Dentition and dentigerous bones in juveniles and adults of Polypterus senegalus (Cladistia, actinopterygii)

Clemen, Günter; Bärtsch, Peter; Wacker, Karin

doi:10.1016/s0940-9602(98)80076-9

Cited by 31 publications

(37 citation statements)

References 20 publications

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“…In the present study we concentrated on the teeth of the lower jaw, as this allows us to compare our data to previous studies (Clemen et al., ; Wacker et al., ; Vandenplas et al., ). In the juvenile specimens of P. senegalus , the dentary, coronoid 1 and coronoid 2 are well‐developed.…”

Section: Resultsmentioning

confidence: 94%

A comparison of the larval and juvenile dentition in Polypterus senegalus

2014

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Summary Polypterus senegalus is a freshwater fish belonging to the earliest diverged group of the actinopterygian lineage with currently living representatives. Its dentition has been well characterized in terms of distribution and shape of teeth in different life stages. Additionally, structural features of the first‐generation teeth have been briefly described. However, at present it is not known how the primary dentition is patterned and if this pattern is similar to that found in juveniles. In this preliminary study, to answer this question we investigate the tooth pattern of a larval P. senegalus based on serial sections and 3D reconstructions, and compare dental features in larvae and juveniles. Polypterus senegalus passive apterolarvae possess a well developed primary dentition. Dentigerous bones develop either prior to the teeth (dentary, retroarticular), or as an attachment site concomitant with the expanding dentition (coronoid 1). Most teeth are attached and erupted, and thus considered functional, and their pulp houses a blood vessel, two features that contrast with earlier findings. The primary teeth do not display a level of maturation that could reflect a particular order of development. New teeth are added anteriorly, and likely also posteriorly, to allow the tooth row to grow to keep pace with the growing jaw. Replacement teeth are absent at this stage. Thus, the pattern observed in juveniles, with alternate (odd and even) positions displaying a different level of tooth maturation, is not present in the larva. Most strikingly, in the larva, considerable symmetry exists between apparently random patterns on both dentaries, eliciting intriguing questions on left‐right control to be addressed in future studies.

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Section: Resultsmentioning

confidence: 94%

A comparison of the larval and juvenile dentition in Polypterus senegalus

2014

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“…The maxilla lacks the pronounced posteroventral curvature and posterior expansion of Guiyu 5, Psarolepis , onychodonts2930 and early actinopterygians31323334, and in this respect is more similar to porolepiforms35. As in early sarcopterygians, the prearticular extends anteriorly to mesially flank the coronoids52136, differing from the condition in primitive actinopterygians where the prearticular sutures against the posterior margin of the most posterior coronoid3137.…”

Section: Resultsmentioning

confidence: 98%

The largest Silurian vertebrate and its palaeoecological implications

Choo

Zhu

Zhao

et al. 2014

Sci Rep

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An apparent absence of Silurian fishes more than half-a-metre in length has been viewed as evidence that gnathostomes were restricted in size and diversity prior to the Devonian. Here we describe the largest pre-Devonian vertebrate (Megamastax amblyodus gen. et sp. nov.), a predatory marine osteichthyan from the Silurian Kuanti Formation (late Ludlow, ~423 million years ago) of Yunnan, China, with an estimated length of about 1 meter. The unusual dentition of the new form suggests a durophagous diet which, combined with its large size, indicates a considerable degree of trophic specialisation among early osteichthyans. The lack of large Silurian vertebrates has recently been used as constraint in palaeoatmospheric modelling, with purported lower oxygen levels imposing a physiological size limit. Regardless of the exact causal relationship between oxygen availability and evolutionary success, this finding refutes the assumption that pre-Emsian vertebrates were restricted to small body sizes.

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“…The teeth of these three genera are clearly unlike those of Hydrocynus, in that all three are round in cross section rather than labiolingually compressed, and none has the cutting edge with a notch at the base of the crown that is found in Hydrocynus (A.M. Murray, personal observation; see also Roberts 1969, figs. 1, 16, 27;Clemen et al 1998, fig. 7; Murray et al 2010, fig.…”

Section: Remarksmentioning

confidence: 99%

Earliest occurrence of Hydrocynus (Characiformes, Alestidae) from Eocene continental deposits of Méridja Hamada, northwestern Sahara, Algeria

et al. 2016

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Abstract:We here report the oldest remains (teeth) of the African tigerfish (Hydrocynus) from the Oued Méridja and Garet Dermchane sections, Hamada of Méridja deposits, in southwestern Algeria. The tigerfish, a large carnivorous fish today represented by several species in the freshwaters of Africa, was previously found in upper middle to upper Eocene deposits in Egypt and Libya. The remains described here are several million years older, being early to middle Eocene in age, and are associated with other fish elements including lungfish, polypterid, amiiform, possible cichlid, and Alestes and Brycinus material, along with several fish elements that cannot be associated with a specific taxon and some fragmentary amphibian bones. This represents the first detailed description of a freshwater fish assemblage from the Eocene of Algeria, although a short list of fish taxa from Eocene Algerian deposits was previously reported. Furthermore, these new Algerian fossils allow us to assess the hypothesized existence of an east-west or west-east hydrological connection between eastern and western parts of northern Africa. We suggest that the shared presence of tigerfish in the Eocene deposits of Algeria, Libya, and Egypt does not necessarily indicate a permanent (i.e., nonseasonal) connection east-west or west-east among these areas. Rather, the observed faunal similarities could have been the result of seasonal flooding that caused the dispersal of Hydrocynus and associated taxa across coastal flood plains.Résumé : Nous rapportons ici la découverte des plus anciennes dents fossiles représentant le poisson-tigre africain (Hydrocynus) dans les coupes de l'Oued Méridja et de Garet Dermchane, Hamada de Méridja, sud-ouest algérien. Le poisson-tigre, un grand poisson carnivore aujourd'hui représenté par plusieurs espèces dans les eaux douces africaines, avait déjà été découvert dans des sédiments datant de la fin de l'Éocène moyen à supérieur en Égypte et en Libye. Les fossiles que nous décrivons ici sont plus anciens de plusieurs millions d'années, datant de l'Éocène inférieur et moyen, et sont associés à d'autres fossiles de poissons, parmi lesquels des fossiles de dipneuste, de polyptéride, d'amiiforme, de cichlide probable, et des éléments ressemblants à Alestes et Brycinus, ainsi que des ossements de poissons ne pouvant pas être identifiés de manière certaine et des fragments d'os d'amphibiens. Ceci représente la première description détaillée d'une faune de poissons d'eau douce de l'Éocène provenant d'Algérie, bien qu'une courte liste de poissons découverts dans des sédiments de l'Éocène algérien fut précédemment publiée. En outre, ces nouveaux fossiles algériens nous permettent d'évaluer l'hypothèse d'une connexion hydrologique est-ouest ou ouest-est, à travers l'Afrique du Nord. Nous suggérons que la présence de poissons-tigres dans l'Éocène de l'Algérie, de la Libye et de l'Égypte n'indique pas nécessairement une connexion permanente (non saisonnière), mais plutôt que les similarités observées entre ces faunes auraient ...

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Dentition and dentigerous bones in juveniles and adults of Polypterus senegalus (Cladistia, actinopterygii)

Cited by 31 publications

References 20 publications

A comparison of the larval and juvenile dentition in Polypterus senegalus

A comparison of the larval and juvenile dentition in Polypterus senegalus

The largest Silurian vertebrate and its palaeoecological implications

Earliest occurrence of Hydrocynus (Characiformes, Alestidae) from Eocene continental deposits of Méridja Hamada, northwestern Sahara, Algeria

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