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Mammals from the earliest Uintan (middle Eocene) Turtle Bluff Member, Bridger Formation, southwestern Wyoming, Part 1: Primates and Rodentia

Thomas S. Kelly and Paul C. Murphey

Plain Language Abstract

In the type area of the Bridger Basin, the middle Eocene Bridger Formation is divided into three members; the Blacks Fork Member (lower Bridger), the Twin Buttes Member (upper Bridger), and Turtle Bluff Member (uppermost Bridger). For over a 100 years, the Turtle Bluff Member (TBM) had yielded only a few fragmentary specimens. As the result of many years of field work, numerous mammal fossils have now been recovered from the TBM, including marsupials, 'insectivores,' primates, rodents, artiodactyls, perissodactyls (a large rhino-like brontothere, a small rhinocerotoid, and a primitive horse), and an uintathere (primitive large ungulate). Many of these specimens have been included in published faunal lists, but, except for a new species of Tarsier-like primate (Hemiacodon engardae), they have never been formally described or illustrated. In this paper, we provide detailed systematic accounts of the primates and rodents from the TBM. A complete understanding of the faunal composition from the Turtle Bluff Member is important because it has been designated as the stratotype section for the earliest Uintan (biochron Ui1a) North American Land Mammal age. Except for H. engardae, all the primates from the TBM are holdover taxa from the earlier Bridgerian Land Mammal age, whereas the rodents exhibit a modest diversification during the earliest Uintan. The rodents Elymys? emryi new species and four informal species (Microparamys sp., sciuravid sp. A, cf. Pareumys sp., and Metanoiamys sp.) make their appearances in the TBM and, as such, can be added to the list of index species characterizing biochron Ui1a.

Resumen en Español

Mamíferos del Uintano temprano (Eoceno medio) del Miembro Turtle Bluff, Formación Bridger, sudoeste de Wyoming, Parte 1: Primates y Rodentia

El Miembro Turtle Bluff (MTB) es la sección estratotipo del biocrón más temprano del Uintano, Ui1a, de la Edad Mamífero norteamericana Uintano del Eoceno medio. Por más de un siglo, se han extraído del MTB únicamente unos pocos especímenes fragmentarios. Como resultado de muchos años de trabajo de campo, recientemente se han hallado numerosos fósiles de mamíferos que proveen una oportunidad sin precedentes de definir mejor este intervalo pobremente conocido. Esta es la primera de una serie de publicaciones que proveen descripciones detalladas y revisiones taxonómicas de la fauna del MTB. Aquí documentamos la ocurrencia de los siguientes taxones en el MTB: Uintasorex parvulus; Microsyops annectans; Notharctus robustior; Omomys carteri; Trogolemur myodes; Washakius insignis; Thisbemys corrugatus, Microparamys minutus; Microparamys sp.; Sciuravus nitidus; Tillomys senex; Tillomys? parvidens; Taxymys lucaris; Pauromys sp., cf. P. perditus; tres especies informales de sciurávidos (sp. A, B y C); cf. Pareumys sp.; Metanoiamys sp.; y Elymys? emryi especie nueva. Excepto por el previamente descripto Hemiacodon engardae, todos los primates del MTB son taxones remanentes de la Edad Mamífero Bridgeriano mientras que los roedores exhiben una modesta diversificación durante el Uintano más temprano. Elymys? emryi y cuatro especies informales de roedores adicionales (Microparamys sp., sciurávido sp. A, cf. Pareumys sp., y Metanoiamys sp.) aparecen en el MTB y, por ende, pueden ser agregadas a la lista de especies guía que caracterizan al biocrón Ui1a.

