Arctodus pristinus

[brobear]

www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/arctodus-pristinus/  
 

Arctodus pristinus
Quick Facts
Common Name: Lesser short-faced bear

Largest land canivore in Florida during the early Pleistocene.

Among living bears, most closely related to the spectacled bear of South America.

Age Range

Early to middle Pleistocene Epoch; Blancan and Irvingtonian land mammal ages
About 2.5 to 0.5 million years ago
Scientific Name and Classification
Arctodus pristinus Leidy, 1854

Source of Species Name: Leidy (1854) did not provide a reason for the species name, but pristinus in Latin means 'primitive' or 'early'. This name may have been given because Arctodus pristinus was the first Arctodus Leidy identified.

Classification: Mammalia, Eutheria, Laurasiatheria, Caniformia, Carnivora, Arctoidea, Ursoidea, Ursidae, Tremarctinae

Alternate Scientific Names: Ursus haplodon; Arctodus haplodon 
 

Overall Geographic Range
Arctodus pristinus, map
Figure 1. Map of Florida, with highlights indicating counties where fossils of this species have been found.

Eastern and possibly central United States, including occurrences in Florida, coastal South Carolina, Maryland, southeastern Pennsylvania, possibly Kansas (Kurtén, 1967; Emslie, 1995), and Central Mexico (Dalquest and Mooser, 1980). Ashley River, near Charleston, South Carolina, is the type locality.

Florida Fossil Occurrences
Florida fossil sites with Arctodus pristinus:

Alachua County—Haile 16A
Brevard County—Sebastian Canal 2
Charlotte County—Port Charlotte area (specific location unknown)
Citrus County—Crystal River Power Plant; Inglis 1A; Inglis 1B
Columbia County—Santa Fe River 1
Hillsborough County—Apollo Beach; Leisey Shell Pit 1; Leisey Shell Pit 1A; Leisey Shell Pit 3
Levy County—McLeod Limerock Mine
Okeechobee County—Kissimmee 6  
   

Sarasota County—Bass Point Waterway; Rigby Shell Pit; Venice Beach
Sumter County—Coleman 2A
Discussion
Arctodus pristinus is a large tremarctine bear. More fossils of this species are known from Florida (about 150) than anywhere else. Compared to the gigantic Arctodus simus, the premolars and first molars of Arctodus pristinus are relatively smaller and more widely spaced (Figs 2-5; Schubert et al., 2010). Both species show pronounced intraspecific variation, much of it related to sexual dimorphism, with smaller, more lightly built females and larger, massive males. Males of the smaller species A. pristinus overlap in size with females of A. simus.     
      

There is even greater overlap in size between A. pristinus and the late Pleistocene species Tremarctos floridanus. The molars of A. pristinus are, on average, broader and taller than those of Tremarctos floridanus, but these differences are quickly obscured by wear. Most published comparisons are between the two species of Arctodus, or between A. simus and T. floridanus, and not between the two more similar-sized A. pristinus and T. floridanus. Samples are now available to make such comparisons worthwhile. Although not completely satisfactory, in practice large tremarctine fossils from the early to early middle Pleistocene of Florida can be identified as A. pristinus, while those from the late Pleistocene are considered T. floridanus. Specimens of ambiguous age, unless they include molar teeth that are relatively complete and unworn or only slightly worn, will be very difficult to identify precisely.   
  

The genus Arctodus is generally regarded as being more carnivorous than either Tremarctos or the black bear Ursus americanus. Its large size would allow it to take carcasses away from most other carnivores, especially solitary felids. The bite marks found on many bones of sloths and young proboscideans at Leisey Shell Pit matched the size of the canine teeth of Arctodus pristinus (Pratt and Hulbert, 1995). It is not known if these bite marks are the result of active predation or scavenging.

[brobear]

shaggygod.proboards.com/board/12/americas

Of the two North American short-faced bear species, Arctodus pristinus is more primitive and could be ancestral to Arctodus simus. The lesser short-faced bear preferred moister, more heavily-wooded eastern coastal regions. Arctodus pristinus lived near the Atlantic coast and in Mexico from Kansan to Wisconsinan (about 800,000 to 10,000 years ago) time. With its relatively longer face, smaller, narrower teeth, and smaller stature, this bear may have been more omnivorous (eating plants as well as animals) than Arctodus simus. Perhaps the lesser short-faced bear died out through competition with a large Pleistocene subspecies of black bear (Ursus americanus amplidens), as well as brown bears invading from the west.

A. pristinus had longer, more slender limb bones than Tremarctos, and its muzzle was similarly short. The anterior premolars were small and well-spaced; the molars were smaller relative to jaw length than in A. simus (Kurten 1967). Height of the jaw articulation was quite variable, from high above the occlusal surface of the cheek teeth to only slightly higher (Emslie, in press). There are too few specimens to identify a representative norm. This variation is difficult to interpret without information on how it compares to variation in other ursids, particularly Tremarctos.

