岡瓦那獸目

岡瓦那獸目 化石時期： 坎帕階-中新世, （可能在侏羅紀出現）
科學分類
界： 動物界 Animalia 門： 脊索動物門 Chordata 亞門： 脊椎動物亞門 Vertebrata 綱： 哺乳綱 Mammalia 目： 岡瓦那獸目 Gondwanatheria
科
?Allostaffia科 Sudamericidae科 Bharattherium Gondwanatherium Lavanify Patagonia Sudamerica Vintana Ferugliotheriidae科 Ferugliotherium Trapalcotherium (?) Argentodites †Groeberiidae科 †Groeberia ?†Klohnia ?†Epiklohnia ?†Praedens 未知的科 Greniodon

岡瓦那獸目（學名：Gondwanatheria，亦可稱為岡瓦納獸目）是哺乳動物中一個已經滅絕的目，生活在上白堊世至中新世（且可能更早，如果將Allostaffia劃為該目的成員）的南半球，包括南極洲。該類群為人所知的僅有數顆分離的牙齒，幾片下頜骨，兩塊不完整的頭骨和一個完整的頭蓋骨 。正是因為這種零碎的知識，其分類地位不甚清晰。

分類

Vintana sertichi的重建圖。除頭部外的身體部分為想象圖。

該類群分類關係的不明確持續了幾十年，其最開始被認為是早期的異關節總目動物，一種「無齒」的哺乳動物，接近現代的食蟻獸。隨後的多個不同研究認為它們屬於異獸亞綱，接近多瘤齒獸目，甚至可能真正屬於多瘤齒獸目，比Cimolodonta亞目更接近於Plagiaulacida亞目。However, a more recent study recovered them as nested among haramiyidans, rendering them as non-mammalian cynodonts.

There are three known families within Gondwanatheria. The family Sudamericidae was named by Scillato-Yané and Pascual in 1984, and includes the vast majority of named taxa. The family Ferugliotheriidae was named by José Bonaparte in 1986, and includes one genus, Ferugliotherium, and possibly a few other forms like Trapalcotherium. Groeberiidae, originally interpreted as paucituberculate marsupials, has since been understood as gondwanatherians, though only the type genus, Groeberia, has been examined as such.

Gondwanatheria cladogram per Chimento et al. 2015.

Further fossils have come from India, Madagascar and Antarctica. A possible Ferugliotherium-like species occurs in Maastrichtian deposits of Mexico, extending the clade to North America.

The Miocene (Colhuehuapian) genus Patagonia is the youngest known representative.

生物學

Gondwanatheres known from cranial remains almost universally have deep, robust snouts, as befitting their specialised herbivorous lifestyle. Groeberia and Vintana both possess bizarre jugal flanges similar to those of xenarthrans like ground sloths, though they had a palinal (front-to-back) chewing method as in most allotheres and unlike almost any therian. Most gondwanatheres are specialised grazers, even being among the first mammals to have specialised for grass-eating long before any therians did, with the exceptions of Groeberidae and Ferugliotheriidae, which lack hyopsodont teeth and therefore had more generalistic herbivorous habits.

An articulated specimen found in the Maevarano Formation offers insight to the postcranial skeleton of these animals. Among the bizarre and unique features are a mediolaterally compressed and antero-posteriorly bowed tibia, a double trochlea on the astragalus, a fully developed humeral trochlea, and an unusually high number of trunk vertebrae. The new taxon has at least 19 rib-bearing (thoracic) and 11 non-rib-bearing (lumbar) vertebrae. Aside from these derived features, the Malagasy mammal has a mosaic pectoral girdle morphology: the procoracoid is lost, the coracoid is extremely well developed (into an enlarged process that contributes to half of the glenoid fossa), the interclavicle is small, and the sternoclavicular joint appears mobile. A ventrally facing glenoid and the well-developed humeral trochlea suggest a relatively parasagittal posture for the forelimbs. Remarkable features of the hind limb and pelvic girdle include a large obturator foramen similar in size to that of therians, a large parafibula, and the presence of an epipubic bone.

分類

Order †Gondwanatheria McKenna 1971 [Gondwanatheroidea Krause & Bonaparte 1993]

• ?†Allostaffia
• Family †Groeberiidae Patterson, 1952
  • †Groeberia minoprioi Ryan Patterson, 1952
  • †Groeberia pattersoni G. G. Simpson, 1970
  • ?†Klohnia charrieri Flynn & Wyss 1999
  • ?†Klohnia major Goin et all 2010
  • ?†Epiklohnia verticalis Goin et all 2010
  • ?†Praedens aberrans Goin et all 2010
• Family †Ferugliotheriidae Bonaparte 1986
  • †Ferugliotherium windhauseni Bonaparte 1986a [Vucetichia Bonaparte 1990; Vucetichia gracilis Bonaparte 1990]
  • †Trapalcotherium matuastensis Rougier et al. 2008
• Family †Sudamericidae Scillato-Yané & Pascual 1984 [Gondwanatheridae Bonaparte 1986]
  • †Greniodon sylvanicum Goin et al. 2012
  • †Vintana sertichi Krause et al. 2014
  • †Dakshina jederi Wilson, Das Sarama & Anantharaman 2007
  • †Gondwanatherium patagonicum Bonaparte 1986
  • †Sudamerica ameghinoi Scillato-Yané & Pascual 1984
  • †Lavanify miolaka Krause et al. 1997
  • †Bharattherium bonapartei Prasad et al. 2007
  • †Patagonia peregrina Pascual & Carlini 1987
  • †TNM 02067

外部聯繫

• Mesozoic Mammals - Gondwanatheria