Palabras clave: bioestratigrafía; Eoceno; mamíferos; especie nueva; Uintano

Traducción: Diana Elizabeth Fernández

Résumé en Français

Mammifères de l'Uintien basal (Éocène moyen) du membre Turtle Bluff, formation de Bridger, sud-ouest du Wyoming, 1ère partie : Primates et Rodentia

Le membre Turtle Bluff (TBM) est la section stratotype du plus ancien biochrone de l'Uintien basal, Ui1a, dans l'Éocène moyen de l'âge uintien de l'échelle chronostratigraphique des mammifères terrestres d'Amérique du Nord (NALMA). Pendant plus d'un siècle, le TBM n'a livré que quelques spécimens fragmentaires. De nombreuses années de terrain ont abouti à la découverte de nombreux fossiles de mammifères et fournissent la possibilité inédite de mieux définir cet intervalle de temps mal connu. Ce papier est le premier d'une série de papiers qui fournit des descriptions détaillées et des révisions taxinomiques de la faune du TBM. Nous documentons ici l'occurrence des taxons suivants dans le TBM : Uintasorex parvulus ; Microsyops annectans ; Notharctus robustior ; Omomys carteri ; Trogolemur myodes ; Washakius insignis ; Thisbemys corrugatus ; Microparamys minutus ; Microparamys sp. ; Sciuravus nitidus ; Tillomys senex ; Tillomys? parvidens ; Taxymys lucaris ; Pauromys sp. ; cf. P. perditus ; trois espèces non nommées de sciuravidés (sp. A, B et C) ; cf. Pareumys sp. ; Metanoiamys sp. ; et Elymys? emryi sp. nov. À l'exception de l'espèce Hemiacodon engardae, précédemment décrite, tous les primates du TBM sont des taxons vestiges des dépôts plus anciens de l'âge Bridgérien de l'échelle chronostratigraphique des mammifères terrestres d'Amérique du Nord, alors que les rongeurs montrent une diversification modérée pendant l'Uintien basal. Elymys? emryi sp. nov. et quatre espèces supplémentaires non nommées de rongeurs (Microparamys sp., sciuravidé sp. A, cf. Pareumys sp., et Metanoiamys sp.) font leur apparition dans le TBM, et peuvent donc être ajoutées à la liste des espèces marqueurs caractérisant le biochrone Ui1a.

Mots-clés : biostratigraphie ; Éocène ; mammifères ; nouvelle espèce ; Uintien

Translator: Antoine Souron

Deutsche Zusammenfassung

Säugetiere aus dem Turtle Bluff Member (frühestes Uintium, mittleres Eozän), Bridger Formation, südwestliches Wyoming, Teil 1: Primaten und Rodentia

Das Turtle Bluff Member (TBM) ist die Stratotyp-Sektion für das früheste Uintium Biochron, Uila, der mitteleozänen Uintium Nordamerikanischen Landsäugetier Stufe. Die TBM hat für mehr als ein Jahrhundert nur fragmentarische Stücke hervorgebracht. In mehreren Jahren Feldarbeit wurden nun viele Fossilien entdeckt, die eine beispiellose Möglichkeit zu einer besseren Definition dieser wenig bekannten Zeitspanne bieten. Dies ist die erste Veröffentlichung einer Serie, die detaillierte Beschreibungen und taxonomische Revisionen der TBM-Fauna liefert. Hier dokumentieren wir das Vorkommen folgender Taxa in der TBM: Uintasorex parvulus; Microsyops annectans; Notharctus robustior; Omomys carteri; Trogolemur myodes; Washakius insignis; Thisbemys corrugatus, Microparamys minutus; Microparamys sp.; Sciuravus nitidus; Tillomys senex; Tillomys? parvidens; Taxymys lucaris; Pauromys sp., cf. P. perditus; drei informelle Sciuraviden-Arten (sp. A, B und C); cf. Pareumys sp.; Metanoiamys sp.; und Elymys? emryi neue Art. Außer des vorher beschriebenen Hemiacodon engardae, sind alle Primaten aus der TBM Überbleibsel aus der frühen Bridgerium-Landsäugetier-Stufe, wohingegen die Nagetiere eine geringe Diversifikation während des frühesten Uintium zeigen. Elymys? emryi und vier zusätzliche informelle Nagetierarten (Microparamys sp., sciuravid sp. A, cf. Pareumys sp., und Metanoiamys sp.) tauchen in der TBM auf und können als solche zur Liste der Indexarten, die die Biochrone Uila charakterisieren hinzugefügt werden.

