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New genus of primitive wombat (Vombatidae, Marsupialia) from Miocene deposits in the Riversleigh World Heritage Area (Queensland, Australia)

Philippa Brewer, Michael Archer, Suzanne Hand, and Richard Abel

Plain Language Abstract

A new type of primitive wombat, described here, is the most complete early wombat found. Two fragments of the upper jaw, as well as isolated teeth were found within the Riversleigh World Heritage Area in northwestern Queensland, Australia. Previous to this, only a single species of wombat (Rhizophascolonus crowcrofti) was known from deposits older than 10 million years old, despite wombats having originated around 40 million years ago. In this study, we looked at differences in the size and shape of the teeth, skulls and skeletons of different wombats to produce a hypothesis of evolutionary relationships between them. The results indicate that the new wombat and Rhizophascolonus crowcrofti are most closely related to each other than to all other wombats. We then compared the cheek teeth of the different species of wombats and developed a hypothesis which explains the differences in the changing shape and function of the teeth over time. If this hypothesis is correct, it could be used to relate wombat tooth shape to diet, and potentially climate.

Resumen en Español

Nuevo género de wómbat primitivo (Vombatidae, Marsupialia) de los depósitos miocenos de la Riversleigh World Heritage Area (Queensland, Australia)

Se describe un nuevo género de wómbat primitivo, el cual es el wómbat temprano más completo encontrado. Dentro de la Riversleigh World Heritage Area, en el noroeste de Queensland, Australia, se encontraron dos maxilares parciales, así como dientes aislados. Con anterioridad, sólo se conocía una única especie de wómbat (Rhizophascolonus crowcrofti) de los depósitos de edad superior a los 10 Ma, a pesar de que se había estimado una edad de divergencia de 40 Ma entre los wómbats y su pariente vivo más cercano, el koala. Se realizó un análisis filogenético que incorporaba el nuevo taxón y carácteres dentarios, craneales y postcraneales frecuentemente usados, así como múltiples grupos externos con el fin de controlar las diversas especializaciones de familias estrechamente relacionadas y el problema del reconocimiento de homologías dentro de estos grupos. Los resultados indican que el nuevo taxón y R. crowcrofti son grupos hermanos en relación con todos los demás wómbats. Sobre la base de las comparaciones detalladas entre los elementos de la dentición yugal de los wómbats, se propone un modelo que explica las diferencias observadas en la morfología y la función de la dentición yugal en este grupo. Si este modelo es correcto, podría usarse para mapear la morfología respecto a la dieta, y potencialmente respecto al clima.

Palabras clave: nueva especie; nuevo género; filogenia; Marsupialia; Vombatidae; Australia

Traducción: Enrique Peñalver

Résumé en Français

Nouveau genre de wombat primitif (Vombatidae, Marsupialia) provenant de dépôts du Miocène dans la zone du patrimoine mondial de Riversleigh (Queensland, Australie)

Un nouveau genre de wombat primitif, décrit ici, est le wombat primitif le plus complet jamais trouvé. Deux maxillaires partiels, ainsi que des dents isolées, ont été trouvés dans la zone du patrimoine mondial de Riversleigh au nord-ouest du Queensland, en Australie. Avant cela, une seule espèce de wombat (Rhizophascolonus crowcrofti) était connu dans des dépôts de plus de 10 Ma, malgré une date de divergence d'environ 40 Ma entre les wombats et leurs plus proche parent vivant, le koala. Nous avons effectué une analyse phylogénétique incorporant le nouveau taxon, en utilisant des caractères dentaires, crâniens et postcrâniens et ainsi que plusieurs groupes externes afin de contrôler les diverses spécialisations des familles étroitement liées et le problème persistant de reconnaître les homologies au sein de ces groupes. Les résultats indiquent une relation sœur entre le nouveau taxon et R. crowcrofti par rapport à tous les autres wombats. A partir de comparaisons détaillées entre les dents de joue des wombats, nous proposons un modèle qui explique les différences observées dans la forme et la fonction des dents de joue de ce groupe. Si ce modèle est correct, il pourrait être utilisé pour cartographier la morphologie contre le régime alimentaire, et potentiellement le climat.

Mots-clés: nouvelles espèce; nouveau genre; phylogénie; Marsupialia; Vombatidae; Australie

Translator: Kenny J. Travouillon

Deutsche Zusammenfassung

Eine neue Gattung primitver Wombats (Vombatidae, Marsupialia) aus den miozänen Ablagerungen der Riversleigh World Heritage Area (Queensland, Australien)

Die hier beschriebene neue Gattung eines primitiven Wombats ist der vollständigste frühe Wombat, der jemals gefunden wurde. Im Riversleigh World Heritage Gebiet im Nordwesten von Queensland, Australien wurden zwei Maxilla-Teilstücke und isolierte Zähne gefunden. Davor war nur ein einziger Wombat (Rhizophascolonus crowcrofti) aus Ablagerungen älter als 10 Millionen Jahren bekannt, ungeachtet einer angenommenen Abweichung von 40 Millionen Jahren zwischen Wombats und deren nächsten Verwandten, den Koalas. Mit dem neuen Taxon führten wir eine phylogenetische Analyse durch wobei wir dentale, craniale und postcraniale Merkmale verwendeten ebenso wie multiple Außengruppen damit die diversen Spezialisierungen nah verwandter Familien und das bestehende Erkennungsproblem von Homologien in diesen Gruppen überprüft werden konnten. Die Ergebnisse verweisen auf eine Schwestergruppenbeziehung zwischen dem neuen Taxon und R. crowcrofti in Bezug auf alle anderen Wombats. Basierend auf den detaillierten Vergleichen zwischen den Wombat-Backenzähnen schlagen wir ein Modell vor, das die beobachteten Unterschiede in Form und Funktion der Backenzähne dieser Gruppe erklärt. Wenn dieses Modell korrekt ist, kann es zur Bestimmung der Morphologie und Ernährungsweise und möglicherweise auch des Klimas genutzt werden.

