División Paleontología Vertebrados, Museo de La Plata, La Plata, Buenos Aires, Argentina.
CONICET, Argentina.
J Anat. 2021 Aug;239(2):405-423. doi: 10.1111/joa.13430. Epub 2021 Mar 15.
Rodents are the most diverse order of extant mammals, and caviomorph rodents, or New World hystricognaths, have a remarkable morphological disparity and a long fossil record that begins in the Eocene. Chinchilloidea is a poorly understood clade within Caviomorpha, from an evolutionary and phylogenetic perspective. It includes the extant families Chinchillidae and Dinomyidae, the extinct Neoepiblemidae and Cephalomyidae, and several extinct chinchilloids without a clear phylogenetic position, like Eoincamys, Borikenomys, Chambiramys, Ucayalimys, Incamys, Saremmys, Garridomys and Scotamys. The family Chinchillidae includes the extant Chinchilla and Lagidium, grouped in Chinchillinae, and the only living Lagostominae, Lagostomus maximus. Among extinct chinchillids, Eoviscaccia (early Oligocene-early Miocene of Argentina, Bolivia and Chile), Prolagostomus (early-middle Miocene of Argentina, Bolivia and Chile) and Pliolagostomus (early-middle Miocene of Argentina) are the only genera originally described as members of the family. Based on the study of specimens with unworn or little-worn cheek teeth, belonging to extinct and extant taxa, we propose homologies of the cheek teeth structures and perform a combined molecular and morphological phylogenetic analysis including extinct and extant taxa of all families of Chinchilloidea and all genera of Chinchillidae. Our phylogenetic analysis recovered three major lineages in the evolutionary history of Chinchilloidea. The first major lineage is composed of the extant taxa Chinchilla, Lagidium and Lagostomus, and the extinct genera Eoviscaccia, Prolagostomus, Pliolagostomus, Garridomys, Incamys, Loncolicu and Saremmys. Cephalomyid (Banderomys, Cephalomys, Litodontomys, Soriamys) and neoepiblemid (Neoepiblema, Perimys, Phoberomys, Scotamys) genera are part of the second major lineage, while dinomyids such as Dinomys, Drytomomys, Scleromys, 'Scleromys' and Tetrastylus constitute the third major lineage within Chinchilloidea. The phylogenetic position of some taxa previously considered as incertae sedis chinchilloids or without a clear suprageneric group (i.e. Incamys, Saremmys, Garridomys and Loncolicu) show that they belong to pan-Chinchillidae and conform the stem Chinchillidae along with Eoviscaccia. The euhypsodont crown Chinchillidae includes the living subfamilies Chinchillinae and Lagostominae. Dinomyidae and Eoincamys pascuali are recovered as the sisters of a major clade composed by 'Cephalomyidae'+Neopiblemidae and pan-Chinchillidae, and Chambiramys sylvaticus occupies a basal position to the same clade. Four major radiation events are identified in the evolutionary history of Chinchilloidea. The analysis of new morphological characters linked with molecular evidence as well as the addition of taxa of uncertain or unstable phylogenetic position or not considered in previous studies allowed us resolve part of the relationships within Chinchilloidea, particularly that of Chinchillidae, supporting preceding morphological hypotheses.
啮齿动物是现存哺乳动物中最多样化的目，而新域豪猪类啮齿动物，或新世界豪猪类，具有显著的形态差异和始于始新世的长期化石记录。从进化和系统发育的角度来看，绒鼠形亚目是豪猪形亚目内一个了解甚少的分支。它包括现存的绒鼠科和豚鼠科，已灭绝的新兔形目和副鼠科，以及几个没有明确系统发育位置的已灭绝绒鼠类，如伊欧坎米斯、博里肯诺米斯、查姆比拉米斯、乌卡亚利米斯、伊诺卡米斯、萨雷米斯、加里多米斯和斯科塔米斯。绒鼠科包括现存的绒鼠和拉吉姆，它们被归为绒鼠亚科，以及唯一现存的拉格斯托米亚科，拉格斯托姆斯·马克西姆斯。在已灭绝的绒鼠中，伊沃斯卡夏（阿根廷、玻利维亚和智利的早始新世至早中新世）、普罗拉格斯托姆斯（阿根廷、玻利维亚和智利的中始新世至早中新世）和普利亚格斯托姆斯（阿根廷的中始新世至早中新世）是最初被描述为该科成员的唯一属。基于对属于已灭绝和现存分类群的未磨损或磨损很少的颊齿标本的研究，我们提出了颊齿结构的同源性，并对包括绒鼠形亚目所有科的已灭绝和现存分类群以及绒鼠科所有属的分子和形态系统发育分析进行了综合分析。我们的系统发育分析在绒鼠形亚目的进化历史中恢复了三个主要的进化枝。第一个主要的进化枝由现存的分类群绒鼠、拉吉姆和拉格斯托姆斯，以及已灭绝的属伊沃斯卡夏、普罗拉格斯托姆斯、普利亚格斯托姆斯、加里多米斯、伊诺卡米斯、隆科利库和萨雷米斯组成。副鼠科（班德拉鼠、副鼠、利顿托米斯、索里亚鼠）和新兔形目（新兔形目、佩里姆鼠、菲伯罗米斯、斯科塔米斯）属是第二个主要进化枝的一部分，而豚鼠科如豚鼠、干燥豚鼠、斯克里莫鼠、“斯克里莫鼠”和四足鼠则构成了绒鼠形亚目内的第三个主要进化枝。以前被认为是不确定地位的绒鼠类或没有明确的上科群的一些分类群（即伊诺卡米斯、萨雷米斯、加里多米斯和隆科利库）的系统发育位置表明，它们属于泛绒鼠科，并与伊沃斯卡夏一起构成绒鼠科的基部。真齿冠绒鼠科包括现存的绒鼠亚科和拉格斯托米亚科。豚鼠科和伊欧坎米斯·帕斯库利被认为是由“副鼠科+新兔形目”和泛绒鼠科组成的主要进化枝的姐妹群，而查姆比拉米斯·西尔瓦提库斯则占据了同一进化枝的基部位置。在绒鼠形亚目的进化历史中，有四个主要的辐射事件。对与分子证据相关的新形态特征的分析，以及对不确定或不稳定系统发育位置的分类群或以前研究中未考虑的分类群的添加，使我们能够解决绒鼠形亚目内部的部分关系，特别是绒鼠科的关系，支持了以前的形态假说。