Schlüsselwörter: Biostratigraphie; Eozän; Säugetiere; neue Arten; Uintium

Translator: Eva Gebauer

Arabic

Translator: Ashraf M.T. Elewa

 

 

TABLE 1. Measurements (in mm) of Primates from TBM (b = broken dimension, p. = partial).

Taxon/Specimen Number Position ap tr tra trp
Uintasorex parvulus          
SDSNH 110359 p. M2 1.18b 1.41b - -
SDSNH 110358 dp4 1.08 - 0.52 0.64
DMNH 75287 m2 1.14 - 0.83 0.88
Microsyops annectans          
UCM 67984 m1 4.59 - 3.50 3.67
UCM 70315 m2 5.05 - 3.53 3.91
Omomys carteri          
SDSNH 110357 M3 2.35 3.55 - -
UCM 68564 p4 2.58 1.78 - -
SDSNH 110355 m2 2.31b - 1.60b 1.80b
DMNH 75326 m3 2.69 - 1.62 1.54
UCM 95772 m3 2.90 - 1.80 1.75
Washakius insignis          
UCM 68541 M1 or 2 2.60 3.41 - -
Trogolemur myodes          
UCM 78097 m2 1.67 - 1.44 1.49
UCM 67883 m3 2.13 - 1.30 1.26
Notharctus robustior          
DMNH 75300 M1 7.06 8.57 - -
UCM 78457 p. M1 or 2 - 8.10b - -
UCM 69054 M3 5.00 6.50b    
UCM 72600 p3 4.17 3.14 - -
UCM 72600 p. p4 5.15b 4.36 - -

 

TABLE 2. Measurements (in mm) of Ischyromyidae and Rodentia, family undetermined from TBM (* = probably associated teeth).

Taxon/Specimen Number Position ap tr tra trp
Microparamys minutus          
UCM 66310 dP4 1.15 1.26 - -
UCM 95696 P4 1.16 1.28 - -
SDSNH 110373 dp4 1.23 - 0.75 0.90
SDSNH 110374 p4 1.18 - 0.82 1.06
SDSNH 110375 m1 or 2 1.31 - 1.16 1.17
DMNH 74140 m1 or 2 1.35 - 1.18 1.36
Microparamys sp.          
SDSNH 110395 dP4 1.26 1.40 - -
SDSNH 110360 p4* 1.36 - 0.93 1.16
SDSNH 110361 m1* 1.41 - 1.23 1.41
SDSNH 110362 m2* 1.49 - 1.44 1.50
Thisbemys corrugatus          
UCM 70671 m1 4.04 - 3.76 3.90
Rodentia, family undet.          
UCM 95700 m1 or 2 1.54 - 1.18 1.20

 

TABLE 3. Comparison of P4/p4 ap reduction in size (in percent) relative to M1/m1-2 aps in sciuravids and 'Microparamys' scopaiodon (* = percentages for means of isolated teeth that can only be identified as M1 or 2 and m1 or 2, ** = percentage based on alveolar ap of p4 or m1). References: 1 Bown (1982); 2 Burke (1937); 3 Dawson (1962); 4 Dawson (1966); 5 Dawson (1968); 6 Emry and Korth (1989); 7 Flanagan (1986); 8 Gazin (1952); 9 Gazin (1961); 10 Guthrie (1971); 11 Ivy (1990); 12 Korth (1984); 13 Korth (1994); 14 Loomis (1907); 15 Marsh (1871); 16 Marsh (1872); 17 Nelson (1974); 18 Peterson (1919); 19 Rasmussen et al. (1999); 20 Troxell (1923a); 21 Walsh (1997); 22 Walton (1993); 23 Walton and Porter (2008); 24 West (1973); 25 Wilson (1938a); 26 Wilson (1938b); 27 Wilson (1938c); 28 Wilson (1940); 29 Wood (1959b); 30 Wood (1962); 31 Wood (1965).

