[PaleoIchthyology • 2006] อีสานอิกธิส พาลัสทริส | Isanichthys palustris • A new Semionotiform (Actinopterygii, Neopterygii) from Upper Jurassic - Lower Cretaceous Deposits of northeastern Thailand, with Comments on the Relationships of Semionotiforms

อีสานอิกธิส พาลัสทริส 

Isanichthys palustris Cavin & Suteethorn 2006

Abstract

  A new semionotiform fish, Isanichthys palustris gen. et sp. nov., is described from the Late Jurassic – Early Cretaceous Phu Kradung Formation, north-east Thailand. I. palustris is known from a single, nearly complete specimen found alongside abundant Lepidotes specimens at the Phu Nam Jun locality. I. palustris shows a mixture of semionotid-like characters, such as the pattern of cheek ossifications, and lepisosteid-like characters, such as the body shape and a dorsal fin opposed by an anal fin. I. palustris possesses only some of the characters currently used to define the Semionotidae. Cladistic analyses including various semionotid and gar taxa, together with Amia calva and Leptolepis coryphaenoides, suggest that the Semionotiformes (Lepisosteidae and ‘Semionotidae’) form a monophyletic clade, but the ‘Semionotidae’ taxa form an unresolved polytomy. The relationships between Semionotiformes, Halecomorphi and Teleostei are unresolved. When restricted to the best-known taxa, however, the analysis shows the monophyly of the Semionotidae sensu stricto (Semionotus + Lepidotes) and a sister-group relationship between halecomorphs and teleosts. These last two results are regarded as the preferred hypothesis for further studies. I. palustris is the only known example of a predaceous, probably piscivorous, ‘semionotid’. It illustrates the great diversity and ecological adaptation of the semionotiforms during the Late Jurassic – Early Cretaceous. We question the phylogenetic relationships of ‘ancient fishes’ founded on molecular-based trees because we suspect that the use of very few Recent taxa as representatives of previously diverse lineages is an inevitable, but important, bias in the construction of such trees.

Keywords: Actinopterygii; Semionotiformes; Lepisosteidae; new taxon; Thailand; Mesozoic; phylogeny

Cavin, L. & Suteethorn, V. 2006. A new Semionotiform (Actinopterygii, Neopterygii) from Upper Jurassic - Lower Cretaceous Deposits of North-East Thailand, with Comments on the Relationships of Semionotiforms. Palaeontology. 49, 339–353 : http://dx.doi.org/10.1111/j.1475-4983.2006.00539.x

[PaleoIchthyology • 2007] สยามเอเมีย นาคา | Siamamia naga • The first sinamiid fish (Holostei, Halecomorpha) from Southeast Asia (Early Cretaceous of Thailand)

 

สยามเอเมีย นาคา | Siamamia naga 

Cavin, Suteethorn, Buffetaut, Claude, Cuny, Le Loeuff & Tong 2007

 Siamamia naga, gen. et sp. nov, is described on the basis of three partly articulated skulls and a collection of isolated ossifications from a continental Early Cretaceous Formation of northeastern Thailand. The new taxon is a sinamiid halecomorph as demonstrated by the median parietal and other cranial characters. Sinamiidae is hitherto known by two genera occurring in Early Cretaceous freshwater deposits in China. Although a complete revision of all species within the family is necessary, the Thai material shows characters justifying a new genus. It is the first sinamiid found outside eastern Asia (South and North Chinese blocks, plus small Central Asian terranes), thus validating the close paleogeographical affinities between mainland Asia and SE Asia in the Early Cretaceous. A preliminary phylogenetic assessment of the new taxon with the data matrix of Grande and Bemis (1998) with the addition of data for Siamamia and Tomognathus provides a strict consensus tree similar to the phylogenetic hypothesis of Halecomorphi proposed by these authors, except the basal-most amiids which show a lower resolution in our hypothesis. The Sinamiidae appear as a monophyletic clade, but the four taxa included in the analysis form a polytomy

Etymology — Siam, geographic (former name of Thailand), referring to locality, + Amia (Greek); Naga, mythological creature living in the Kong River (Maekong).

