Marshal Hedin Lab

My collaboration with Jeff Shultz (Univ of Maryland) and his immensely talented PhD student, Mercedes Burns, has been quite excellent. Most recent paper available here

Thanks to Jiří Král for involving me in this research!!

Donated a few SDSU insects to a budding young biologist, helping her pursue her dreams

left to right: Shahan Derkarbetian, Kristen Emata, Erika Garcia, Molly Hedin, Marshal Hedin, Jim Starrett

Just back from a Springbreak collecting trip with a crew from SDSU and UC Riverside.  We traveled to the western foothills of the southern Sierra Nevada Mountains in California, starting in Tuolumne County, and ultimately winding (literally!!) our way down to Kern County. We were mostly after Laniatores harvestmen, particularly members of the phalangodid genus Calicina.  Calicina is a truly remarkable genus, with many species, most of which are short-range endemic taxa.  Almost all of these species were described by Darrell Ubick & Tom Briggs, researchers from the California Academy of Sciences. Below is a screenshot from the Ubick & Briggs revision showing microendemism observed in the Sierras.  Similar patterns are found in the Coast Ranges!!

from FIG 19, Ubick & Briggs, 1989. The harvestmen family Phalangodidae. 1. The new genus Calicina, with notes on Sitalcina (Opiliones: Laniatores). Proceedings of the California Academy of Sciences, 46(4): 95-136.

Kristen Emata, a MS student in the Hedin lab, is interested in the evolutionary and biogeographic history of Calicina, and aims to tackle these questions from a molecular phylogenetic perspective.  Our collections of fresh samples from this recent fieldwork will help greatly in this endeavor.

Calicina from near Pine Flat Reservoir, Fresno County

In addition to Calicina, we found other nice CA endemic harvestmen, like Megacina and Enigmina.  Of course, many other excellent Californian taxa were encountered.  For some reason, I have a special place in my heart for diplurans.  Maybe because many of these species are also low-dispersal, short-range endemics. 

Neat

New paper just published on “Early View” at Molecular Ecology with co-authors Jim Starrett and Cheryl Hayashi from UC Riverside.  I’ll call it “Atypoides II”, although the species is now officially known as Antrodiaetus riversi.

This research follows from our earlier work on this “species”, good old Atypoides I, also published in Molecular Ecology.  Many new insights in this paper – more gene data and much denser geographic sampling allows us to resolve what appear to be eight cryptic species and many really neat Californian biogeographic patterns. The neatest is perhaps the unexpected “trans-valley” connections that we find between spider populations north of Sacramento, and those down near Monterey.  In at least one clade the patterns are pretty crystal clear.  I’ll let you read the paper to learn how this pattern may have originated.

Our work continues on this group, as we’re now writing papers about fine-scale biogeographic patterns in the Bay Area, and papers to formally describe the cryptic species.  To quote from the paper: “Burrowing mygalomorph spiders are roughly analogous to immoveable objects (e.g., rocks) in an evolving landscape. These objects themselves move very little, but are sometimes carried passively by external forces.”

And to quote from Norman Maclean – “Eventually, all things merge into one, and a river runs through it. The river was cut by the world’s great flood and runs over rocks from the basement of time. On some of those rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs. I am haunted by waters.”

Ha, I am haunted by giant mygalomorph spiders

Just returned from an excellent trip to the southern Appalachians!  The primary goal was to collect samples of the federally-endangered Spruce-fir moss spider (Microhexura montivaga) for Illumina NGS transcriptome work.  From these transcriptomes we’ll develop rapidly-evolving genetic markers for downstream population genomics of all known metapopulations. We’re interested in levels of genetic variation within and among metapopulations, patterns of genetic connectivity, and the possibility of cryptic divergence.

Spruce-fir moss spider (Microhexura montivaga), in habitat

This research is derived from a collaboration with Dr. Fred Coyle, retired Biology Professor from Western Carolina University, and Sue Cameron, Endangered Species Biologist with the USFSW at Asheville.  I personally received a huge amount of help on the last trip from Dr. Jason Bond of Auburn University, who hauled me around the mountains, helped collect spiders, and facilitated RNA extraction from the spiders.  And I can’t thank Fred enough for putting us up, showing us spiders, and providing general inspiration!

(L to R) Sue Cameron, Fred Coyle, Jason Bond – enjoying lunch on a fine October day near Clingman’s Dome

Please watch this excellent video, made by Gary Peeples of the USFWS Asheville, to learn more about the project!!