Taxon P4 ap/M1 ap p4 ap/m1 ap p4 ap/m2 ap References
Knightomys huerfanensis 95%* 80% 81% 12, 30
Knightomys minor 83% 90%* 85%* 11, 31
Knightomys senior - 93% 90% 8, 9, 11
Knightomys reginensis 85% - - 7, 12
Knightomys cuspidatus 77% 74% 72% 1, 12
Knightomys depressus 93% 87% 82% 8, 11, 14, 30, 31
Knightomys cremneus - 79% 79-85% 11, 23
Sciuravus wilsoni - 95% 90% 9, 30
Sciuravus nitidus 85% 84-93% 74-87% 15, 24
'Sciuravus' bridgeri - 93% 88% 26
Sciuravus eucristadens 79% 87.50% 79% 2, 5
Sciuravus powayensis 70% 82% 78-82% 21, 28
Sciuravus altidens 87% - - 18
Sciuravid sp. Powder Wash 91%* 88%* - 5
Sciuravid sp. Br3 79% - - 3
Sciuravus popi 79% - - 5, 19
'Sciuravus' rarus - 59% - 25
'Microparamys' scopaidon - ~65%** 3% 12, 13, 22
'Pauromys' schaubi - ~75% ~80%** 21, 29
Pauromys perditus - 56% 56% 5, 20
Pauromys lillegraveni 57% 50% 56% 22
Pauromys exallos - 101% 92% 6, 21
Pauromys sp. Powder Wash - 59% - 4, 22
Pauromys sp. Lost Cabin - 85% 76% 12
Taxymys lucaris 84% - - 16, 27
Tillomys senex - ~75%** - 16, 27
Tillomys? sp. Fowkes 74% 97% - 17

 

TABLE 4. Measurements (in mm) of specimens of Sciuravus, Taxymys , Tillomys, Pauromys sp., cf. P. perditus, sciuravid sp. B, sciuravid sp. C and Sciuravidae, genus and species undetermined from TBM (a = approximate; p. = partial).

Taxon/Specimen Number Position ap tra trp
Sciuravus nitidus        
UCM 68430 p. P4 1.97 2.42 2.28a
Taxymys lucaris        
UCM 68307 M1 or 2 1.97 1.97 2.13
UCM 95759 M1 or 2 1.87 1.87 1.70
UCM 95762 M1 or 2 1.90 2.05 1.87
UCM 68924 M1 or 2 1.82 1.82 1.92
UCM 68921 p. M3 1.72 1.77 -
DMNH 75336 M3 1.77 1.80 1.41
Tillomys senex        
SDSNH 110363 m1 or 2 1.96 1.82 1.92
DMNH 75279 m1 or 2 1.96 1.67 1.88
DMNH 75328 m1 or 2 2.05 1.80 1.97
UCM 78451 m1 or 2 1.92 1.57 1.72
UCM 95753 m1 or 2 1.95 1.54 1.69
Tillomys? parvidens        
SDSNH 110379 m1 or 2 1.87 1.50 1.64
DMNH 75329 m1 or 2 1.82 1.30 1.51
UCM 68533 p. m1 or 2 1.74 - -
DMNH 75288 m3 1.81 1.51 1.46
Pauromys sp., cf. P. perditus        
SDSNH 110414 m1 1.00 0.72 0.82
Sciuravid sp. B        
SDSNH 110412 M1 or 2 1.06 1.05 1.08
Sciuravid sp. C        
UCM 68672 M1 or 2 1.13 1.23 1.18
SDSNH 110447 M1 or 2 1.12 1.23 1.13
SDSNH 110443 M1 or 2 1.13 1.26 1.10
SDSNH 110439 m3 1.16 0.95 0.87
SDSNH 110441 m3 1.16 1.02 0.93
Sciuravidae, gen. and sp. undet.        
SDSNH 110462 P4 0.77 1.00 0.95
SDSNH 140176 p. p4 0.67 - 0.55
SDSNH 110454 p. p4 - - 0.80

 

TABLE 5. Measurements (in mm) of Sciuravid sp. A from TBM (p. = partial).

