相关论文

论文信息：（一）

【论文题目】An ExceptionallyPreserved Three-Dimensional Armored Dinosaur Reveals Insights into Colorationand Cretaceous Predator-Prey Dynamics

【论文作者】Caleb M.Brown,Donald M. Henderson, et al.

【发表日期】2017年8月3日

【发表期刊】CurrentBiology

【论文链接】http://www.cell.com/current-biology/fulltext/S0960-9822(17)30808-4

【论文编号】DOI: http://dx.doi.org/10.1016/j.cub.2017.06.071

【论文摘要】Predator-preydynamics are an important evolutionary driver of escalating predation mode andefficiency, and commensurate responses of prey. Among these strategies, camouflage is important forvisual concealment, with countershading the most universally observed. Extantterrestrial herbivores free of significant predation pressure, due to largesize or isolation, do not exhibit countershading. Modern predator-prey dynamicsmay not be directly applicable to those of the Mesozoic due to the dominance ofvery large, visually oriented theropod dinosaurs. Despite thyreophorandinosaurs’ possessingextensive dermal armor, some of the most extreme examples of anti-predatorstructures, little direct evidence of predation on these and other dinosaurmegaherbivores has been documented. Here we describe a new, exquisitelythree-dimensionally preserved nodosaurid ankylosaur, Borealopelta markmitchelligen. et sp. nov., from the Early Cretaceous of Alberta, which preservesintegumentary structures as organic layers, including continuous fields ofepidermal scales and intact horn sheaths capping the body armor. We identifymelanin in the organic residues through mass spectroscopic analyses and observelighter pigmentation of the large parascapular spines, consistent with display,and a pattern of countershading across the body. With an estimated body massexceeding 1,300 kg, B. markmitchelli was much larger than modern terrestrialmammals that either are countershaded or experience significant predationpressure as adults. Presence of countershading suggests predation pressurestrong enough to select for concealment in this megaherbivore despitepossession of massive dorsal and lateral armor, illustrating a significantdichotomy between Mesozoic predator-prey dynamics and those of modernterrestrial systems.

论文信息：（二）

【论文题目】Synchrotronscanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs

【论文作者】Andrea Cau,Vincent Beyrand,et al.

【发表日期】2017年12月21日

【发表期刊】Nature

【论文链接】https://www.nature.com/articles/nature24679

【论文编号】doi:10.1038/nature24679

【论文摘要】Maniraptoraincludes birds and their closest relatives among theropod dinosaurs. During theCretaceous period, several maniraptoran lineages diverged from the ancestralcoelurosaurian bauplan and evolved novel ecomorphologies, including activeflight, gigantism, cursoriality and herbivory. Propagation X-ray phase-contrastsynchrotron microtomography of a well-preserved maniraptoran from Mongolia,still partially embedded in the rock matrix, revealed a mosaic of features,most of them absent among non-avian maniraptorans but shared by reptilian andavian groups with aquatic or semiaquatic ecologies. This new theropod, Halszkaraptor escuilliei gen. et sp.nov., is related to other enigmatic Late Cretaceous maniraptorans from Mongoliain a novel clade at the root of Dromaeosauridae. This lineage adds anamphibious ecomorphology to those evolved by maniraptorans: it acquired apredatory mode that relied mainly on neck hyperelongation for food procurement,it coupled the obligatory bipedalism of theropods with forelimb proportionsthat may support a swimming function, and it developed postural adaptationsconvergent with short-tailed birds.

原文链接：https://www.theguardian.com/science/2017/dec/28/top-fossil-discoveries-of-2017

论文信息：（三）

【论文题目】An Eoceneorthocone from Antarctica shows convergent evolution of internally shelledcephalopods

【论文作者】Larisa A.Doguzhaeva,Stefan Bengtson,et al.