Keywords: neue Art; neue Gattung; Phylogenie; Marsupialia; Vombatidae; Australien

Translator: Eva Gebauer

Arabic

in progress

Translator: Ashraf M.T. Elewa

 

 

FIGURE 1. Map of Australia showing the location of Miocene wombat fossil sites.

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FIGURE 2. An animation of type specimen QM F23774, reduced for web viewing, based on CT data. The specimen was scanned at the Natural History Museum, London using a Metris X-Tek HMX ST 225 system. Volumes were constructed using CT PRO (Metris X-Tek, UK) and visualised using VG Studio Max 2.0 (Volume Graphics, Heidelberg, Germany). Click on image to run animation.

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FIGURE 3. Left maxillary fragment of Nimbavombatus boodjamullensis from Boid Site East (QM F23774). Left panel (photographs) of 1, occlusal (ventral) view of tooth row and 2, buccal (lateral) view. Scale bar represents 10 mm. Right panel (line drawings) of 3, occlusal (ventral) view and 4, buccal (lateral) view. Grey shading represents enamel.

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FIGURE 4. Left maxillary fragment of Nimbavombatus boodjamullensis from Creaser’s Ramparts Site (QM F23725). Photographs of 1, occlusal (ventral) view, 2, buccal (lateral) view and 3, lingual (medial) view. Scale bar represents 10 mm. 4, Line drawing of occlusal (ventral) view. Grey shading represents enamel. Asterisk marks presence of distinctive wear facet on trailing edge enamel (see text for details).

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FIGURE 5. Isolated molars of Nimbavombatus boodjamullensis from Creaser’s Ramparts. 1, Right M1 (QM F30339). 2, Left M1 (QM F51404). 3, Left Mx (probably M2 or M3) (QM F23773). From left to right views are: buccal, lingual, anterior, posterior, stereo of occlusal surface and line drawing of occlusal surface. Scale bar for photographs represents 10 mm. Grey shading on line drawings represents enamel. L indicates lingual side, B indicates buccal side.

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FIGURE 6. Lingual view of lower molars to show presence of enamel tracts (indicated by asterisks). 1,Nimbavombatus boodjamullensis. 2,Rhizophascolonus crowcrofti. 3, Warendja encorensis.

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FIGURE 7.1, Strict consensus tree for parsimony analysis including Marada arcanum. 2, Bootstrap support for single most parsimonious tree from analysis excluding Marada arcanum (see text for details). Vombatidae indicated in purple.

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FIGURE 8.Jaw movement during the power stroke in Nimbavombatus boodjamullensis. 1, Evidence of jaw movement on the surface of the cheek teeth. 2, Movement of the lower jaw during Phase I (left) and Phase II (right) of the power stroke.

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APPENDIX 1.

List of characters used in the phylogenetic analysis. Characters indicated by an asterisk are ordered in the analysis.

 

1.* Number of upper incisors (modified from Springer et al., 1997, Rougier et al., 1998, Wroe et al., 2000, Horovitz and Sánchez-Villagra, 2003 and Black et al., 2012): (0) More than three; (1) Two or Three; (2) One.

2. Size of I 1 relative to I 2 (Black et al., 2012): (0) Equal or similar in length; (1) Large, elongate.

3. Upper canine (modified from Springer et al., 1997, Horovitz and Sánchez-Villagra, 2003 by Black et al., 2012): (0) Present; (1) Absent or vestigal.

4.* Number of upper premolars (Black et al., 2012): (0) Three; (1) Two; (2) One.

5. Posterobuccal cusp on P 3 (Woodburne et al., 1987; Black and Archer, 1997; Myers and Archer, 1997; Black et al., 2012): (0) Absent; (1) Present.

6. Enamel extending down the buccal surface of P 3 and onto the root: (0) Absent; (1) Present.

7.* Size of P 3 relative to M 1 (modified from Black and Archer, 1997 and Black et al., 2012): (0) P 3 length greater than M 1 length; (1) P 3 length less than or equal to M 1 length; (2) P 3 length less than or equal to 80% of M 1 length.

8.* Molar morphology (Black et al., 2012): (0) Tribosphenic; (1) Selenodont; (2) Semi-lophodont/bunodont; (3) Lophodont but stylar cusps still evident on lophs; (4) Fully lophodont.

9. Hypselodont cheek teeth (modified from Murray, 1998; Black et al., 2012): (0) Absent; (1) Present.

10. Enamel noticeably thicker on trailing edge (lingual surface on upper molars and buccal surface on lower molars) relative to leading edge of molars (buccal surface on upper molars and lingual surface on lower molars): (0) Absent; (1) Present.