Specimen Number Position ap tra trp
UCM 68425 M1 or 2 1.25 - 1.13
UCM 70910 M1 or 2 1.28 1.35 1.23
UCM 71413 M1 or 2 1.33 1.26 1.13
UCM 95763 M1 or 2 1.29 1.23 1.10
UCM 95692 M1 or 2 1.28 1.33 1.25
UCM 95696 M1 or 2 1.28 1.34 1.28
UCM 95694 m1 1.23 0.90 1.00
UCM 95812 p. m1 1.21 - 1.00
SDSNH 110398 p. m1 1.18 - -
UCM 71414 m1 1.26 1.00 1.05
UCM 68969 m2 1.36 1.06 1.13
UCM 71415 m2 1.28 1.03 1.10
UCM 77428 m2 1.28 1.03 1.21
UCM 95754 m2 1.34 1.05 1.19
UCM 95755 m2 1.36 1.18 1.26
UCM 95757 m2 1.30 1.10 1.13
UCM 95698 m2 1.31 1.18 1.26
UCM 95699 m2 1.26 1.08 1.17
SDSNH 110458 m2 1.22 1.08 1.08
SDSNH 110459 m2 1.21 1.07 1.10
SDSNH 110460 m2 1.23 1.04 1.10
UCM 71516 m3 1.39 1.08 1.06
UCM 95752 m3 1.43 1.01 1.04
UCM 95756 m3 1.46 1.14 1.11
SDSNH 110440 m3 1.28 1.00 0.95

 

TABLE 6. Dental measurements (in mm) and dental ratios of unworn to early wear teeth of cf. Pareumys sp. from the TBM (a = approximate, pch = protocone or protoconid height of unworn teeth1 or teeth in early wear stage2; p. = partial).

Specimen Number Position ap tra trp pch pch/ap pch/tra
UCM 95760 P4 1.48 1.69 1.64 1.142 0.86 0.85
DMNH 75335 P4 1.36 1.76 1.72 - - -
DMNH 75337 P4 1.35 1.77 1.69 - - -
SDSNH 110435 p. P4 1.49 - - - - -
UCM 68942 M1 or 2 1.67 1.82 1.74 1.511 0.90 0.83
UCM 95758 M1 or 2 1.51 1.79 1.67 - - -
DMNH 75334 M1 or 2 1.51 1.53 1.43 1.301 0.86 0.85
SDSNH 110396 M1 or 2 1.69 1.86 1.79 1.641 0.97 0.88
SDSNH 110397 M1 or 2 1.71 1.85a 1.67 -   -
UCM 67987 M3 1.51 1.67 1.31 - - -
UCM 70905 M3 1.57 1.56 1.46 1.261 0.80 0.81
UCM 69974 m1 1.56 1.39 1.36 - - -
UCM 67885 m2 1.61 1.39 1.44 - - -
SDSNH 110366 m2 1.64 1.54 1.58 - - -
SDSNH 110365 m2 1.57a - 1.49 - - -
SDSNH 110367 m3 1.97 1.46 1.51 - - -
SDSNH 110368 p. m3 1.77a - - - - -
SDSNH 110434 m3 1.77 1.54 1.57 1.472 0.83 0.96

 

 

TABLE 7. Dental measurements (in mm) and statistics for Metanoiamys sp. from TBM.

Position   N Mean Observed range SD CV
dP4 ap 3 0.97 0.93-1.00 0.04 -
  tra 3 0.81 0.79-0.82 0.02 -
  trp 3 0.81 0.77-0.85 0.04 -
P4 ap 3 0.83 0.77-0.89 0.06 -
  tra 3 0.88 0.80-1.00 0.09 -
  trp 3 0.84 0.77-0.93 0.07 -
M1 or 2 ap 14 1.02 0.90-1.09 0.05 4.9
  tra 13 1.03 0.95-1.10 0.05 4.8
  trp 13 1.01 0.89-1.09 0.06 5.9
M3 ap 6 0.89 0.83-0.93 0.05 5.6
  tra 6 0.94 0.83-1.00 0.06 6.3
  trp 6 0.79 0.77-0.82 0.03 3.7
dp4 ap 1 0.80 - - -
  tra 1 0.49 - - -
  trp 1 0.70 - - -
p4 ap 6 0.86 0.79-0.93 0.06 6.5
  tra 6 0.67 0.58-0.70 0.03 4.6
  trp 6 0.79 0.70-0.84 0.04 5.1
m1 or 2 ap 10 1.00 0.89-1.07 0.06 6.0
  tra 10 0.88 0.80-1.00 0.07 7.9
  trp 10 0.94 0.82-1.04 0.08 8.5
m3 ap 4 1.05 1.00-1.08 0.04 -
  tra 4 0.92 0.85-0.98 0.06 -
  trp 4 0.85 0.79-0.93 0.06 -

