2 4 Fish 8 (Ate)

[digit]

Still fossil hunting indoors during the summer (and the pandemic) amusing myself (and helping the FLMNH) by picking through micro-matrix from the Montbrook dig site in Florida. I've made some other posts featuring the interesting micros I've been finding to try to share a bit of the world of micro-fossils with a wider audience (Florida has more than megalodon teeth).

 

I was picking through a sample of Montbrook micro-matrix. It was collected back in 2018 and was subsequently washed, dried, and sat in a zip-top bag for years awaiting someone to spend about a dozen hours picking through it for interesting specimens. In addition to the monotony of the very abundant common fossil types (fish verts, fish teeth, gar scales, Rhizoprionodon and Dasyatis teeth) my efforts are occasionally rewarded by spotting something out of the ordinary. Sometimes the novelties are just a rarer type of previously seen fossil--a tiny ray dermal denticle the size and shape of an asterisk * or a pretty little serrated Galeorhinus (Tope Shark/Houndshark) tooth. What really makes the long hours pay off is when I encounter a good mystery.

 

Some of the mystery finds are only mysterious to me as they are answered promptly by Richard Hulbert when I send him micro-photographs of some "unknown". I am slowly crawling up the learning curve and broadening my knowledge of the micro-fossil types being found at the Montbrook site. The real fun happens when I get something that's a stumper--a real novelty for the locality.

 

The Montbrook micro-matrix material has a large amount of marine (and freshwater) fish material hiding in it. There are teeth from drum, barracuda, porgy, pinfish and several other marine fish families found floating loosely in the matrix. Tiny button-shaped teeth that resemble those from drums are likely the pharyngeal teeth from wrasses. One of the former mysteries that I now have locked into my set of search images is the tiny (only a few millimeters across) pharyngeal tooth plates for a small species of wrasse. Here's one I found which was full of these little button teeth.

 

 

About two weeks ago I spotted an unusual little specimen in my picking plate. I could tell from the bone structure that it was "fishy" (in a good way ) but the attached tooth type was something new that I had not encountered before. I could see that this piece was a (mostly) complete lower left quarter jaw--you can see the zipper-like symphyseal suture at the midline of the lower jaw indicating that it was not fragmented and there would be no additional teeth expected in this portion of the jaw.

 

   

 

My first thoughts about fishes I knew that had a single tooth in each quarter jaw led me to think about parrotfishes but this was quickly dismissed because I knew that parrotfish "beaks" were composed of tiny tooth plates which are continuously added from the base as the plates wear and break-off on the occlusal surface while the fish feeds by scraping algae from the surface of the substrate. BONUS FACT: Parrotfishes ingest a large amount of calcium carbonate (old coral skeleton) while feeding and the majority of tropical white sand beaches are in fact composed primarily of parrotfish poop.

 

 

Richard forwarded my photographs to a student who specializes in osteichthyan (bony) fishes and I went back to picking more micro-matrix. I had a feeling that the answer would be blindingly obvious in hindsight. Had I thought about it for a moment or two more I probably could have arrived at the answer myself but so many of these mystery finds turn out to be something unexpected that I just trusted that an expert would soon solve the mystery for us. Our fishy expert was in the process of a long cross country move to continue her education at UC Berkeley but before long we got our answer--as obvious as I'd predicted.

 

In her opinion the jaw piece belonged to a member of the order Tetraodontiformes and likely in the family Tetraodontidae (pufferfishes). The answer is right there in the scientific name (Greek, tetra = four + Greek, odous = tooth, teeth) referring to the 4 large teeth fused into a beak-like structure for feeding on hard shells of crustaceans and mollusks.

 

A little bit of searching online quickly turned up images that closely matched my find confirming this diagnosis.

 

 

A related family in the Tetraodontiformes is the Diodontidae (known as porcupinefishes, balloonfishes, blowfishes but also confusingly as pufferfishes). The mouth plates for this family are fused into two plates, upper and lower (Greek, di = two + Greek, odous = tooth, teeth) and are relatively common finds in the Florida fossil record. Anybody who has hunted the Peace River long enough has encountered at least one of these solidly constructed mouth parts with stacks of tooth plates edged in fine maxillary teeth.

 

@Harry Pristis has a fine example of Florida finds in his library of images. There are copious additional images available online with a simple search.

 

 

 

 

These diodontid tooth plates also occur occasionally in the Montbrook micro-matrix but it appears that the tetraodontid jaw specimen likely represents a new family group for the Montbrook faunal list. It is great fun when a tiny find starts as a micro-mystery, serves as a learning example to expand my knowledge base, and finishes by expanding the envelope about what is known of the taxonomic diversity of the site.

 

Cheers.

 

-Ken

 

[Kane]

4 minutes ago, digit said:

 

Parrotfishes ingest a large amount of calcium carbonate (old coral skeleton) while feeding and the majority of tropical white sand beaches are in fact composed primarily of parrotfish poop.

 

 

It's a wonder that isn't part of the marketing for luxury resorts in the Caribbean!  

[digit]

It's in the fine print that nobody reads.

 

 

Cheers.

 

-Ken

[Al Dente]

Between the Tetraodontidae and Diodontidae is Triodontidae, the three tooth puffers. Here's a photo from wikipedia of Triodon macropterus. It has two upper teeth similar to Tetraodontidae puffers and a fused lower tooth plate. It's tooth plates can be found as fossils dating back to the Eocene.

 

 

[digit]

Wow! Mind blown!

 

I've been familiar with species from both the Diodontidae and Tetraodontidae which I frequently encounter while diving in various parts of the world. This wildly keeled version of a puffer was off my radar screens (till now). It appears to have a relatively wide distribution throughout the Indo-Pacific (and apparently even over into the eastern Pacific). I wonder why I've never encountered it before--possibly not very common throughout its range. Something new to keep an eye out for while diving.

 

https://en.wikipedia.org/wiki/Threetooth_puffer

 

 

Cheers.

 

-Ken

[EscarpmentMary]

Thank you! An interesting read! Your Diodontidae , makes me think of Placoderms which probably means I spend way too much time in the Silurian period !

[Ludwigia]

@digit Thanks for this very informative post!

[digit]

I have nowhere near the depth of knowledge of many of the members here on the forum. When I do come by a bit of knowledge I enjoy sharing it here.

 

 

Cheers.

 

-Ken

[crabfossilsteve]

That was a very interesting read and that pic of the puffer fish is really wild compared to the puffers I've caught in the past.  Thanks for the post.