11.* Presence of enamel tracts that extends down the lingual surface of upper molars and buccal surface of lower molars: (0) Absent; (1) Moderate enamel tracts / changes in enamel height around the tooth; (2) Extensive enamel tracts / changes in enamel height around the tooth.

12. Anteriorly concave lower / anteriorly convex upper molar lophs (Black et al., 2012): (0) Absent; (1) Present.

13. M 1 with decrease in enamel height on lingual surface at constriction or just posterior to this: (0) Absent; (1) Present.

14.* Parastyle development on M 1 (Black and Archer, 1997; Black et al., 2012): (0) Absent/small; (1) Moderately developed expansion of anterobuccal tooth corner; (2) Large, cuspate and pyramidal.

15. Presence of a cusp on posterobuccal side of M 1 (and occasionally M 2) in position of St-E: (0) Absent; (1) Present.

16.* St-C larger and better developed than St-B on M 2 : (0) Absent; (1) Similar in size; (2) Present.

17. Presence of crest connecting paracone to St-B on M 2 : (0) Absent; (1) Present.

18.* Separation of stylar cusps C and D (modified from Myers and Archer, 1997 and Black et al., 2012): (0) Close together; (1) Separated; (2) Separated by a large trough.

19. Postprotocrista (Archer, 1984; Black et al., 2012): (0) Present; (1) Absent.

20. M 2 width of anterior moiety versus tooth length (modified from Springer et al., 1997; Horovitz and Sánchez-Villagra, 2003 by Black et al., 2012): (0) M 2 longer than wide; (1) M 2 width is greater or equal to length.

21. M 4 metaconule (Black et al., 2012): (0) Absent / significantly reduced and retracted towards posterior cingulum; (1) Distinct / cuspate.

22. Posteriorly increasing (upper) molar gradient (modified from Black, 2007 and Black et al., 2012): (0) Absent, M 4 / M 1 is less than or equal to 1; (1) Present, M 4 / M 1 is greater than 1.

23.* Number of lower incisors (modified from Springer et al., 1997, Rougier et al., 1998, Wroe et al., 2000, Luo et al., 2002, Horovitz and Sánchez-Villagra, 2003 and Black et al., 2012): (0) Two or more; (1) One.

24. Inclination angle of I 1 (Marshall et al., 1990; Springer et al., 1997; Horovitz and Sánchez-Villagra, 2003; Black, 2007; Black et al., 2012): (0) High (greater or equal to 30 degrees); (1) Low (less than 30 degrees).

25. Development of paraconid and paracristid on M 1 (modified from Myers and Archer, 1997, Horovitz and Sánchez-Villagra, 2003 by Black, 2007; Black et al., 2012): (0) Paraconid present and paracristid well-developed; (1) Paraconid weak or absent; paracristid present and distinct; (2) Paraconid and paracristid absent.

26. Protostylid on M 1 (Woodburne et al. 1987; Black and Archer 1997; Myers and Archer 1997; Springer et al. 1997; Black 2007): (0) Absent; (1) Present.

27. Cristid obliqua (modified from Black, 2007 and Black et al., 2012): (0) Well-developed, meets or approaches postprotocristid lingual to horizontal tooth midline; (1) Well-developed, meets or approaches postprotocristid buccal to horizontal tooth midline; (2) Weak / absent.

28. Distinct and separate paraconid on M 2-4 : (0) Absent; (1) Present.

29. Paraconid located on lingual side of tooth on M 2-3 (or preprotocristid / paracristid terminates on lingual side of tooth): (0) Present; (1) Absent, located close to midline or buccal side of tooth.

30. Paraconid connected to protoconid via crest on M 2-3 (or well-developed preprotocristid / paracristid): (0) Present; (1) Absent.

31. Presence of a crest connecting entoconid and hypoconid: (0) Absent; (1) Present.

32. Incisive foramen posterior (modified from Dawson, 1983b; Murray, 1998; Tedford, 2002): (0) Absent; (1) Present, the incisive foramina lie posteriorly, just anterior to P 3 , in a deep pocket at the rear of the diastema. The posterior position of the foramina correspondingly displaces the premaxillary-maxillary suture to a position just anterior to the cheek tooth.

33. Lateral edge of palate emarginated from I 1 to P 3 in ventral view (modified from Tedford, 2002): (0) Absent; (1) Present.

34. Palate width opposite first molar (ventral view) (Merrilees, 1967; Scott et al., 1988): (0) Narrow, less than buccolingual width of M 1 ; (1) Wide, equal to or greater than buccolingual width of M 1.

35. Median premaxillary process (Tedford, 2002): (0) Absent; (1) Well-developed or present as a low spine at the midline dorsal surface of the premaxilla.

36.* Position of infraorbital foramen: (0) Close to level of alveolar process; (1) Approximately midway between dorsal surface of skull and alveolar process; (2) Closer to dorsal surface of skull than alveolar process of tooth row.

37.* Posterior palatal vacuities (maxillopalatine vacuity) (modified from Archer, 1984, Reig et al., 1987, Rougier et al., 1998, Wroe et al., 2000, Horovitz and Sánchez-Villagra, 2003 and Black et al., 2012): (0) Extends anteriorly to a point anterior of M 3; (1) Confined within palate, opposite M 3-4; (2) Absent.