 

TABLE 8. Measurements (in mm) of SDSNH specimens of Elymys ? emryi new species from TBM (a = approximate, enamel abraded; p. = partial).

Specimen Number Position ap tra trp
110466 (holotype) M1 1.17 0.95 0.95
110465 M1 1.18 0.96 0.96
110463 M1 1.20 1.07 1.15
110464 p. M1 1.18 - 1.13
110444 M2 1.21 1.10 1.10
110448 M3 0.98 1.00 0.82
110455 m1 1.23 0.54 0.89
110456 m1 1.16 0.52 0.81
110405 m2 1.18a 0.92a 0.90a
110457 m2 1.28 0.98 1.05
110461 m3 1.21 1.00 0.82

 

TABLE 9. Comparison of lower molar characters of UCM 95700, Ailuravus michauxi, Eohaplomys, Haplomys and Spurimus scotti (presumed shared characters in bold; character states after Rensberger [1975] and Korth [1988]).

Character UCM 95700 Ailuravus Eohaplomys Haplomys Spurimus
1. angle between labial and posterior margins nearly square - 790-850 more acute - 600 -730 on m1-2, nearly square on m3 nearly square - 790-850 more acute - 600-730 more acute - 600-730
2. trigonids proportions Relatively wide trigonid basin with longer metalophulids I and II Relatively wide trigonid basin with longer metalophulids I and II Relatively wide trigonid basin with longer metalophulids I and II, especially in m3 trigonid basins narrower with shorter metalophulid I and II, especially m3 trigonid basins narrower with shorter metalophulid I and II, especially m3
3. metastylid crest Strongly developed Strongly developed Strongly developed More weakly developed More weakly developed
4. metastylid Absent Absent Absent or sometimes incipient on posterior edge of metastylid crest Present - well developed Absent
5. entoconid Bulbous Bulbous Bulbous Not bulbous, more anteroposteriorly compressed Not bulbous, more anteroposteriorly compressed
6. hypolophid and hypolophid connection Incomplete, extending into central basin with no connection Usually incomplete, extending into central basin, especially m3, or sometimes connecting to posterior cingulid Commonly complete, but low labially, connects to mesoconid Complete, tall and usually connects to posterior corner of ectolophid Complete, tall and usually connects to posterior corner of ectolophid
7. mesoconid small - oval shaped Commonly present - usually oval shaped Present - oval shaped More triangularly shaped with labial crest Absent
8. ectolophid straight Relatively straight Relatively straight Inflected Inflected
9. space (or valley) between entoconid, hypolophid and posterior cingulid Wide Wide Wide Narrow Narrow
10. crenulated enamel Yes Yes Yes No No
 

FIGURE 1. Map of study area showing modern and historical geographic terminology along with geographic position of type section of Turtle Bluff Member, Bridger Formation (modified after Murphey [2001]). The light purple shading represents areas on the lower slopes of the principal mountain landforms and the green shading represents areas above the base of the uppermost slopes for each landform (approximate elevations in feet are shown). Insert map shows location of study area in state of Wyoming.

figure1

FIGURE 2. Schematic stratigraphic column of type section of Turtle Bluff Member on southwest flank of Cedar Mountain, Bridger Formation, showing relative stratigraphic positions of SDSNH, DMNH and UCM localities (along with the locality names in parentheses) that yielded the fossils described in this paper (modified and corrected after Gunnell et al., [2009]). Locality MPM 2970 occurs on southwest flank of Sage Creek Mountain and its approximate relative stratigraphic position is projected onto type section. Abbreviations are: Lithostr., lithostratigraphic; NALMA, North American Land Mammal age.

