A morphological revision of Keraterpeton, the earliest horned nectridean from the Pennsylvanian of England and Ireland

ABSTRACTThe aquatic diplocaulid nectridean Keraterpeton galvani is the commonest taxon represented in the Jarrow Coal assemblage from Kilkenny, Ireland. The Jarrow locality has yielded the earliest known Carboniferous coal-swamp fauna in the fossil record and is, therefore, of importance in understanding the history and diversity of the diplocaulid clade. The morphology of Keraterpeton is described in detail with emphasis on newly observed anatomical features. A reconstruction of the palate includes the presence of interpterygoid vacuities and new morphological details of the pterygoid, parasphenoid and basicranial region. The hyoid apparatus comprising an ossified basibranchial element has not been reported previously in nectrideans. The structure of the scapulocoracoid and primitive nature of the humerus is described and the presence of a five-digit manus confirmed. Previously unrecognised accessory dermal ossifications are present in the pectoral girdle. Keraterpeton longtoni from the Bolsovian in Staffordshire, England, is also described and newly figured. The primitive condition in diplocaulids is defined on the basis of the earliest occurrence at Jarrow and discussed in relation to functional morphology and mode of life. The evolution of the diplocaulid clade is assessed in relation to the revised diagnoses that define the primitive condition in Keraterpeton.

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First Carboniferous thylacocephalan from Europe and its significance for the understanding of functional morphology of Concavicarididae Schram, 2014

Crustaceana ◽

10.1163/15685403-00003771 ◽

2018 ◽

Vol 91 (3) ◽

pp. 265-285 ◽

Cited By ~ 2

Author(s):

Štěpán Rak ◽

Krzysztof Broda ◽

Tomáš Kumpan

Keyword(s):

New Species ◽

Functional Morphology ◽

Fossil Record ◽

Free Swimming ◽

Lower Carboniferous ◽

Form And Function ◽

Mode Of Life ◽

Moravian Karst ◽

And Function ◽

Evolutionary Aspects

Thylacocephala Pinna, Arduini, Pesarini & Teruzzi 1982 are among the most enigmatic arthropods. Their fossil record is very patchy both geographically and stratigraphically. In this paper we describe the first thylacocephalan known from the Carboniferous (Mississippian) of Europe, Concavicaris viktoryni sp. nov. Until now Carboniferous representatives of Thylacocephala were know exclusively from the U.S.A. We discuss the stratigraphic and geological context of occurrence of this new species as well as form and function of the unique carapace micro- and macro-ornamentation. A shape and assumed function of the characteristic lirae on the C. viktoryni sp. nov. carapace present an important supporting argument for the supposed free-swimming or pelagic mode of life in thylacocephalans. Palaeobiogeographical and evolutionary aspects of surprisingly rich but local occurrence of thylacocephalans in the Lower Carboniferous of the Moravian karst are discussed. Possible sympatric evolution from its predecessor Concavicaris incola is also pointed out.

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Functional Morphology of Wings from the Standpoint of Adaptation for Flight in Chiroptera : II. Growth and Changes in Mode of Life during the Young Period in Rhinolophus cornutus cornutus

Journal of the Faculty of Agriculture, Kyushu University ◽

10.5109/23690 ◽

1979 ◽

Vol 23 (3/4) ◽

pp. 185-198

Author(s):

Keiichi Yokoyama ◽

Teruaki Uchida

Keyword(s):

Functional Morphology ◽

Mode Of Life

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The ecology of invasion: acquisition and loss of the siphonal canal in gastropods

Paleobiology ◽

10.1666/06061.1 ◽

2007 ◽

Vol 33 (3) ◽

pp. 469-493 ◽

Cited By ~ 9

Author(s):

Geerat J. Vermeij

Keyword(s):