38.* Nasal aperture retracted beyond incisor arcade (modified from Black et al., 2012): (0) Absent or just posterior to incisor arcade; (1) Retracted to above diastema (or level of premaxillary-maxillary suture); (2) Retracted to above cheek tooth row.

39. Nasomaxillary suture length relative to nasopremaxillary suture length (dorsal view) (Scott et al., 1988): (0) Nearly same or greater; (1) Far less than nasopremaxillary suture length.

40. Separate left and right parietal ridges along entire length of parietal bone: (0) Absent; (1) Present.

41.* Masseteric process (Wroe et al., 1998; modified version in Black et al., 2012): (0) Absent; (1) Short; (2) Elongate.

42. Dorsoventral position of ventral extent of anterior zygomatic root (relative to the cheek tooth row): (0) Close to level of alveolar process; (1) Distant to alveolar process.

43. Anteroposterior position of ventral extent of anterior zygomatic root (relative to the cheek tooth row): (0) Above M 3 or M 4; (1) Above junction between M 2 and M 3 ; (2) Above M 2; (3) At junction between M 1 and M 2 or anterior to M 2.

44. Infraorbital shelf (Black et al., 2012): (0) Well-developed; (1) Weak.

45. Postglenoid process (Springer et al., 1997; Horovitz and Sánchez-Villagra, 2003; modified version in Black et al., 2012): (0) Present; (1) Absent.

46. Tympanic cavity roof elements (modified from Travoullion et al., 2010 and Black et al., 2012): (0) Alisphenoid (no squamosal contribution); (1) Alisphenoid and squamosal; (2) Squamosal (no alisphenoid contribution).

47. Tympanic floor elements (Black et al., 2012): (0) Alisphenoid; (1) Alisphenoid and squamosal; (2) Squamosal.

48.* Alisphenoid tympanic wing (modified from Springer et al., 1997, Wroe et al., 1998, Horovitz and Sánchez-Villagra, 2003 and Black et al., 2012): (0) Absent; (1) Short; (2) Moderate to elongate, extends under periotic.

49. Epitympanic fenestra developed in postglenoid cavity (Black et al., 2012): (0) Absent; (1) Present.

50. Non-auditory sinuses (Murray, 1986; Black et al., 2012): (0) Absent; (1) Present.

51. Posterior epitympanic fossa (modified from Murray, 1986; modified from Black et al., 2012): (0) Absent / weak; (1) Moderate to deep.

52.* Postglenoid cavity / epitympanic fossa (modified from Murray, 1998, Tedford, 2002, Louys, 2004 and Black et al., 2012): (0) Absent; (1) Present, but shallow; (2) Present and moderately extensive / deep.

53.* Rostral tympanic process of periotic (Rougier et al., 1998; Sánchez -Villagra and Wible, 2002; Horovitz and Sánchez-Villagra, 2003 modified version; Black et al., 2012): (0) Strong; (1) Weak / absent.

54. Posterior parietal width (Black et al., 2012): (0) Broad; (1) Narrow.

55. Interparietal (Louys et al., 2009; Black et al., 2012): (0) Present; (1) Absent.

56. Narrow mastoid strip on occiput (Murray, 1986; Black et al., 2012): (0) Absent; (1) Present.

57. Ventrolaterally flared mastoid process on occiput (Murray 1986; Black et al., 2012): (0) Absent; (1) Present.

58.* Length of articular surface (mandible) relative to length of cheek tooth row (modified from Scott et al., 1988): (0) Short, ratio of 0.4 or less; (1) Medium, ratio of 0.5 to 0.6; (2) Long, ratio of 0.7 or greater.

59.* Forward extent of ectalveolar groove of mandible (Dawson, 1983a): (0) Posterior of M 4; (1) Junction between M 3 and M 4 to mid M 4; (2) Adjacent to M 3.

60.* Depth of masseteric fossa (mandible) (Merrilees, 1967; Scott et al., 1988): (0) Shallow to medium; (1) Deep; (2) Very deep.

61. Angle of the anterior border of the ascending ramus (mandible) (modified from Hope and Wilkinson, 1982; Black, 2007; Black et al., 2012): (0) < 70°; (1) > or = 70°.

62.* Posterior extent of mandibular symphysis (mandible) (Black, 2007; Black et al., 2012): (0) Anterior to P 3; (1) Below P 3; (2) Below M 1; (3) Below M 2-3.

63.* Diastema length between I 1 and P 3 (modified from Black, 2007 and Black et al., 2012): (0) < 30% horizontal ramus length; (1) Approximately 30% horizontal ramus length; (2) > 30% horizontal ramus length.

64. Distance between anterior edge of P 3 and posterior edge of M 4 relative to length of horizontal ramus (mandible) (Black et al., 2012): (0) > 60%; (1) < or = 60%.

65. Flared masseteric eminences (mandible) (Murray, 1998; Black et al., 2012): (0) Absent / weak; (1) Moderately to strongly flared.

66. Masseteric foramen (Black, 2007; Black et al., 2012): (0) Absent; (1) Present.

67. Fused mandibular symphysis: (0) Absent; (1) Present.

68. Cervical vertebrae: combined length of C3-C7 divided by width of C7 (Munson, 1992): (0) > 1.0 (long neck); (1) < 1.0 (short neck).

