Watsonulus and its eel-like descendants

Increasingly eel-like descendants
mark Early Triassic Watsonulus and extant Channa in the large reptile tree (LRT, 2312 taxa). These taxa share a larger number of traits despite their chronological and morphological difference from each other.

Again the loss of the circumorbital ring and pelvic fins tended to attract the eel-like clade members toward eels and away from basal members.

Figure 1. Early Triassic Watsonulus gave rise to smaller and smaller eel-like taxa, including Channa, Cetostomus, Aenigmachanna, Symbranchus and Monopterus. ” data-image-caption=”

Figure 1. Early Triassic Watsonulus gave rise to smaller and smaller eel-like taxa, including Channa, Cetostomus, Aenigmachanna, Symbranchus and Monopterus.

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Figure 1. Early Triassic Watsonulus gave rise to smaller and smaller eel-like taxa, including Channa, Cetostomus, Aenigmachanna, Symbranchus and Monopterus.

According to Wikipedia,
“Watsonulus belongs to Parasemionotidae, a family of early neopterygians closely related with halecomorphs.”

In the LRT Watsonlulus does not nest with Parasemionotus,
a bony fish basal to lobefin coelacanths in the LRT.

Watsonulus eugnathoides
(originally Watsonia Piveteau 1935; Olsen 1984; Early Triassic; 7cm skull length, 30cm long) is a traditional parasemionotid fish here related to the extant muskellunge, Esox, and the extant snakehead, Channa, another predatory freshwater bony fish. Note the large diamond opening between the nasals and frontals in dorsal view. The parietals are separated laterally by the postparietal. The marginal teeth are tiny. The pectoral fins are much larger than the phylogenetically disappearing pelvic fins.

References
Olsen PE 1984. The skull and pectoral girdle of the parasemionotid fish Watsonulus eugnathoides from the Early Triassic Sakamena Group of Madagascar, with comments on the relationships of the holostean fishes. Journal of Vertebrate Paleontology 4(3):481–499.
Piveteau J 1935. Palkontologie de Madagascar. XXI. Les Poissons du Trias infkrieur. Contribution 2 l’ktude des actinoptkrygiens. Annales de Pal6ontologie 23:8 1-1 80.

wiki/Watsonulus