Functional Data ◽

Fossil Record ◽

Energy Savings ◽

Comparative Approach ◽

Marine Gastropods ◽

Front End ◽

Middle Paleozoic ◽

Mode Of Life ◽

Determinate Growth ◽

Slow Moving

AbstractMost evolutionary innovations—power-enhancing phenotypes previously absent in a lineage—have arisen multiple times within major clades. This repetition permits a comparative approach to ask how, where, when, in which clades, and under which circumstances adaptive innovations are acquired and secondarily lost. I use new and literature-based data on the phylogeny, functional morphology, and fossil record of gastropods to explore the acquisition and loss of the siphonal canal and its variations in gastropods. The siphonal indentation, canal, notch, or tube at the front end of the shell is associated in living gastropods with organs that detect chemical signals directionally and at a distance in an anteriorly restricted inhalant stream of water.Conservative estimates indicate that the siphonate condition arose 23 times and was secondarily lost 17 times. Four siphonate clades have undergone prodigious diversification. All siphonate gastropods have a shell whose axis of coiling lies at a low angle above the plane of the aperture (retroaxial condition). In early gastropods, the siphonal canal was short and more or less confined to the apertural plane. Later (mainly Cretaceous and Cenozoic) variations include a dorsally deflected canal, a long canal, and a closed canal. The closed siphonal canal, in which the edges join to form a tube, arose 15 times, all in the adult stages of caenogastropods with determinate growth.Gastropods in which the siphonate condition arose were mobile, bottom-dwelling, microphagous animals. Active predaceous habits became associated with the siphonate condition in the Mesozoic and Cenozoic Purpurinidae-Latrogastropoda clade. Loss of the siphonate condition is associated with nonmarine habits, miniaturization, and especially with a sedentary or slow-moving mode of life.The siphonate condition arose seven times each during the early to middle Paleozoic, the late Paleozoic, and the early to middle Mesozoic, and only once each during the Late Cretaceous and Cenozoic. Well-adapted incumbents prevented most post-Jurassic clades from evolving a siphonal indentation and its associated organs. Dorsally deflected, long, and closed canals are known only from Cretaceous and Cenozoic marine gastropods, and represent improvements in sensation and passive armor.In a discussion of contrasting ecologies of clades that gained and lost the siphonate condition, I argue that macroevolutionary trends in the comings and goings of innovations and clades must incorporate ecological and functional data. Acquisitions of energy-intensive, complex innovations that yield greater power have a greater effect on ecosystems, communities, and their resident clades than do reversals, which generally reflect energy savings.

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A new Late Cretaceous iguanomorph from North America and the origin of New World Pleurodonta (Squamata, Iguania)

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.1902 ◽

2017 ◽

Vol 284 (1847) ◽

pp. 20161902 ◽

Cited By ~ 7

Author(s):

David G. DeMar ◽

Jack L. Conrad ◽

Jason J. Head ◽

David J. Varricchio ◽

Gregory P. Wilson

Keyword(s):

North America ◽

Late Cretaceous ◽

Fossil Record ◽

New World ◽

Cladistic Analysis ◽

Arid Environment ◽

New Taxon ◽

Low Latitude ◽

Anatomical Features ◽

Parietal Foramen

Iguanomorpha (stem + crown Iguania) is a diverse squamate clade with members that predominate many modern American lizard ecosystems. However, the temporal and palaeobiogeographic origins of its constituent crown clades (e.g. Pleurodonta (basilisks, iguanas, and their relatives)) are poorly constrained, mainly due to a meagre Mesozoic-age fossil record. Here, we report on two nearly complete skeletons from the Late Cretaceous (Campanian) of North America that represent a new and relatively large-bodied and possibly herbivorous iguanomorph that inhabited a semi-arid environment. The new taxon exhibits a mosaic of anatomical features traditionally used in diagnosing Iguania and non-iguanian squamates (i.e. Scleroglossa; e.g. parietal foramen at the frontoparietal suture, astragalocalcaneal notch in the tibia, respectively). Our cladistic analysis of Squamata revealed a phylogenetic link between Campanian-age North American and East Asian stem iguanomorphs (i.e. the new taxon + Temujiniidae). These results and our evaluation of the squamate fossil record suggest that crown pleurodontans were restricted to the low-latitude Neotropics prior to their early Palaeogene first appearances in the mid-latitudes of North America.

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The Mode of Life in the Genus Pholadomya as Inferred from the Fossil Record

Geosciences ◽

10.3390/geosciences10100397 ◽

2020 ◽

Vol 10 (10) ◽

pp. 397

Author(s):

Przemysław Sztajner

Keyword(s):

Fossil Record ◽

Mode Of Life ◽

Morphological Differences

The paper is an attempt to reconstruct the mode of life of Pholadomya bivalves, very common in the fossil record, particularly that of the Jurassic. The only extant representative of the genus is extremely rare and very poorly known. Materials from the Polish Jurassic deposits (Bajocian–Kimmeridgian; Western Pomerania and Polish Jura) and literature data were used for the reconstruction. Specifically, observations on the anatomy, taphonomy, and diagenesis of the specimens examined as well as lithology of the deposits housing the specimens were used. Shell anatomy characteristics are known for their particular utility in mode of life reconstructions, although the extremely thin-shelled and coarsely sculpted bivalves, such as the Pholadomya examined, have not been studied so far. The reconstruction suggest a diversity of the mode of life, coincident with the morphological differences between the Pholadomya species. At least the adults of anteriorly flattened species are inferred to have lived extremely deeply buried in the sediment, and were hardly mobile. The smaller, more oval in shape, species were more mobile, and some of them are thought to have preferred life in shelters, should those be available. In addition, the function of the cruciform muscle, other than that considered so far, is suggested.