69. Humerus: max. width across distal end divided by length (Munson, 1992): (0) < or = 0.3; (1) > 0.3.

70. Humerus: deltoid ridge (Munson, 1992): (0) Has no lateral overhang, or a very minor one; (1) Has a large flaring overhang.

71.* Humerus: deltoid tuberosity (modified from Scott and Richardson, 1988): (0) Angle between deltoid and pectoral crests < 30°; (1) Angle between 30° and 40°; (2) Angle > 40°.

72. Ulna: anteroposterior thickness at semilunar notch divided by bone length (modified from Munson, 1992): (0) < or = 0.10; (1) > 0.10.

73. Ulna: length of olecranon process divided by bone length (Munson, 1992): (0) < 0.20; (1) > or = 0.20.

74. Ulna: max. anteroposterior thickness at coronoid process divided by bone length (Munson, 1992): (0) < 0.2; (1) > or = 0.2.

75. Radius: length (Munson, 1992): (0) > length of humerus; (1) < or = length of humerus.

76. Radius: anteroposterior thickness of distal end divided by bone length (Munson, 1992): (0) < or = 0.1; (1) > 0.1.

77. Cuneiform: position relative to scapholunar (Munson, 1992; Weisbecker and Archer, 2008): (0) Directly lateral to scapholunar; (1) More proximal than the scapholunar.

78. Cuneiform: ridge between ulnar and pisiform facets (Weisbecker and Archer, 2008): (0) Middle section sinks below the rim of the cuneiform; (1) High rising throughout, straight.

79. Pisiform: area of ulnar facet (Munson, 1992; Weisbecker and Archer, 2008): (0) < area of cuneiform facet; (1) > or = area of cuneiform facet.

80. Pisiform: width divided by thickness (Munson, 1992): (0) < 0.5; (1) > or = 0.5.

81. Scaphoid: distal surface (Weisbecker and Archer, 2008): (0) Single facet, smooth; (1) Separated into two distinct facets.

82. Scaphoid: distolateral process (Weisbecker and Sánchez-Villagra, 2006): (0) Absent; (1) Present.

83. Unciform: area of MC V facet (Munson, 1992; Weisbecker and Archer, 2008): (0) < MC IV facet; (1) > or = area of MC IV facet.

84. Unciform: hamate process (modified from Munson, 1992, Weisbecker and Sánchez-Villagra, 2006 and Weisbecker and Archer, 2008): (0) Large, hooked and curves medially; (1) Reduced, not as hooked and does not curve as far medially.

85.* MC I: max. width divided by length (modified from Munson, 1992 by Weisbecker and Archer, 2008): (0) < 0.4 ; (1) 0.4 to 0.5; (2) > 0.5.

86. MC II: proximal end (Munson, 1992; Weisbecker and Archer, 2008): (0) Mediolaterally compressed; (1) Expanded and concave.

87. MC III: facet for MC IV (modified from Munson, 1992): (0) Proximal only to ligament pit (no dorsal component); (1) Dorsal to ligament pit (no proximal component); (2) Dorsal and proximal to ligament pit.

88. MC III: facet for MC IV (modified from Munson, 1992 by Weisbecker and Archer, 2008): (0) Facing laterally or only slightly distally slanted; (1) Strongly distally slanted or completely facing distally.

89. MC III: magnum facet (modified from Munson 1992): (0) Grooved or concave; (1) Convex or flat to slightly convex.

90. MC III: MC II facet (Munson, 1992; Weisbecker and Archer, 2008): (0) Separate, distinct, and lateral to the magnum facet; (1) Continuous with the magnum facet.

91.* MC V: max. width of distal end divided by length (modified from Munson, 1992 and Weisbecker and Archer, 2008): (0) < 0.4; (1) 0.4 to 0.5; (2) > 0.5.

92.* Proximal phalanges II to V of manus, IV and V only in pes: mid-shaft width divided by length (modified from Munson, 1992 and Weisbecker and Archer, 2008): (0) < 0.3; (1) 0.3 to 0.4; (2) > 0.4.

93. Proximal phalanges, manus or pes: distal ends (Munson, 1992; Weisbecker and Archer, 2008): (0) Not tapered; (1) Dorsoventrally tapered, so that the articulation for the medial phalanx faces ventrally.

94.* Medial phalanx III of manus or IV of pes: length divided by length of corresponding metapodial (modified from Munson, 1992 and Weisbecker and Archer, 2008): (0) < 0.30; (1) 0.30 to 0.40; (2) > 0.40.

95. Pelvis: dorsoventral height at symphysis divided by width at mid-ischium (Munson, 1992): (0) < 0.8; (1) > or = 0.8.

96. Pelvis: ilium (Munson, 1992): (0) Only slightly dorsoventrally flattened, or mediolaterally flattened; (1) Greatly dorsoventrally flattened.

97.* Pelvis: width of iliac crest divided by length of ilium (Munson, 1992): (0) < 0.30; (1) 0.30 to 0.50; (2) > 0.50.

