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Connecting Hunter-Schreger Band microstructure to enamel microwear features: New insights from durophagous carnivores

100%

Tseng Z. J.

Acta Palaeontologica Polonica

2012

tom 57

nr 3

Several recent studies have clarified the link between microwear features and diet among living carnivorans, but it is still unclear whether previously interpreted evolutionary trends for dietary specialization, based on examination of enamel microstructure, are consistent with such insights from microwear analysis. This study examined the relationship between microwear and microstructure features using a sample of fossil hyaenids and canids. Hunter−Schreger Bands (HSB) and microwear features were examined at the same magnification level using optical stereomicroscopy. Multiple trials conducted on each specimen showed higher variance of smaller (<0.03 mm) microwear features compared to large (>0.03 mm) features. The number of pits was positively correlated with more derived HSB in both p4 and m1; fossil teeth with derived HSB possessed microwear features similar to patterns found in modern spotted hyenas. Microscopic scratches were not as closely associated with HSB patterns, but large scratches were more tightly linked to HSB than smaller ones on p4. An examination of evolutionary trends in HSB specialization in the two carnivoran lineages showed that derived HSB patterns evolved prior to the highly robust craniodental characteristics typical of later bone−cracking ecomorphologies. Therefore, the increase of hard food in the diet of less specialized hyaenids and canids was accompanied by a mosaic mode of evolution, with microstructural changes preceding key macrostructural morphological adaptations.

A dental microwear texture analysis of the Mio-Pliocene hyaenids from Langebaanweg, South Africa

100%

Stynder D. D., Ungar P. S., Scott J. R., Schubert B. W.

Acta Palaeontologica Polonica

2012

tom 57

nr 3

Hyaenids reached their peak diversity during the Mio−Pliocene, when an array of carnivorous species emerged alongside dwindling civet−like and mongoose−like insectivorous/omnivorous taxa. Significantly, bone−cracking morphological adaptations were poorly developed in these newly−emerged species. This, their general canid−like morphology, and the absence/rarity of canids in Eurasia and Africa at the time, has led researchers to hypothesise that these carnivorous Mio−Pliocene hyaenas were ecological vicars to modern canids. To shed further light on their diets and foraging strategies, we examine and compare the dental microwear textures of Hyaenictitherium namaquensis, Ikelohyaena abronia, Chasmaporthetes australis, and Hyaenictis hendeyi from the South African Mio−Pliocene site of Langebaanweg with those of the extant feliforms Crocuta crocuta, Acinonyx jubatus, and Panthera leo (caniforms are not included because homologous wear facets are not directly comparable between the suborders). Sample sizes for individual fossil species are small, which limits confidence in assessments of variation between the extinct taxa; however, these Mio−Pliocene hyaenas exhibit surface complexity and textural fill volume values that are considerably lower than those exhibited by the living hyaena, Crocuta crocuta. Dental microwear texture analysis thus supports interpretations of craniodental evidence suggesting low bone consumption in carnivorous Mio−Pliocene hyaenas.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Schubert B. W.

1 Scott J. R.

1 Stynder D. D.

1 Tseng Z. J.

1 Ungar P. S.

2 2012

Wyniki wyszukiwania

Connecting Hunter-Schreger Band microstructure to enamel microwear features: New insights from durophagous carnivores

A dental microwear texture analysis of the Mio-Pliocene hyaenids from Langebaanweg, South Africa