Miguel Montalvo
Ph.D. Student
Email:
[[v|mmontalvo]]
Phone:
804-684-7544
Office:
Fisheries Science Laboratory 110
Advisor:
{{https://www.vims.edu/about/directory/faculty/hilton_ej.php, Dr. Eric Hilton}}
About me
As a person whose background is in marketing and communications, I strive to leave my mark by using media to get people excited about exploring the natural world. I often use microphotography to capture small objects and document their details as stills or film. I also enjoy wildlife photography and videography in the field. I create and have created content that has been featured as part of scientific stories in social and legacy media. Some of those include VIMS, The Billfish Foundation publications, The Smithsonian National Museum of Natural History, Mote Marine Laboratory and Aquarium, The Florida Wildlife Research Institute, and The BBC.
My work at VIMS is centered around morphology and systematics of fishes. I am looking at anatomical features (bones, muscles, etc.), describing them, and asserting evolutionary pressures and relationships derived from those analyses. I am passionate about that work because I get to work with real specimens and use techniques that are often visually striking (see some images below).
Dissertation work
Billfishes and fishes with a billI am investigating the evolution and development of billfishes. This group includes very charismatic fishes such as the marlins, swordfish, and sailfish. These animals are fascinating because, among other things, they have an elongated rostrum – their “bill”. They are also very fast swimmers and fast growers. Some can reach enormous sizes – like the blue marlin (Makaira nigricans) from the following photo.
This is me at a fishing tournament with an enormous blue marlin - this was my first time seeing a fish of this size! We collect data from tournaments like The MidAtlantic to help us assess the health of fish stocks. Some of these fishes are sometimes donated to us and become part of the Nunnally Ichthyology Collection that houses specimens that can be used by researchers all over the world.
As part of this project, I am investigating the larval stages of those fishes to find out how their teeth develop. Early-life dentition of these fishes is very different from their adult form. While larval billfishes have very sharp, discreetly placed teeth, their adult counterparts have sort of tooth plates with very closely assembled teeth. Understanding the development of their teeth could help us learn more about diets in some of the more cryptic juvenile stages of these animals. The qualities of the adult fishes could also have material science implications. Lastly, documenting this process could give us more clues about evolutionary relationships of billfishes to other percomorph fishes (percomorphs are a large clade of bony fishes, they make up the vast diversity of all the fishes). Hypotheses about these relationships have been contentiously debated for decades.
This the larva of a swordfish (Xiphias gladius). It has been cleared and stained to show the bony and cartilaginous features.
The second part of my dissertation involves investigating the fossil history of billfishes. Specifically, the description of some early billfish fossils from the middle Eocene of Pakistan. Although these fossils have been attributed to the early billfish family †Palaeorhynchidae it is still not clear if this assessment is correct. Furthermore, there are still some doubts about how closely †palaeorhynchids are to billfishes, and if they should be included within Xiphioidei (I like to use this group to include all billfishes, some other researchers use Istiophoriformes).
The first impression of the fossil material was a bit underwhelming. The fossils were found in a limestone lithography and from afar they looked like mostly flattened impressions. I am happy to report, though, that upon closer inspection they have plenty of detailed anatomical features, including some awesome surprises! Most of them are actually body fossils and the ones featuring skulls are fascinating.
This is a mosaic of many close up images of one of the alleged †palaeorhynchid fossils that I am studying. Although it might not seem like much, there are a lot of features observable here and even more so when looking at this specimen under a microscope.
The third and last chapter of my dissertation involves investigating other fishes that have elongated rostra – think needlefishes. There may be surprising evolutionary pressures leading to the formation of those long snouts amongst distantly related groups of fishes. I am using museum specimens to measure rostral elongations on thousands of specimens. I am using other techniques like clearing and staying and CT scanning to explore the anatomical building blocks of the elongations.
Updates
November 2024
The dermestids have a new home officeThis month I was able to finish a project that was two years in the making. The dermestid beetles - YES BEETLES - that we use to clean fish skeletons needed a new enclosure. Part of the reason for this is that the billfishes that I am preparing were too big for the previous one. This new one has more space for larger specimens and is easier to access and maintain.
Dermestid beetles (Dermestes maculatus) can be found on all the continents except for Antarctica. This is a close up of Shirley, they are one of the hardworking beetles in the new colony.
Another reason for this new enclosure is to make the process more visible. For outreach purposes as well as for monitoring this is an advantage. The transparent polycarbonate that the tank is made of allows for complete views of the inside. It is very interesting to see adult and larval dermestids go about their day munching on the specimens. I have to say, though, that for someone that works in the lab all day this new setup is very distracting – like a beetle reality show!
I had never worked with 1/2in thick polycarbonate before, but I am surprised at how versatile this material is. When I started cutting the material to size – it came in as large 8x4ft sheets – I used a circular saw. While this worked out to do the approximate sizing of the parts to be assembled, the finish on the cut ends was very rough. I moved to using a router to finish the cuts. It worked so much better than I was expecting. The routed edges were almost indistinguishable from the factory cuts. I was also able to make millimeter-scale changes to the size of the panels to ensure fitment. Using the router, I was also able to drill a large hole on top of it to fit an exhaust fan – beetles and their fishy food can be a bit stinky, and you need good airflow so that no mold grows on the skeletons being cleaned. For this I used a lid as a template. I slowly lowered the router bit as I made passes around the lid – it worked flawlessly! Polycarbonate’s high strength and ductility made it a very easy material to work with.
This is the empty enclosure complete with door. The toggle clamps on the sides keep the door locked by putting pressure against the main body of the enclosure.
Right before Thanksgiving, after I was done with constructing this enclosure, I moved several skeletons into the enclosure: a large blue marlin head (the original fish weighed over 400lb), a big eye tuna spine and caudal fin, and those of another blue marlin and three smaller white marlins. A few weeks out from that date, and the dermestids seem to be thriving in their new digs. There are lots of beetle droppings, molts, and larvae crawling all around the specimens being cleaned. I think that they’ll need a couple of months to finish their current task, but it might be sooner.
This is the finished enclosure with some specimens inside. The front door is removed.
Now that the enclosure is built, I want to make a wooden cradle so that we can move it around. I always enjoy seeing the beetles work, and I think that other people will as well. I think that bringing the colony to display at open-houses or other events will be very rewarding. My advisor suggested gilding it, Ark of the Covenant style – what do you think?
By the way, I want to thank my friend and colleague Larson Palmgren for helping me with building this enclosure.
The Ark of the Beetles!
Research interests
Larval fishes
Baby fishes are fascinating, they are tiny, and derpy, and they—most of the time—look nothing like their adult parents. As it happens, VIMS has a long legacy of larval fishes research which makes it the perfect place to get more acquainted with these amazing animals. So, after pestering some of my colleagues who are actively researching them, I am helping them to sort and document some larval specimens.
Because these specimens are so tiny, you use a stereo microscope to look and sort through the samples. I am using my own Leica scope, with a phototube attached to a my Nikon mirrorless to take images - and sometimes videos. I hope you are as captivated by these specimens as I am :)