98. Epipubics: width at mid-bone divided by length X 100 (Munson, 1992): (0) < 10; (1) > or = 10.

99. Femur: width of proximal end divided by length (Munson, 1992): (0) < 0.3; (1) > or = 0.3.

100. Tibia: length (Munson, 1992): (0) > or = length of femur; (1) < length of femur.

101. Fibula: lateral notch on distal end (Munson, 1992): (0) Clearly present; (1) Extremely slight or absent.

102. Fibula: width of proximal end divided by bone length (modified from Munson, 1992): (0) < 0.10; (1) > or = 0.10.

103. Fibula: femoral facet (Munson, 1992): (0) Not present; (1) Present.

104. Astragalus: lateral tibial facet (modified from Munson, 1992): (0) Mostly convex; (1) Mostly concave.

105. Astragalus: head (modified from Munson, 1992): (0) Wider than long; (1) Narrow, mediolaterally compressed, or length and width are equal.

106. Cuboid (Munson, 1992): (0) No contact; (1) Contacts astragalus.

107. Cuboid: area of MT V facet (Munson, 1992): (0) < MT IV facet; (1) > or = area of MT IV facet.

108. Ectocuneiform: length divided by height (Munson, 1992): (0) > or = 0.8; (1) < 0.8.

109. Entocuneiform: MT I facet (Munson, 1992): (0) Saddle-shaped (concavo-convex); (1) Convex.

110. Entocuneiform: navicular facet (Munson, 1992): (0) Shorter than or equal to mesocuneiform facet; (1) Longer than mesocuneiform facet.

111. Metatarsal I: entocuneiform facet (Munson, 1992): (0) Mostly convex; (1) Strong concave component.

112. MT II and III: mid-shaft width divided by bone length (Munson, 1992): (0) < 0.15 ; (1) > or = 0.15.

113. MT IV: proximal end (Munson, 1992): (0) Square; (1) Mediolaterally tapered.

114. MT V versus MT III (modified from Munson, 1992): (0) MT III longer that MT V; (1) MT V longer than MT III.

115.* MT V: max. width divided by length (modified from Munson, 1992): (0) < 0.50; (1) 0.50 to 0.70; (2) > 0.70.

 

APPENDIX 2.

Data matrix used for phylogenetic analysis. ? indicates missing data; - indicates inapplicable character; polymorphic states indicated by both states in brackets, e.g., (01).

Didelphis marsupialis 0000100000 0-01120201 0000001100 0001000000 000?000200 00?0010000 10-1000000

0????????? ?????????? ????00000? ?????????? ?????

Perameles bougainville 0000?01000 0-020??101 0000002100 000100000- 001?0???00 ???0???000 00-1??0000

0010000000 0101002000 0000101000 0000100000 00010

Galadi speciosus 0000002000 0-000??001 000?001100 0001000000 0000000?00 0000100?00 10-1000???

?????????? ?????????? ????101?0? ?????????? ?????

Ngapakaldia tedfordi 1112002400 01001??210 111120201? 10?1012110 1011022011 1211110?00 122101??1?

?10?111111 1010202000 1102???111 1111011000 10111

Ilaria ilumindens 110210210? 0-01121200 11??110??? ???1??1??? 201??????? ????????0? 1?00101???

?111?0???? ????111111 ?11??????? ?????????? ??1??

Propalorchestes novaculocephalus ??12002300 0100121210 11112010?? 1101?12210 2021021?11 121111?210 122111????

?????????? ?????????? ?????????? ?????????? ?????

Nimiokoala greystanesi 1002102100 0-02101001 0010010010 00?1?0?010 1030?1??00 ??000????0 1300010???

?????????? ?????????? ?????????? ?????????? ?????

Priscileo roskellyae 1100000200 0-011??101 ?0101010?? 0001?00000 ?030011200 ?210100??0 ?10001????

?????????? ?????????? ?????????? ?????????? ?????

Lasiorhinus latifrons 2-12?1?211 20001012(01)0 0011?01001 10111211(01)1 0120122000 1210111121 1311111111

2111101111 10?121?111 2211012111 1111011111 ?1102

Nimbavombatus boodjamullensis 1?02012201 1011?????0 00???????? ??01?10??? 0020?????? ?????????? ??????????

?????????? ?????????? ?????????? ?????????? ?????

Phascolonus gigas 2-12?0??11 2?0??????0 ?011?????? ?1101?12?1 01?01????? ?2?????122 0301111111

2111111111 1?1121?1?1 221?112011 11110????? ?????

Rhizophascolonus crowcrofti ???????201 (12)?1??????0 ?????????? ?????????? ?????????? ?????????0 1?????????

?????????? ?????????? ?????????? ?????????? ?????

Vombatus ursinus 2-12?1?211 20011012?0 1010?01101 (01)000021111 0120122?00 1110111212 1311111111

1111111111 1001211111 2211012111 1111011111 11102

Warendja wakefieldi 2-12?1??11 2?0??????0 ?010?????? ?001?10??0 00101220?? ?1?01????0 0210110??1

1????????? ?????????? ?????????? ?????????? ?????

Muramura williamsi 11020?0200 00?100?201 1011101010 1000?0?1?0 20100????? 01??1?1110 11210?0000

000000???? ?????????? ????????11 0111??0??? ?????

Marada arcanum ???????200 00???????? ??11101010 1????????? ?????????? ????????00 0121010???

?????????? ?????????? ?????????? ?????????? ?????

APPENDIX 3.

Comparative dental measurements.