Fossils of A. pristinus have been found only in the southeastern corner of this continent (Fig. and possibly the lower mid-west (Kurten 1967; Kurten & Anderson 1980; Emslie, in press). A. pristinus occupied eastern North America until the Wisconsinan, with the most recent known survivors in Florida where it was sympatric with the spectacled bear, which survived into the Holocene.

Emslie, S.D., 1995, The fossil record of Arctodus pristinus (Ursidae:Tremarctinae) in Florida: Bulletin of the Florida Museum of Natural History, v. 37, p. 501-514.

Harington, C.R. 1973. A short-faced bear from ice age deposits at Lebret, Saskatchewan. Blue Jay 31(1):11-14.

Kurtén, B., 1967, Pleistocene bears of North America. 2. Genus Arctodus, short-faced bears: Acta Zoologica Fennica, v. 117, p. 1-58.

Kurtén, B., & Anderson, E., 1980, Pleistocene mammals of North America: Columbia University Press, New York, 442 p

Stringham, F. S, 1992. Evolution of Bears (manuscript).

[King Kodiak]

Arctodus pristinus is a large tremarctine bear. More fossils of this species are known from Florida (about 150) than anywhere else. Compared to the gigantic Arctodus simus, the premolars and first molars of Arctodus pristinus are relatively smaller and more widely spaced (Figs 2-5; Schubert et al., 2010). Both species show pronounced intraspecific variation, much of it related to sexual dimorphism, with smaller, more lightly built females and larger, massive males. Males of the smaller species A. pristinus overlap in size with females of A. simus.



Figure 2. Occlusal view of UF/TRO 15, a mandible Arctodus pristinus from Haile 16A. Tooth preserved on the left side are a broken canine, the small third and fourth premolars, and the large first and second molars. A portion of the root of the second premolar is also present.


Figure 3. Lateral view of UF/TRO 15, a left mandible of Arctodus pristinus from Haile 16A, Alachua County, Florida.
Arctodus pristinus, fig. 4
Figure 4. Medial view of the left mandible of Arctodus pristinus



Medial view of the left mandible.




www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/arctodus-pristinus/

[King Kodiak]

There is even greater overlap in size between A. pristinus and the late Pleistocene species Tremarctos floridanus. The molars of A. pristinus are, on average, broader and taller than those of Tremarctos floridanus, but these differences are quickly obscured by wear. Most published comparisons are between the two species of Arctodus, or between A. simus and T. floridanus, and not between the two more similar-sized A. pristinus and T. floridanus. Samples are now available to make such comparisons worthwhile. Although not completely satisfactory, in practice large tremarctine fossils from the early to early middle Pleistocene of Florida can be identified as A. pristinus, while those from the late Pleistocene are considered T. floridanus. Specimens of ambiguous age, unless they include molar teeth that are relatively complete and unworn or only slightly worn, will be very difficult to identify precisely.




5. UF 19398, partial skull of Arctodus pristinus from Inglis 1A, Citrus County, Florida. A, close up of right teeth (upper third incisor, canine, and second, third, and fourth premolars; B, close up of left teeth (upper canine, fourth premolar, and first molar).




Femur of Arctodus Pristinus

[brobear]

( quote ): Males of the smaller species A. pristinus overlap in size with females of A. simus.

*Never gave it any thought, but we can also say that the size of a male black bear overlaps with that of a female grizzly.

[King Kodiak]

Apr 25, 2019 2:27:19 GMT -5 brobear said:

( quote ): Males of the smaller species A. pristinus overlap in size with females of A. simus.

*Never gave it any thought, but we can also say that the size of a male black bear overlaps with that of a female grizzly.

Yeah exacly. I have found no mention anywhere of the probable weight of Arctodus Pristinus although its mentioned it had a similar size to Tremarctos floridanus, 150 to 300 Kg, (330 to 660 lbs).

Also, quote from above:

The genus Arctodus is generally regarded as being more carnivorous than either Tremarctos or the black bear Ursus americanus. Its large size would allow it to take carcasses away from most other carnivores, especially solitary felids. The bite marks found on many bones of sloths and young proboscideans at Leisey Shell Pit matched the size of the canine teeth of Arctodus pristinus (Pratt and Hulbert, 1995). It is not known if these bite marks are the result of active predation or scavenging.

[brobear]

An interesting encounter would be between a grizzly and A. pristinus.
I read ( a bit off topic ) that the arrival of the black bear was not good for the Florida spectacled bear. The black bear simply out-competed the larger bear. Some experts believe the same holds true for the grizzly and A. simus. Bears of the genus Ursus ( probably ) had a much wider range of food choices. Plus the ability to sleep through the Winter months.