Lionel Cavin, Varavudh Suteethorn, Eric Buffetaut, Julien Claude, Gilles Cuny, Jean Le Loeuff & Haiyan Tong. 2007. The first sinamiid fish (Holostei, Halecomorpha) from Southeast Asia (Early Cretaceous of Thailand). Journal of Vertebrate Paleontology. 27(4) 

 http://dx.doi.org/10.1671/0272-4634(2007)27[827:TFSFHH]2.0.CO;2

[PaleoIchthyology • 2007] เฟอร์กาโนเซอราโตดัส มาร์ตินี | Ferganoceratodus martini • A new Thai Mesozoic lungfish (Sarcopterygii, Dipnoi) with an insight into post-Palaeozoic dipnoan evolution

We describe a new species of lungfish, Ferganoceratodus martini sp. nov., based on a single specimen discovered in the Late Jurassic – Early Cretaceous of the Phu Nam Jun locality, north-eastern Thailand. The material comprises an almost complete skull roof with associated upper and lower jaws, as well as some postcranial remains. F. martini shows characters unexpected and/or unknown in other Mesozoic lungfishes, such as pieces of a ‘hard snout’. The microstructure of the ‘hard snout’ provides support to the Bemis and Northcutt interpretation of the cosmine tissue of Palaeozoic lungfishes as homologous to the complex cutaneous vasculature of the living Neoceratodus. Because the homologies of the ossifications of the skull roof among lungfishes and among piscian sarcopterygians are unsatisfactorily understood, we use a topological nomenclature in the description of the specimen and in the discussion of post-Devonian dipnoan skull roof characters. We define a few characters for the cladistic analysis only, but these are regarded as less theory-laden. We propose a hypothesis of phylogenetic relationships for most of the post-Devonian forms known by skull remains. The main feature is the ancient dichotomy between the Neoceratodus lineage and most of the other Mesozoic forms, including the Lepidosirenids. The palaeobiogeographical pattern shows a series of vicariant events between Laurasia and Gondwana in the Late Triassic – Early Jurassic, followed by a vicariant event between Africa and South America.  

 Keywords: histology – new taxon – palaeoecology – palaeogeography – phylogeny – tooth plate.

Reconstitution of fossil lungfish Ferganoceratodus martini discovered in the Early Cretaceous (140 million years) in Thailand. © Lionel Cavin MHN / MHS

A, B: fossil lungfish Ferganoceratodus martini discovered in the Early Cretaceous (140 million years) in Thailand. C, D: Position of fossil inside the head of the animal. This fish has large enameled plates instead of teeth (visible between the eyes) he used to grind their food. E: reconstitution of lungfish. © Lionel Cavin MHN / MHS

Lionel Cavin, a paleontologist at the Natural History Museum of the City of Geneva (Switzerland) and Anne Kemp, a biologist at the Australian Rivers Institute, Brisbane (Australia), have recently shown that the lungfish, these curious primitive fish that have the both lungs and gills are much older and valuable than was previously thought.

Thailand discovering a fossil from the Lower Cretaceous (140 million years) belonging to this lineage of fish fossils and reviewing the Triassic (250 million years) from museum collections, the two researchers have shown that some lungfish belong to a branch very old, very special and long tree of evolution, as well as the famous coelacanth fish considered true living fossils.

Lungfish were widespread in the freshwaters of the world at the beginning of secondary. Helvetic-Australian study shows that it is in these times that distant line of lungfish is individualized and managed to survive until today in the form of a single species living in Australia.

This discovery provides novel arguments in favor of the protection of lungfish. According to Lionel Cavin and Anne Kemp, "we must now consider the fish as a living fossil part of our global heritage of biodiversity." It now appears particularly urgent to protect Neoceratodus forsteri, the endemic Australian species of about 120 cm long is weakened because it does (on) lives only in four small watersheds in the region of Brisbane (Queensland ). To preserve the unique Australian lungfish, it is essential to better manage the development and operation of waterways around Brisbane, a high growth area and among the most densely populated areas of Australia.

This study shows that paleontology, science based on the study of extinct for millions of years, can lead to very current issues related to the future of biodiversity.

The Australian lungfish Neoceratodus forsteri in the process of breathing air. Lungfish have both gills and lungs, which allows them to breathe in water as in the air. © Anne Kemp

2007. A new Thai Mesozoic lungfish (Sarcopterygii, Dipnoi) with an insight into post-Palaeozoic dipnoan evolution. Zoological Journal of the Linnean Society. 149: 141–177. [[Fulltext]]

http://www.ville-ge.ch/mhng/presse_2011_dipneuste.php

Progress in Jurassic studies in Thailand in 2006 and early 2007

http://www.nigpas.ac.cn/IGCP506/506pro/506proshow.asp?pro_id=72