NODE
(from)
NODE
(to)
CHARACTER
NUMBER
CHANGE CHARACTER DESCRIPTION
  1 1 0→1 Number of upper incisors
    8 0→1 Molar morphology
    23 0→1 Number of lower incisors
    28 1→0 Distinct and separate paraconid on M2-4
    29 0→1 Paraconid located on lingual side of tooth on M2-3
    41 0→1 Masseteric process
    43 0→3 Anteroposterior position of ventral extent of anterior zygomatic root (relative to the cheek tooth row)
    46 0→1 Tympanic cavity roof elements
    62 0→1 Posterior extent of mandibular symphysis (mandible)
    66 0→1 Masseteric foramen
1 2 2 0→1 Size of I1 relative to I2
    8 1→2 Molar morphology
    25 0→1 Development of paraconid and paracristid on M1
    53 0→1 Rostral tympanic process of periotic
2 3 18 1→2 Separation of stylar cusps C and D
    31 0→1 Presence of a crest connecting entoconid and hypoconid
    38 0→1 Nasal aperture retracted beyond incisor arcade
    43 3→1 Anteroposterior position of ventral extent of anterior zygomatic root (relative to the cheek tooth row)
    63 0→1 Diastema length between I1 and P3
3 4 7 0→2 Size of P3 relative to M1
    20 1→0 M2 width of anterior moiety versus tooth length
    36 0→1 Position of infraorbital foramen
    51 0→1 Posterior epitympanic fossa
    62 1→2 Posterior extent of mandibular symphysis (mandible)
    69 0→1 Humerus: max. width across distal end divided by length
    72 0→1 Ulna: anteroposterior thickness at semilunar notch divided by bone length
    75 0→1 Radius: length
    101 0→1 Fibula: lateral notch on distal end
    107 0→1 Cuboid: area of MT V facet
4 5 3 0→1 Upper canine
    8 2→3 Molar morphology
    12 0→1 Anteriorly concave lower / anteriorly convex upper molar lophs
    14 1→0 Parastyle development on M1
    19 0→1 Postprotocrista
    25 1→2 Development of paraconid and paracristid on M1
    37 1→2 Posterior palatal vacuities (maxillopalatine vacuity)
    44 0→1 Infraorbital shelf
    49 0→1 Epitympanic fenestra developed in postglenoid cavity
    50 0→1 Non-auditory sinuses
    52 1→2 Postglenoid cavity / epitympanic fossa
    54 0→1 Posterior parietal width
4 6 86 0→1 MC II: proximal end
    87 2→1 MC III: facet for MC IV
    88 0→1 MC III: facet for MC IV
    89 0→1 MC III: magnum facet
    90 0→1 MC III: MC II facet
    93 0→1 Proximal phalanges, manus or pes: distal ends
6 7 6 0→1 Enamel extending down the buccal surface of P3 and onto the root
    11 0→1 Presence of enamel tracts that extends down the lingual surface of upper molars and buccal surface of lower molars
    41 1→0 Masseteric process
7 8 3 0→1 Upper canine
    9 0→1 Hypselodont cheek teeth
    11 1→2 Presence of enamel tracts that extends down the lingual surface of upper molars and buccal surface of lower molars
8 9 36 1→2 Position of infraorbital foramen
    40 0→1 Separate left and right parietal ridges along entire length of parietal bone
    42 0→1 Dorsoventral position of ventral extent of anterior zygomatic root (relative to the cheek tooth row)
    60 0→1 Depth of masseteric fossa (mandible)
    62 2→3 Posterior extent of mandibular symphysis (mandible)
9 10 33 0→1 Lateral edge of palate emarginated from I1 to P3 in ventral view
    35 0→1 Median premaxillary process
    52 1→2 Postglenoid cavity / epitympanic fossa
    59 1→2 Forward extent of ectalveolar groove of mandible
    71 1→2 Humerus: deltoid tuberosity
8 11 13 0→1 M1 with decrease in enamel height on lingual surface at constriction or just posterior to this

 

APPENDIX 4.

Cusp morphology of P3 to M2 of modern wombats compiled from CT scans of Lasiorhinus latifrons (SAM M4157 and SAM M1924) and Vombatus ursinus (NMV C10928 and NMV C3133). 1, Upper dentition of L. latifrons. 2, Upper dentition of V. ursinus. 3, Lower dentition of L. latifrons. 4, Lower dentition of V. ursinus. Abbreviations as follows: end refers to entoconid, hyd refers to hypoconid, ME refers to metacone, med refers to metaconid, MEL refers to metaconule, PA refers to paracone, PR refers to protocone, prd refers to protoconid.

appendix

APPENDIX 5.

