I was originally hoping to write a post today detailing all of the creative outreach activities that the ichthyology collection has participated in the past several months, culminating in our Nature Fest that was scheduled for this last weekend. However, the rapid spread of the coronavirus, and the importance of a unified community response to slow this spread, means this post will not be about community outreach, but rather our commitment as a museum to joining the efforts of the community to minimize the spread of Covid-19. Nature Fest and all other events at the NHMLA have been postponed, and the museum is closed to the public until further notice. Likewise, our collections are closed to researchers during this time, and loans to other institutions may be delayed as well. If you are sending a loan back to us, please check with either Todd or myself prior to doing so to make sure we will be there to receive the loan. Please see the official announcement below, and check in with the NHMLA website for up-to-date information. We will get through this as a community, and once we do we will be back with more fun outreach events, new scientific discoveries, and fun fish facts. In the meantime, wash your hands, follow advice from the CDC, and stay safe.
Just out this week, a new publication in collaboration with Luiz Rocha at the California Academy of Sciences and Prosanta Chakrabarty at the LSU Museum of Natural Science. Together we sequenced the mitochondrial genomes of two species of sawtail surgeonfishes. This genus of surgeonfishes isn't as common to come by as many of the others. Furthermore, it is the only genus of surgeonfishes that didn't have their mitochondrial genomes sequenced already. The addition of these two genomes allows us to examine the family as a whole, and can be used as a resource for future researchers. The publication is open access (freely available to download) and can be found in the journal Mitochondrial DNA Part B. Check it out and let me know what you think!
At the beginning of November I represented the NHMLA on a joint expedition to Costa Rica. This trip was led by Dr. Caleb McMahan at the Field Museum of Natural History in Chicago, and also included Dr. Arturo Angulo from the Zoology Museum at the University of Costa Rica. This expedition targeted freshwater drainages and brackish water habitats along the Atlantic slope of the country. We were generally collecting species we came across to observe variation and turnover in species assemblages as we sampled different river drainages along the coast, but we were also targeting several species that are the focus of ongoing research projects. As soon as we landed, however, the rain started pouring, and continued to do so for the first half of the trip. While we pressed on and sampled in the rain, the water levels of the streams and rivers we were sampling in were high, making it difficult to get certain species. Additionally, this created problems when we went to sample brackish waters, mainly in the sense that we couldn't find any brackish habitats... Even at the mouths of rivers, the outflows were so strong that all the water we tested with a salinity meter was completely fresh.
This may sound like a horrible setup to a trip, but in reality everything turned out great in the end. The rains stopped, and we had clear skies for the second half of the trip. Additionally, we met up with a friend of Arturo's, Maribel Mafla Herrera, who works the non-profit association ANAI. Maribel was gracious enough to not only show us some of the fishes in southern Costa Rica, but as part of the ongoing biomonitoring that ANAI does she brought out her fish electroshocker, which helped us see a lot of species that we wouldn't have seen just using our seines and nets. At the end of the trip we spent a day in San Jose at the University of Costa Rica processing all of the fishes we collected and exploring their fantastic ichthyology collection. In the end, it was an extremely successful trip. We managed to find all of the target species we were interested in, collected a diversity of fishes, and got fantastic live-color photos of fishes that haven't been photographed live before. A huge thanks to all of those that helped this expedition, with special thanks to Caleb McMahan and the Field Museum, Arturo Angulo and the University of Costa Rica, Maribel Mafla Herrera, and ANAI.
After a busy last few weeks of summer that included the annual Joint Meet of Ichthyologists and Herpetologists and moving across the country, I have officially started as Assistant Curator of Ichthyology at the Natural History Museum of Los Angeles County! I will be looking after the Robert J. Lavenberg fish collection, which houses specimens collected across the world. I am extremely excited to start this position, and can't wait to see what lies on those shelves. If you happen to be in the area, please stop on by!
Hot off the press: a new collaborative publication led by Chris Kenaley on remoras just became public this week! Remoras are a fascinating family of fishes, as they have a modified dorsal fin that acts as a suction disk, allowing them to attach to other fishes, turtles, or marine mammals. These hitchhiking fishes are also sometimes called suckerfishes due to this adaptation, and in this study we took a variety of approaches to understand the most that we could about how this behavior evolved. This included determining the relationships of the eight remora species, using microCT scans to get extremely detailed resolution of the suction disk, examining what animals all of the remora species were attaching to, and then finally figuring out how minute differences in the hosts effected how remoras could attach to them. Overall we recovered two main groups of remoras: a group of species commonly seen around reefs and those that are more pelagic. These groups of species differ in the number and type of host species that they hitchhike on, and finally these host differences seem to be associated with skin roughness and the hydrodynamic regime of the host, and the ability of the suction disk to adhere to that particular skin. If you'd like to read the specifics, the publication is out in Integrative Organismal Biology, an open source journal so anyone can read it for free!
