiiPeters. MACN Ma 12961, Ellerman (1940).

Eoviscaccia spp. MACN Pv CH1862 –CH1885, Vucetich (1989), Kramarz (2001).

Prolagostomus spp. MACN A 367 – 369, 389 – 391, 395 – 398, 4424 – 4450, 10868b, MACN Pv unnumbered, MLP-91-IX-2-165, Scott (1905).

Lagostomus maximus Desmarest. MACN Ma 53.66, 53.67, 53.69, 53.70, 48.109.

Chinchilla laniger (Molina). MACN Ma 52.90, 39.390, 16267, 20633.

Lagidium spp. MACN Ma 13933, 13936, 14312.

Neoepiblema spp. MACN Pv 2609, Negri (1999).

References

Ameghino C (1916) Algunas observaciones curiosas sobre una cabeza del género Tetrastylus de Catamarca. Physis 2:429-430

Ellerman JR (1940) The Families and Genera of Living Rodents. Vol 1. Rodents other than Muridae. Trustees of the British Museum (Natural History), London, 689 pp

Fields RW (1957) Hystricomorph rodents from the late Miocene of Colombia, South America. Univ Calif Publ Geol Sci 32:273-404

Kramarz AG (2001) Revision of the family Cephalomyidae (Rodentia, Caviomorpha) and new cephalomyids from the Early Miocene of Patagonia. Palaeovertebrata 30:51-88

Lavocat R (1976) Rongeurs Caviomorphes de l'Oligocéne de Bolivie II. Rongeurs du Bassin Déseadien de Salla - Luribay. Paleovertebrata 7:15-90

Nasif NL (2011)Los Dinomyidae (Rodentia, Caviomorpha) del Mioceno superior del Noroeste argentino. Su anatomía cráneo-dentaria. Ph.D dissertation. Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán

Negri RN, Ferigolo J (1999). Anatomía craniana de Neoepiblema ambrosettianus (Ameghino, 1889) (Rodentia, Caviomorpha, Neoepiblemidae) do Mioceno Superior-Plioceno, Estado do Acre, Brasil, e revisao das especies do genero. Boletim do Museu Paraense Emilio Goeldi 11:1-80

Patterson B, Wood AE (1982) Rodents from the Deseadan Oligocene of Bolivia and the relationships of the Caviomorpha. Bull Mus Comp Zool 149:371-543

Rinderknecht A, Bostelmann E. Ubilla M. (2011) New genus of giant Dinomyidae (Rodentia: Hystricognathi: Caviomorpha) from the late Miocene of Uruguay. J Mammal 92:169-178

Scott WB (1905) Mammalia of the Santa Cruz Beds. Volume V, Paleontology. Part III, Glires. In: Scott WB (ed) Reports of the Princeton University Expeditions to Patagonia, 1896–1899. Princeton University. E. Schweizerbart’sche Verlagshandlung (E. Nägele), Stuttgart, pp 384-490

Vucetich MG (1989) Rodents (Mammalia) of the Lacayani fauna re-visited (Deseadan, Bolivia). Comparison with new Chinchillidae and Cephalomyidae from Argentina. Bull Mus Natl Hist Nat, 4C 11:233-247

Woods CA, Howland EB (1979) Adaptative radiation of capromyid rodents: anatomy of the masticatory apparatus. J Mammal 60:95-116