TABLE 1. Dental measurements (in mm) of the m3 of Pseudotomus and Manitsha. Mean values for other taxa were derived from Wood (1962) and Storer (1988). Abbreviations: L, anteroposterior length; aW, transverse width of anterior portion of tooth; pW, transverse width of posterior portion of tooth.

  L aW pW aW / L
JODA 8900, Pseudotomus sp. 9.35 8.92 7.82 0.954
P. californicus (Wood, 1962) 7.03 5.64 5.45 0.802
P. horribilis (Wood, 1962) 5.93 5.34 5.30 0.901
P. littoralis (Wood, 1962) 6.6 5.2 5.0 0.788
P. petersoni (Wood, 1962) 6.26 5.65 5.26 0.903
P. robustus (Wood, 1962) 6.46 5.46 5.52 0.845
P. timmys (Storer, 1988) 9.9 9.2 7.7 0.929
Manitsha tanka (Wood, 1962) 9.37 8.50 7.83 0.907

 

 

TABLE 2. Dental measurements (in mm) of the holotype of Proischyromys perditus n. gen., n. sp. (UCMP 170698), as well as species of Ischyromys and Spurimus. Mean values for other taxa were derived from listed literature sources. Length of the tooth row (p4-m3L) was measured at the alveolar level. Abbreviations: L, anteroposterior length; W, transverse width.

  iL iW m1L m1W m2L m2W m3L m3W p4-m3L
Proischyromys perditus n. gen., n. sp. 4.03 1.88 3.01 - 2.98 3.06 3.04 2.81 12.30
Ischyromys typus (Wood, 1937) - - 3.69 3.41 3.68 3.53 3.99 3.32 14.36
I. blacki (Wood, 1974) ~4.6 - - - 2.94 3.36 3.56 3.20 13.0
I. douglassi (Black, 1968) - - 3.65 3.61 3.71 3.82 3.84 3.81 15.6
I. junctus (Russell, 1972) - - - - 2.94 3.03 3.40 3.00 -
I. parvidens (Wood, 1937) - - 2.97 2.64 2.77 2.91 3.38 2.81 12.16
I. pliacus (Wood, 1937) - - 3.76 3.89 3.89 3.97 4.1 3.6 16.4
I. veterior (Wood, 1974) 3.23 1.74 3.47 3.21 3.57 3.48 2.98 2.72 14.4
Spurimus scottii (Black, 1971) - - 2.18 1.95 - - - 2 -
S. selbyi (Black, 1971) - - 2.23 2.11 - - 2.3 2 -

 

TABLE 3. Comparison of some Eocene rodent faunas from Oregon and California.

Fauna Taxa Age
Friars Fm., California Microparamys minutus
Microparamys woodi
Pseudotomus californicus
Pseudotomus littoralis
?Uintaparamys caryophilus
Uriscus californicus
Sciuravus powayensis
Pareumys granger Metanoiamys agorus
Early Uintan (Ui1)
Santiago Fm., California Eohaplomys serus
Eohaplomys tradux

Microparamys minutus
Microparamys tricus
Microparamys woodi
Pseudotomus sp.
Rapamys fricki
Sciuravus powayensis
Metanoiamys agorus
Griphomys alecer
Uintan (Ui2 - Ui3)
Brea Canyon Local Fauna, Sespe Fm., California Eohaplomys matutinus
Eohaplomys serus
Eohaplomys tradux
Mytonomys burkei
Metaparamys compressidens
Rapamys fricki
Reithroparamys sp.
Tapomys tapensis
Uintaparamys leptodus
?Uintaparamys caryophilus
Pareumys milleri
Metanoiamys marinus
Griphomys alecer
Late Uintan (Ui3)
Hancock Quarry, Clarno Fm., Oregon Rodentia incertae sedis Late Uintan (Ui3) or Duchesnean
Whitecap Knoll, John Day Fm., Oregon Pseudotomus sp. Duchesnean
Pearson Ranch Local Fauna, Sespe Fm., California Microparamys tricus
Microparamys woodi
Uintaparamys sp.
Pareumys milleri
Presbymys lophatus
Griphomys alecer
Duchesnean
Simi Valley Landfill Local Fauna, Sespe Fm., California Simimys landeri
Simimys simplex
?Simiacritomys whistleri
Metanoiamys korthi
Paradjidaumo reynoldsi
Heliscomys walshi
Duchesnean
Upper Conglomerate Member,

 

Pomerado Conglomerate, California

Ischyromys sp.
Metanoiamys sp.
Protadjidaumo sp.
cf. Paradjidaumo sp.
cf. Griphomys sp.
Heliscomys sp.
Nonomys gutzleri
Unnamed Nonomyinae
Late Duchesnean or Early Chadronian (Ch1)
Lost Creek, John Day Fm., Oregon Proischyromys perditus n. gen., n. sp. Chadronian (Ch2 or later)