figure2

FIGURE 3. Microsyopidae from TBM. 1-4, Uintasorex parvulus: 1, RM1 or 2, SDSNH 110359; 2-3, Rdp4, SDSNH 110358; 4, Lm2, DMNH 75287. 5-7, Microsyops annectans: 5, Rm1, UCM 68541; 6-7, partial dentary with Rm2, UCM 70315. 1-2, 4-6, occlusal views. 3 and 7, labial views. Scale bars equal 1 mm for 1-6 and scale bar for 7 equals 5 mm.

figure3

FIGURE 4. Primates from TBM. 1-3, Notharctus robustior: 1, RM1, DMNH 75300; partial RM1 or 2, UCM 78457; 3, partial RM3, UCM 69054. 4-5, Trogolemur myodes: 4, Rm2, UCM 78097; 5, Rm3, UCM 67883. 6, Washakius insignis, LM1 or 2, UCM 68541. 7-9, Omomys carteri: 7, LM3, 110357; 8, Lm1, SDSNH 110355; 9, Rm3, DMNH 75326. All occlusal views. Scale bar equals 1 mm.

figure4

FIGURE 5. Microparamys from TBM. 1-5, Microparamys minutus : 1, LdP4, UCM 66310; 2, LP4, UCM 95695; 3, LM1 or 2, UCM 95697; 4, Rp4, SDSNH 110374; 5, Lm1 or 2, DMNH 74140. 6-9, Microparamys sp.: 6, LdP4, SDSNH 110395; 7, Lp4, SDSNH 110360; 8, Lm1, SDSNH 110361; 9, Lm2, SDSNH 110362. All occlusal views. Scale bar equals 1 mm.

figure5

FIGURE 6. Thisbemys and Rodentia, family undetermined from TBM. 1, Thisbemys corrugatus, Rm1, UCM 70671. 2-3, Rodentia, family undetermined, Rm1 or 2, UCM 95700. 1-2, occlusal views. 3, oblique labial view. Scale bar equals 1 mm.

figure6

FIGURE 7. Larger Sciuravidae from TBM. 1, Sciuravus nitidus, RP4, UCM 68430. 2-4, Taxymys lucaris: 2, RM1 or 2, UCM 68307; 3, LM1 or 2, UCM 95762; 4, LM3, DMNH 75336. 5-7, Tillomys senex: 5, Lm1 or 2, DMNH 75328; 6, Rm1 or 2, DMNH 75279; 7, Rm1 or 2, SDSNH 110363. 8-9, Tillomys ? parvidens: 8, Rm1 or 2, SDSNH 110379; 9, Lm3, DMNH 75288. All occlusal views. Scale bar equals 1 mm.

figure7

FIGURE 8. Smaller Sciuravidae from TBM. 1, Pauromys sp., cf. P. perditus , Lm1, SDSNH 110414. 2, sciuravid sp. B, RM1 or 2, SDSNH 110412. 3-4, sciuravid sp. C: 3, RM1 or 2, SDSNH 110443; 4, Lm3, SDSNH 110441. 5-7, sciuravid premolars: 5, LP4, SDSNH 110462; 6, partial Rp4, SDSNH 110454; 7, partial Rp4, SDSNH 140176. All occlusal views. Scale bar equals 1 mm.

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FIGURE 9. Sciuravid sp. A from TBM: 1, RM1 or 2, UCM 709102; 2, RM1 or 2, UCM 68903; 3, LM1 or 2, UCM 71413; 4, LM1 or 2, UCM 95763; 5, Rm1, UCM 95694; 6, Lm1 or 2, UCM 95757; 7, Rm1 or 2, SDSNH 110459; 8, Rm1 or 2, UCM 95699; 9, Lm3, UCM 95756. All occlusal views. Scale bar equals 1 mm.

