author={Tiiu M{\"a}rss and Pierre-Yves Gagnier},
Abstract Kannathalepis milleri, gen. et sp. nov. is described from the Upper Sheinwoodian to Lower Homerian interval (Wenlock) of the Baillie-Hamilton Island section, Canadian Arctic. Based on several distinct features, such as the occurrence of several canals in the neck region, much smaller length of the wide and short base compared to the crown, presence of compound scales, character of dentine canals and tubules, and specific ultrasculpture of the crown, the new taxon Kannathalepis milleri… 

Upper Ordovician chondrichthyan‐like scales from North America

This study contributes to a growing body of evidence that reveals the presence of diverse tissue types (bone, tubular and atubular dentine) and morphogenetic patterns in the dermal skeleton of putative Ordovician chondrichthyans.

Palaeocope ostracods from the Silurian Wenlock Series of Arctic Canada

Silurian Wenlock Series deposits of the Cape Phillips Formation on Baillie-Hamilton Island and Cornwallis Island, Arctic Canada, have yielded a silicified ostracod assemblage that spans the late

The braincase of the chondrichthyan Doliodus from the Lower Devonian Campbellton Formation of New Brunswick, Canada

Doliodus has curious bar-like, paired subcranial ridges ending posteriorly at the hyomandibular articulation, adding circumstantial palaeontological support to the old proposal that parts of visceral arches may be incorporated into the gnathostome braincase, although it seems more plausible that they formed in the lateral margins of the embryonic parachordal or hypotic lamina.

The systematics of the Mongolepidida (Chondrichthyes) and the Ordovician origins of the clade

The present study reassesses mongolepid systematics through the examination of the developmental, histological and morphological characteristics of scale-based specimens from the Upper Ordovician Harding Sandstone and the Upper Llandovery–Lower Wenlock Yimugantawu (Tarim Basin, China), Xiushan (Guizhou Province, China) and Chargat (north-western Mongolia) Formations.

The morphology and sculpture of ossicles in the Cottidae (Teleostei) of the Baltic Sea

Small to very small ossified structures (ossicles) such as cephalic horns, dermal tubercles, fin-ray rods, lateral-line canal segments, branchial tooth plates and gill-raker tubercles of three

The early evolutionary history of sharks and shark-like fishes

It is proposed that chondrichthyan dermoskeletal characters carry a phylogenetic signal, allowing to interpret the documented diverse types of scale morphogenesis as evidence for a major radiation of chondRichthyan lineages in the Lower Palaeozoic.

Modeling Scale Morphogenesis in a Devonian Chondrichthyan and Scale Growth Patterns in Crown Gnathostomes

This study provides the first 3D virtual growth model of stem chondrichthyan scales with a Seretolepis-type morphogenesis, offering new insights into the early evolution of chondRichthyan dermal skeletons.

Chapter 28 Palaeobiogeography of Early Palaeozoic vertebrates

Abstract The oldest known Palaeozoic vertebrate record currently is Early Cambrian in age. The first taxa with mineralized exoskeletons are at least Ordovician in age, followed by a sporadic fossil

Enameloid microstructure in the oldest known chondrichthyan teeth

Results show that a superficial cap of SCE is present in the oldest shark teeth known, which suggest its presence in the most basal chondrichthyans.


Systematic treatment of the ultrasculpture on the exoskeleton of Palaeozoic Agnatha is given, supplemented with a discussion of the main published sources on Gnathostomata, to show relationships between thelodonts and chondrichthyans based on ultrasculPTure characteristics are much more complicated than previously discussed.



A microvertebrate fauna from the Llandovery of South China

Abstract The late Llandovery (early Silurian) of South China has yielded a locally abundant and diverse microvertebrate fauna. This includes scales of the little-known mongolepids, sinacanthid spines

Agnathan vertebrates in the Lower Silurian of Gotland, Sweden

Abstract The vertebrate scale collections from the Telychian? (upper Llandovery) Lower Visby Beds to the Gorstian? (lower Ludlow) upper Klinteberg Beds mostly represent low diversity thelodont

The microstructure of the dentition and dermal ornament of three dipnoans from the devonian of Western Australia: a contribution towards dipnoan interrelations, and morphogenesis, growth and adaptation of the skeletal tissues.

  • M. M. Smith
  • Biology
    Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 1977
The phyletic trend towards macromerism, as shown in chondricthyans and primitive teleostomes, is illustrated in the three species of dipnoan, and the loss of cosmine and replacement by tubercles in Griphognathus whitei and Holodipterus gogoensis is explained as retention of an ontogenetic potential which is comparable with Orvig's theory ofcosmine regression in the porolepids.

Ausgangsform und Entwicklung der rhombischen Schuppen der Osteichthyes (Pisces)

Ganoid and cosmoid scales, the two types of rhombic scales within the osteichthyans, can be traced back to a primitive scale similar to the scales ofLophosteus. The primitive rhombic scale did not

Determination Methods for the Exoskeletal Remains of Early Vertebrates

For determination of discrete exoskeletal elements, their morphology, internal structure, defined tissue types of crown and basal plate, types of their growth, system of vascular canals should be studied in addition changes occuring during ontogenetic development of both the dermal skeletal elements and the squamation should be taken in consideration.

Types of morphogenesis of the dermal skeleton in fossil sharks

The adaptive significance, both of different type of morphogenesis of the dermal skeleton as well as different types of scale shapes, is discussed.

Evolution of Dermal Skeleton and Dentition in Vertebrates

The starting point of comparative evolutionary studies of the dermal skeleton of vertebrates is Hertwig’s series of papers (1874, 1876/1879/1882), which directly stimulated many dozens of papers,

The fossil record 2

This chapter discusses the main groups of the phylum Protozoa, which consists of Invertebrates, Amphibian-grade Tetrapoda, and Plants, and their relationships to each other.