[Deleted]

Apr 25, 2019 5:32:24 GMT -5 brobear said:

An interesting encounter would be between a grizzly and A. pristinus.
I read ( a bit off topic ) that the arrival of the black bear was not good for the Florida spectacled bear. The black bear simply out-competed the larger bear. Some experts believe the same holds true for the grizzly and A. simus. Bears of the genus Ursus ( probably ) had a much wider range of food choices. Plus the ability to sleep through the Winter months.

It seems jut as I predicted, the black bear is dominant over the spectacled bear. Lets hope the black bear doesn't migrate further down south and out compete the remaining spectacled bears.

[brobear]

Arctodus pristinus

Quick Facts
Common Name: Lesser short-faced bear

Largest land canivore in Florida during the early Pleistocene.

Among living bears, most closely related to the spectacled bear of South America.

Age Range

Early to middle Pleistocene Epoch; Blancan and Irvingtonian land mammal ages
About 2.5 to 0.5 million years ago 
  
Scientific Name and Classification
Arctodus pristinus Leidy, 1854

Source of Species Name: Leidy (1854) did not provide a reason for the species name, but pristinus in Latin means 'primitive' or 'early'. This name may have been given because Arctodus pristinus was the first Arctodus Leidy identified.

Classification: Mammalia, Eutheria, Laurasiatheria, Caniformia, Carnivora, Arctoidea, Ursoidea, Ursidae, Tremarctinae

Alternate Scientific Names: Ursus haplodon; Arctodus haplodon 
  
Overall Geographic Range:   
  
Eastern and possibly central United States, including occurrences in Florida, coastal South Carolina, Maryland, southeastern Pennsylvania, possibly Kansas (Kurtén, 1967; Emslie, 1995), and Central Mexico (Dalquest and Mooser, 1980). Ashley River, near Charleston, South Carolina, is the type locality.

Florida Fossil Occurrences
Florida fossil sites with Arctodus pristinus:

Alachua County—Haile 16A
Brevard County—Sebastian Canal 2
Charlotte County—Port Charlotte area (specific location unknown)
Citrus County—Crystal River Power Plant; Inglis 1A; Inglis 1B
Columbia County—Santa Fe River 1
Hillsborough County—Apollo Beach; Leisey Shell Pit 1; Leisey Shell Pit 1A; Leisey Shell Pit 3
Levy County—McLeod Limerock Mine
Okeechobee County—Kissimmee 6
Sarasota County—Bass Point Waterway; Rigby Shell Pit; Venice Beach
Sumter County—Coleman 2A

[brobear]

WORLD OF PREHISTORIC CREATURES
Arctodus pristinus mom and her cub.
by Roman Roman Yevseyev

[OldGreenGrolar]

/\ I am sure the Arctodus was a good mother.

[brobear]

Ancient Bears:

[brobear]

THEFOSSIIL RECORD OFARCTODUS PRLSTINUS
(URSIDAES TREMARCTINAE) IN FLORIDA

www.floridamuseum.ufl.edu/wp-content/uploads/sites/35/2017/03/Vol-37-No-15.pdf

CONCLUSIONS:

Arctodus pristinus is now known from 13 late Pliocene and early Pleistocene
localities in Florida. The sample from Leisey Shell Pit adds to the growing list of
records, and to our understanding of this species. A closely related species,
Tremarctosfloridanus, also is well-known from Florida from at least 19 sites (it is
incorrectly reported from Inglis lA and Withlacoochee River 7A by Webb [1974]
and Kurt6n and Anderson [1980]). All known-age specimens date to the late
Pleistocene (Rancholabrean) and do not coincide with the presence ofA. pristinus
within the state. It is possible that T. floridanus was an ecological replacement of
A. pristinus. Both species, as well as A. simus from western North America, were
probably largely herbivorous (Kurtdn 1966, 1967; Kurt6n and Anderson 1980;
Emslie and Czaplewski 1985), much like the extant spectacled bear, T. ornatus, in
South America (Peyton 1980). T. jloridanus is known however, from early
Irvingtonian and Blancan localities in western North America (Kurt6n and
Anderson 1980) and may yet be found in similar-aged sites in Florida
Material of Arctodus pristinus in Florida exhibits not only sexual
dimorphism, but also differences in morphologic features that probably represent
temporal and geographic variation. Considerable sexual variation was observed in
16 skeletons of T. omatus at USNM: males are usually larger and have a large
sagittal crest whereas females are smaller and have a reduced or no sagittal crest.
In addition, the features of the dentition can be quite variable, particularly the M2.
Study of these variations is needed prior to futther systematic work with fossil
tremarctines.