Another tiny hingemouth relative: Early Cretaceous Santanichthys

Short one today
as the graphics (Fig 1) tell the tale recovered by the LRT.

Figure 1. Tiny Early Cretaceous Santanichthys enters the pool of relatives for the very strange hingemouth, Phractolaemus. ” data-image-caption=”

Figure 1. Tiny Early Cretaceous Santanichthys enters the pool of relatives for the very strange hingemouth, Phractolaemus.

” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg?w=153″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg?w=523″ class=”size-full wp-image-85094″ src=”https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg?w=584&h=1143″ alt=”Figure 1. Tiny Early Cretaceous Santanichthys enters the pool of relatives for the very strange hingemouth, Phractolaemus.” width=”584″ height=”1143″ srcset=”https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg?w=584&h=1143 584w, https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg?w=77&h=150 77w, https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg?w=153&h=300 153w, https://pterosaurheresies.files.wordpress.com/2024/03/phractolaemus_ansorgii-marcopoloichthys588-1.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 1. Tiny Early Cretaceous Santanichthys enters the pool of relatives for the very strange hingemouth, Phractolaemus. Over time the big heads of the Mesozoic ancestors evolved smaller in the extant hingemouth.

Earlier
tiny Middle Triassic Marcopoloichthys (Fig 1) also nested with the hingemouth, Phractolaemus.

According to Wikipedia,
“The hingemouth (Phractolaemus ansorgii) is a small freshwater fish that is found only in west central Africa, the sole member of the subfamily Phractolaeminae of the family Kneriidae. The mouth can extend like a small trunk, thus the name, and has just two teeth, both in the lower jaw.”

Santanichthys diasii 
(Silva Santos 1958; Filleleul and Maisey 2004; Early Cretaceous; 3cm; DGM-DNPM 647P) was a tiny Santana Formation fish considered the oldest characiform and otophysan. Here it nests with Spinocaudichthys. It is the earliest appearance of a Weberian apparatus, a sound amplifier that connects the swim bladder to the auditory system. Note the extremely deep mandible. In the LRT these taxa nest with sea horses and flying fish, among others.

A solution to the Phractolaemus (hingemouth fish) problem

References
Boulenger GA 1901. Diagnoses of new fishes discovered by Mr. W. L. S. Loat in the Nile. Annals and Magazine of Natural History, Including Zoology, Botany and Geology, Being a Continuation of the ‘Magazine of Botany and Zoology’, and of Louden and Charlesworth’s ‘Magazine of Natural History’, Series 7 8: 444-446.
Grande T and Poyato-Ariza FJ 1999. Phylogenetic relationships of fossil and Recent gonorynchiform fishes (Teleostei: Ostariophysi). Zoological Jounial of the Linnean Society (1999), 125: 197-238.
Poyato-Ariza FJ, Grande T and Diogo R 2010. Gonorynchiform Interrelationships: Historic Overview, Analysis, and Revised Systematics of the Group.In: Grande, T., F. Poyato-Ariza & R. Diogo (eds.), Gonorynchiformes and ostariophysan relationships – a comprehensive review, Science Publishers and Taylor & Francis (Oxford, UK): 221-231.
Silva Santos R 1995. Santanichthys, novo epiteto generico para Leptolepis diasii Silva Santos, 1958 (Pisces, Teleostei) da Formacao Santana (Aptiano), Bacia do Araripe, NE do Brasil. Anais da Academia Brasileira de Ciencias 67:249–258.

wiki/Santanichthys
wiki/Hingemouth
wiki/Gonorynchiformes/