冈瓦那兽目

冈瓦那兽目 化石時期： 坎帕阶-中新世, （可能在侏罗纪出现）
科學分類
界： 动物界 Animalia 門： 脊索动物门 Chordata 亞門： 脊椎动物亚门 Vertebrata 綱： 哺乳纲 Mammalia 目： 冈瓦那兽目 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

冈瓦那兽目（学名：Gondwanatheria，亦可称为冈瓦纳兽目）是哺乳动物中一个已经灭绝的目，生活在上白垩世至中新世（且可能更早，如果将Allostaffia划为该目的成员）的南半球，包括南极洲。该类群为人所知的仅有数颗分离的牙齿，几片下颌骨，两块不完整的头骨和一个完整的头盖骨 。正是因为这种零碎的知识，其分类地位不甚清晰。

分类

Vintana sertichi的重建图。除头部外的身体部分为想象图。

该类群分类关系的不明确持续了几十年，其最开始被认为是早期的异关节总目动物，一种“无齿”的哺乳动物，接近现代的食蚁兽。随后的多个不同研究认为它们属于异兽亚纲，接近多瘤齿兽目，甚至可能真正属于多瘤齿兽目，比Cimolodonta亚目更接近于Plagiaulacida亚目。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.

生物学

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.

分类

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

外部联系

• Mesozoic Mammals - Gondwanatheria