【发表日期】2017年3月1日

【发表期刊】PLOS One

【论文链接】http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172169

【论文编号】https://doi.org/10.1371/journal.pone.0172169

【论文摘要】The SubclassColeoidea (Class Cephalopoda) accommodates the diverse present-day internallyshelled cephalopod mollusks (Spirula, Sepia and octopuses, squids,Vampyroteuthis) and also extinct internally shelled cephalopods. Recent Spirula represents a uniquecoleoid retaining shell structures, a narrow marginal siphuncle and globularprotoconch that signify the ancestry of the subclass Coleoidea from thePaleozoic subclass Bactritoidea. This hypothesis has been recently supported bynewly recorded diverse bactritoid-like coleoids from the Carboniferous of theUSA, but prior to this study no fossil cephalopod indicative of anendochochleate branch with an origin independent from subclass Bactritoidea hasbeen reported. Two orthoconic conchs were recovered from the Early Eocene ofSeymour Island at the tip of the Antarctic Peninsula, Antarctica. They haveloosely mineralized organic-rich chitin-compatible microlaminated shell wallsand broadly expanded central siphuncles. The morphological, ultrustructural andchemical data were determined and characterized through comparisons with extantand extinct taxa using Scanning Electron Microscopy/Energy DispersiveSpectrometry (SEM/EDS). Our study presents the first evidence for anevolutionary lineage of internally shelled cephalopods with independent originfrom Bactritoidea/Coleoidea, indicating convergent evolution with the subclassColeoidea. A new subclass Paracoleoidea Doguzhaeva n. subcl. is established foraccommodation of orthoconic cephalopods with the internal shell associated witha broadly expanded central siphuncle. Antarcticerida Doguzhaeva n. ord.,Antarcticeratidae Doguzhaeva n. fam., Antarcticeras nordenskjoeldi Doguzhaevan. gen., n. sp. are described within the subclass Paracoleoidea. The analysisof organic-rich shell preservation of A. nordenskjoeldi by use of SEM/EDStechniques revealed fossilization of hyposeptal cameral soft tissues. Thissuggests that a depositional environment favoring soft-tissue preservation wasthe factor enabling conservation of the weakly mineralized shell of A.nordenskjoeldi.

论文信息：（四）

【论文题目】Earth’s oldest ‘Bobbit worm’– gigantismin a Devonian eunicidan polychaete

【论文作者】Mats E.Eriksson, Luke A. Parry & David M. Rudkin

【发表日期】2017年1月17日

【发表期刊】Nature-ScientificReports

【论文链接】https://www.nature.com/articles/srep43061

【论文编号】doi:10.1038/srep43061

【论文摘要】Whilst thefossil record of polychaete worms extends to the early Cambrian, much data onthis group derive from microfossils known as scolecodonts. These are sclerotized jaw elements,which generally range from 0.1–2mm in size, and which, in contrast to the soft-bodyanatomy, have good preservation potential and a continuous fossil record. Herewe describe a new eunicidan polychaete, Websteroprion armstrongi gen. et sp.nov., based primarily on monospecific bedding plane assemblages from theLower-Middle Devonian Kwataboahegan Formation of Ontario, Canada. The specimensare preserved mainly as three-dimensional moulds in the calcareous host rock,with only parts of the original sclerotized jaw walls occasionally present.This new taxon has a unique morphology and is characterized by an unexpectedcombination of features seen in several different Palaeozoic polychaetefamilies. Websteroprion armstrongi was a raptorial feeder and possessed thelargest jaws recorded in polychaetes from the fossil record, with maxillaereaching over one centimetre in length. Total body length of the species isestimated to have reached over one metre, which is comparable to that of extant‘gianteunicid’ speciescolloquially referred to as ‘Bobbit worms’. This demonstrates that polychaete gigantism wasalready a phenomenon in the Palaeozoic, some 400 million years ago.

论文信息：（五）

【论文题目】A new hornedand long-necked herbivorous stem-archosaur from the Middle Triassic of India

【论文作者】SaradeeSengupta,Martín D. Ezcurra & Saswati Bandyopadhyay

【发表日期】2017年7月21日

【发表期刊】Nature-ScientificReports

【论文链接】https://www.nature.com/articles/s41598-017-08658-8

【论文编号】doi:10.1038/s41598-017-08658-8

【论文摘要】The earlyevolution of archosauromorphs (bird- and crocodile-line archosaurs andstem-archosaurs) represents an important case of adaptive radiation thatoccurred in the aftermath of the Permo-Triassic mass extinction. Here we enrichthe early archosauromorph record with the description of a moderately large (3–4m in totallength), herbivorous new allokotosaurian, Shringasaurus indicus, from the earlyMiddle Triassic of India. The most striking feature of Shringasaurus indicus isthe presence of a pair of large supraorbital horns that resemble those of someceratopsid dinosaurs. The presence of horns in the new species is dimorphicand, as occurs in horned extant bovid mammals, these structures were probablysexually selected and used as weapons in intraspecific combats. The relativelylarge size and unusual anatomy of Shringasaurus indicus broadens themorphological diversity of Early–Middle Triassic tetrapods and complements theunderstanding of the evolutionary mechanisms involved in the earlyarchosauromorph diversification.

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