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FIGURE 10. cf. Pareumys sp. from TBM: 1, RP4, UCM 95760; 2-3, RM1 or 2, SDSNH 110396; 4, RM1 or 2, SDSNH 110397; 5, RM1 or 2, DMNH 75334; 6, LM1 or 2, UCM 95758; 7, LM3, UCM 67987; 8, Rm1, UCM 69974; 9, Lm2, SDSNH 110366; 10, Rm3, SDSNH 110367; 11-12, Rm3, SDSNH 110434. 1-2, 4-11 occlusal views. 3, anterior view. 12, labial view. Scale bar equals 1 mm.

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FIGURE 11. Metanoiamys sp. from TBM: 1, LdP4, DMNH 74135; 2, LP4, DMNH 75331; 3, LM1 or 2, DMNH 74136; 4, LM1 or 2, DMNH 75251; 5, RM1 or 2, SDSNH 110442; 6, LM3, UCM 98813; 7, Rdp4, SDSNH 110369; 8, Lp4, DMNH 74143; 9, Lm1 or 2, DMNH 75252; 10, Lm1 or 2, DMNH 75250; 11, Lm1 or 2, DMNH 75254; 12, Lm3, DMNH 74144. All occlusal views. Scale bar equals 1 mm.

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FIGURE 12. Elymys ? emryi new species from TBM, macrophotographs with corresponding line drawings of specimens: 1 and 9, LM1, SDSNH 110463; 2 and 10, RM1, SDSNH 110465; 3 and 11, RM1 (holotype), SDSNH 110466; 4 and 12, RM2, SDSNH 110444; 5 and 13, LM3, SDSNH 110448; 6 and 14, Rm1, SDSNH 110456; 7 and 15, Lm2, SDSNH 110457; 8 and 16, Lm3, SDSNH 110461. All occlusal views. Scale bar equals 1 mm.

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author1Thomas S. Kelly. Research Associate, Vertebrate Paleontology Department, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, California 90007, USA, This email address is being protected from spambots. You need JavaScript enabled to view it.

Thomas Kelly received his B.A. and M.S. degrees in Biology from the California State University at Northridge (1968 and 1969) and a doctorate in Veterinary Medicine (DVM) from the University of California at Davis (1973). He did postgraduate research concentrating on the phylogenetic systematics of heteromyid rodents with Dr. Robert L. Rudd of the Department of Zoology, University of California, Davis in 1973-74. Since 1988, Dr. Kelly been a Research Associate in the Vertebrate Paleontology Department at the Natural History Museum of Los Angeles County and has been working as a consultant for paleontological resource impact mitigation projects in California for the last 25 years. He has published 46 paleontological articles, 35 of which were in peer-reviewed scientific journals. He has been the author or co-author of a number of new taxa in the paleontological literature, including nine mammal genera, 29 mammal species and one fish species. His interests are primarily in mammalian systematics and biostratigraphy.

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author2Paul C. Murphey. Research Associate, Department of Paleontology, San Diego Museum of Natural History, 1788 El Prado, San Diego, California 92101, USA, This email address is being protected from spambots. You need JavaScript enabled to view it.

Paul Murphey received a doctorate in geological sciences with an emphasis in vertebrate paleontology from the University of Colorado at Boulder in 2001. His professional experience includes appointments as the Collections Manager of Paleontology, Geology and Osteology in the Geology Section of the University of Colorado Museum; instructor in the Museum and Field Studies Program at the University of Colorado Museum; and graduate faculty member in the Department of Geological Sciences at the University of Colorado. He was an Associate Curator in the Department of Paleontology and the Associate Director of the Department of PaleoServices at the San Diego Natural History Museum. Dr. Murphey has been working as a consultant and Principal Investigator for paleontological resource impact mitigation projects throughout the United States for approximately 20 years. He was the Principal Paleontologist of the Paleontological Resources Program at SWCA Environmental Consultants for 11 years. In 2014, he joined Los Angeles–based Paleo Solutions as a partner and Vice President, forming Denver-based Rocky Mountain Paleo Solutions. Dr. Murphey is currently a research associate in the Department of Earth Sciences at the Denver Museum of Nature and Science and the Department of Paleontology at the San Diego Natural History Museum. His research is focused on the evolutionary history, stratigraphy, biochronology, and depositional environments of Paleogene fossil mammals and associated rock units in the Rocky Mountain region and southern California.

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