The Indo-Pacific is the place to be if you're interested in coral reef critters. Sure, coral reefs exist all over the world within tropical latitudes, but the epicenter for biodiversity is the Coral Triangle, an area that spans roughly between the Philippines, Indonesia, and east towards Papua New Guinea. Understanding how the Coral Triangle formed, or why it is so diverse requires a broader approach that looks across both the Indian and Pacific Oceans. Quantifying evolutionary dynamics in the Indo-Pacific, however, is extremely challenging. This is foremost because the scale of the two ocean basins. Together, the portions of the Indian and Pacific Oceans that are considered to be part of the Indo-Pacific span roughly 180º longitudinally (aka half the planet)! To study the distribution, population dynamics, and history of species across this massive expanse takes time, dedication, and a big team of people.
Over the past two decades, independent labs have published a variety of population-level genetic studies across the Info-Pacific. These studies have focused on fishes, corals, or marine invertebrates, but were all largely independent of one another. In an effort to gain a more wholistic understanding of what's going on, several forward thinking scientists decided to pool all of their data and invite others to do so as well. Enter stage right: Diversity of the Indo-Pacific Network, or simply, DIPnet. While I could come up with my own way of describing it, the DIPnet mission statement puts it best: "DIPnet was created to advance genetic diversity research in the Indo-Pacific Oceans by aggregating (published) population genetic data into a searchable database so that original datasets can be utilized to address questions concerning conservation of marine biodiversity." This network and team of scientists finally allows us to look for more general patterns that are shared across life in the oceans.
I am proud to be a part of this network, and extremely happy that the first publication from this massive effort has just been published in Global Ecology and Biogeography. Led by the talented Eric Crandall, this study aims to see if there is a correlation between processes acting within species, and between them throughout this region. To do this we looked for shared genetic breaks between regions, and then compared those to previous biogeographic schemes that have been hypothesized over the years. The previous hypotheses were based on species distributions, and therefore reflect processes acting on deeper evolutionary time scales, so by comparing population-level genetic data to these species-level biogeographic breaks we could see if there are ongoing processes that generate diversity over a variety of time scales. The short answer is that while some large-scale patterns hold true, there really isn't a strong connection between population and species-level processes in the 56 species included in this study. If you want to know why, please go check out the paper. It's open access, so anyone can read it! Huge thanks goes out to Eric, all of the co-authors, and all of the people who contributed their data to DIPnet, as this paper wouldn't have been possible without them. Hopefully this is the start of many publications and fruitful collaborations that together will help us understand the diversity of the Indo-Pacific, and coral reefs in general.
I am happy to announce that my collaboration with Christopher Burridge at the University of Tasmania, and Prosanta Chakrabarty at Louisiana State University is finally published! This study uses a genomic approach to determine the evolutionary relationships among fishes in the suborder Cirrhitoidei, which contains hawkfishes (Cirrhitidae), marblefishes (Aplodactylidae), kelpfishes (Chironemidae), trumpeters (Latridae) and morwongs (Cheilodactylidae). This was my first foray into genomic methods and I started the lab work for this early on in my PhD. Slowly, the project grew until we had sampled almost every single species in this group, which has allowed us to confidently make taxonomic revisions. When I started this project it was known that Cheilodactylidae was not monophyletic, but no revisions had ever been made. Late last year the first major revision of this group was made by a Japanese team of researchers led by Katsuya Kimura using a morphological approach. Our study complements that study by adding in additional taxonomic sampling and genomic data. Hopefully the two of these papers together will settle any taxonomic confusion within this group of fishes.
New publication just out this week in Ecology and Evolution! Many species can easily be distinguished by outward appearances, either by differences in body shape, color, or other patterns. However, outward appearances can be deceiving, and sometimes the old adage "don't judge a book by it's cover" can apply to species as well. This is exactly what we found when we looked more closely at two surgeonfishes in the eastern Pacific. These two species are easily distinguished by the presence or absence of dark spots covering the body. Earlier work that I had published on this group hinted that there was something strange going on with these two species. So, I decided to go back and revisit the eastern Pacific. Working with a great group of collaborators (Moisés Bernal, Eva Salas, Erica Kenworthy, and Prosanta Chakrabarty), we were able to show through a variety of approaches that these two species are in fact, one. What causes some individuals to have dark spots and other to not have the? That's a great question, and one we still don't know the answer to. However, this research does highlight how speciation can (although clearly not always) happen along the coasts of the tropical eastern Pacific. It's an open access article, so go check it out if you're interested!
New paper out this week led by the multi-talented Fernando Alda. In this paper we look at a very hard problem in phylogenetics: how to accurately determine relationships in groups that rapidly diverged a long time ago. These short branch lengths at deeper nodes in the tree cause a variety of problems when analyzing even the largest genomic datasets. In this paper we used several different filtering methods and recover a novel relationship for gymnotiform fishes (weakly electric knife fishes found in the Neotropics). If you're interested take a look over at the Systematic Biology website and let me know what you think!
I threw together a short animation using one of the scans from my recent trip to Friday Harbor. Hope you like it!