Yesteday someone posted a Youtube video in a thread of the JW movie from Planet Dinosaur on Spinosaurus when fishing. I was intrigued when I heard that, like crocs, it had some mechanosensors in the snout to sense waves of incoming prey. The reason is because mechanosensors and electroreceptors of that sort come from cranial lateral line placodes in fish and amphibians, and were lost in amniotes. I had a look at an excellent paper on croc integumentary sensory organs (ISOs) and found out that they come from the trigeminal nerve. The cellular/tissular structure of ISOs doesn´t seem like neuromasts, but I don´t recall another example of amniote lateral line-like mechanosensors. This makes me wonder if amniote placodal and/or neural crest derivatives in the head have the potential to evolve a lateral line-like system in the head as in non-amniote vertebrates when coming back to water. Don´t know if marine reptiles also had these mechanosensors more widespread in the head. jeb.biologists.org/content/215/23/4217.full
Posted on: Thu, 27 Nov 2014 08:31:23 +0000
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