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Evolution and adaptive radiation in the chydoridae (crustacea: cladocera): a study in comparative functional morphology and ecology

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1968.0017 ◽

1968 ◽

Vol 254 (795) ◽

pp. 221-384 ◽

Cited By ~ 182

Keyword(s):

Functional Morphology ◽

Adaptive Radiation ◽

Basic Mechanism ◽

Ecological Niches ◽

Anatomical Features ◽

Progressive Development ◽

The Family ◽

Ways Of Life ◽

Great Complexity ◽

Original Type

(Numbers given in the summary refer to certain key figures in the text which facilitate understanding.) An account is given of the functional morphology, ecology, habits and feeding mechanisms, of a representative series of anomopod cladocerans of the family Chydoridae, embracing some 22 species belonging to 15 genera. Of these genera two are defined as new on the basis of this investigation. Habits, which often depend on anatomical specializations of great complexity, are more diverse than has been supposed, and permit the exploitation of a diversity of ecological niches. The functional significance of many anatomical features is described. Carapace specializations, previously almost unstudied, are extremely important. Fundamental homologies not only within the Chydoridae but within the Anomopoda as a whole, can now be recognized and the feeding mechanism of all species can be related to one original type. By subtle modification of its various components, however, this basic mechanism has been adapted to very different ways of life and to different functions. The various species are described in a sequence which in part illustrates the progressive development of specialized ways of life rather than phylogeny, but light has been thrown on affinities, or lack of affinity, between certain species.

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Geological and palaeontological information and phylogenetic hypotheses

Geological Magazine ◽

10.1017/s0016756800010165 ◽

1988 ◽

Vol 125 (3) ◽

pp. 207-227 ◽

Cited By ~ 30

Author(s):

K. S. W. Campbell ◽

R. E. Barwick

Keyword(s):

Functional Morphology ◽

Fossil Record ◽

Early Permian ◽

Phylogenetic Hypothesis ◽

Geological Data ◽

Early Devonian ◽

Aerial Respiration ◽

Phylogenetic Relations ◽

Phylogenetic Hypotheses ◽

Physiological Characters

AbstractA number of workers have accepted the proposition that phylogenetic relations between extant organisms can be determined only by reference to the characters of those organisms. Palaeontological data, it is said, have not been useful for developing or refuting such hypotheses. This view may be tested by reference to the respiratory mechanisms of dipnoans (lungfishes) and amphibians. The structure of the heart, lungs, and circulatory systems has been used by various authors to support the view that these are sister groups. Geological data derived from stratigraphy, palaeoecology, taphonomy, geochemistry and functional morphology of primitive dipnoans is used herein to show that these organisms did not engage in aerial respiration. The first unequivocal evidence that dipnoans had become air breathers is from aestivation burrows in Early Permian rocks of the U.S.A. The Dipnoi must have evolved this capacity at some time between the Early Devonian, when the group became well established, and the Early Permian. Similarities between the respiratory systems of extant dipnoans and amphibians must be the result of convergence, or of the derivation of the Amphibia directly from the Dipnoi. The latter view is not currently accepted by any workers in the field. Thus data from the fossil record are used to demonstrate the invalid use of some neontological data for the development of a phylogenetic hypothesis. Classifications of extant organisms depending on putative shared–derived morphological or physiological characters that cannot be adequately tested for convergence by reference to fossils, must be regarded with due caution.

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On certain Semi-carnivorous Anthomyid Larvae

Parasitology ◽

10.1017/s0031182000011045 ◽

1930 ◽

Vol 22 (2) ◽

pp. 168-181 ◽

Cited By ~ 17

Author(s):

D. Keilin ◽

P. Tate

Keyword(s):

Alimentary Canal ◽

Body Wall ◽

Anatomical Structure ◽

The Body ◽

Sensory Organs ◽

Ventral Region ◽

Anatomical Features ◽

Mode Of Life ◽

Ventral Wall

In previous papers one of us (Keilin, 1915, 1917) has shown that among cyclorrhaphous dipterous larvae there is a remarkable correlation between the anatomical structure of the larvae and their mode of life. Although the mode of life of the larvae is in correlation with such anatomical features as thickness and hardness of the body-wall, the development of sensory organs on the head, and the structure of the alimentary canal, it is in the bucco-pharyngeal armature that the most obvious and important adaptations are to be found. The most important of these adaptations may be mentioned briefly. In certain cyclorrhaphous dipterous larvae the ventral wall of the basal sclerite of the bucco-pharyngeal armature has a number of longitudinal ridges projecting into the lumen of the pharynx. These ridges are usually Y-shaped at their free borders, and form a series of longitudinal channels in the ventral region of the pharynx. In other cyclorrhaphous dipterous larvae such ridges are absent and the ventral wall of the pharynx is smooth. This character allows the larvae to be divided into two groups—“all cyclorrhaphous dipterous larvae parasitic on the most diverse animals or on plants, as well as carnivorous larvae, and larvae which suck the blood of mammals, never have ridges in their pharynx; on the contrary, ridges are always present in saprophagous larvae” (Keilin, 1915). All the larvae which are devoid of ridges and are either parasitic, carnivorous, pass their whole life in the uterus of the female, or are phytophagous, may be united into the group of biontophagous; all larvae which have ridges are saprophagous.

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