List of unambiguous apomorphies. Node numbers correspond to Figure 7.2

NODE
(from)
NODE
(to)
CHARACTER NUMBER CHANGE CHARACTER DESCRIPTION
  1 1 0→1 Number of upper incisors
    8 0→1 Molar morphology
    23 0→1 Number of lower incisors
    28 1→0 Distinct and separate paraconid on M2-4
    29 0→1 Paraconid located on lingual side of tooth on M2-3
    41 0→1 Masseteric process
    43 0→3 Anteroposterior position of ventral extent of anterior zygomatic root (relative to the cheek tooth row)
    46 0→1 Tympanic cavity roof elements
    62 0→1 Posterior extent of mandibular symphysis (mandible)
    66 0→1 Masseteric foramen
1 2 2 0→1 Size of I1 relative to I2
    8 1→2 Molar morphology
    25 0→1 Development of paraconid and paracristid on M1
    53 0→1 Rostral tympanic process of periotic
2 3 18 1→2 Separation of stylar cusps C and D
    31 0→1 Presence of a crest connecting entoconid and hypoconid
    38 0→1 Nasal aperture retracted beyond incisor arcade
    43 3→1 Anteroposterior position of ventral extent of anterior zygomatic root (relative to the cheek tooth row)
    63 0→1 Diastema length between I1 and P3
3 4 7 0→2 Size of P3 relative to M1
    20 1→0 M2 width of anterior moiety versus tooth length
    36 0→1 Position of infraorbital foramen
    51 0→1 Posterior epitympanic fossa
    62 1→2 Posterior extent of mandibular symphysis (mandible)
    69 0→1 Humerus: max. width across distal end divided by length
    72 0→1 Ulna: anteroposterior thickness at semilunar notch divided by bone length
    75 0→1 Radius: length
    101 0→1 Fibula: lateral notch on distal end
    107 0→1 Cuboid: area of MT V facet
4 5 3 0→1 Upper canine
    8 2→3 Molar morphology
    12 0→1 Anteriorly concave lower / anteriorly convex upper molar lophs
    14 1→0 Parastyle development on M1
    19 0→1 Postprotocrista
    25 1→2 Development of paraconid and paracristid on M1
    37 1→2 Posterior palatal vacuities (maxillopalatine vacuity)
    44 0→1 Infraorbital shelf
    49 0→1 Epitympanic fenestra developed in postglenoid cavity
    50 0→1 Non-auditory sinuses
    52 1→2 Postglenoid cavity / epitympanic fossa
    54 0→1 Posterior parietal width
4 6 86 0→1 MC II: proximal end
    87 2→1 MC III: facet for MC IV
    88 0→1 MC III: facet for MC IV
    89 0→1 MC III: magnum facet
    90 0→1 MC III: MC II facet
    93 0→1 Proximal phalanges, manus or pes: distal ends
6 7 6 0→1 Enamel extending down the buccal surface of P3 and onto the root
    11 0→1 Presence of enamel tracts that extends down the lingual surface of upper molars and buccal surface of lower molars
    41 1→0 Masseteric process
7 8 3 0→1 Upper canine
    9 0→1 Hypselodont cheek teeth
    11 1→2 Presence of enamel tracts that extends down the lingual surface of upper molars and buccal surface of lower molars
8 9 36 1→2 Position of infraorbital foramen
    40 0→1 Separate left and right parietal ridges along entire length of parietal bone
    42 0→1 Dorsoventral position of ventral extent of anterior zygomatic root (relative to the cheek tooth row)
    60 0→1 Depth of masseteric fossa (mandible)
    62 2→3 Posterior extent of mandibular symphysis (mandible)
9 10 33 0→1 Lateral edge of palate emarginated from I1 to P3 in ventral view
    35 0→1 Median premaxillary process
    52 1→2 Postglenoid cavity / epitympanic fossa
    59 1→2 Forward extent of ectalveolar groove of mandible
    71 1→2 Humerus: deltoid tuberosity
8 11 13 0→1 M1 with decrease in enamel height on lingual surface at constriction or just posterior to this
 

brewerPhilippa Brewer
Department of Earth Sciences
Natural History Museum
London SW7 5BD
England
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Pip Brewer is Curator of Fossil Mammals at the Natural History Museum, London. She received her PhD in 2009 from the University of New South Wales, Australia. Prior to taking up her current role at the NHM in 2013, Pip worked at the British Museum and the Royal College of Surgeons of England. Her research interests include fossil vombatiforms and Mesozoic mammals.

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archerMichael Archer
School of Biological, Earth & Environmental Sciences
University of New South Wales
Sydney, 2052, New South Wales
Australia
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Michael Archer is Professor of Biological, Earth and Environmental Sciences at UNSW Australia. Research foci include the diversity and biostratigraphy of Mesozoic and Cenozoic fossil vertebrates, particularly mammals, from Australia and New Zealand, use of the fossil record to develop conservation strategies for living relatives, megafaunal extinctions, dental ontogeny and function and revitalizing ancient DNA.

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handSuzanne J. Hand
School of Biological, Earth & Environmental Sciences
University of New South Wales
Sydney 2052, New South Wales
Australia
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Suzanne J. Hand is Associate Professor in Biological, Earth and Environmental Sciences at UNSW Australia. As a vertebrate palaeontologist and morphologist, she has published widely on the origins, systematics and evolutionary history of Australia’s native fauna, the implications of continuing climatic and environmental change in Australia and the South Pacific, biocorrelation, and the global relationships, evolutionary ecology and biogeography of mammals, especially bats.

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abelRichard Abel
Faculty of Medicine
Department of Surgery & Cancer
Imperial College London
London SW7 2AZ
England
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Richie Abel is a lecturer in musculoskeletal anatomy at Imperial College London. He obtained degrees in Zoology (BSc) and Palaeontology (MSc) before completing a PhD. His thesis examined bone growth and development in the primate pelvis. The study adopted micro-CT and geometric morphometrics to compare relative levels of plasticity and constraint. Comparisons were made across tissues (cortical and trabecular) as well as species (modern humans, chimpanzees, gorillas and monkeys). Richie is interested in studying bone quality, with particular regard to tissue development and senescence. The general aim is to improve the diagnosis and measurement of treatment outcomes for of metabolic bone diseases.

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