- Author: Kathy Keatley Garvey
They share a name, for one thing.
When evolutonary biologist-taxonomist Chris Hamilton, a former doctoral student at Auburn University, Alabama, and now on the University of Idaho faculty, led a research team near the site of California's Folsom State Prison to look for tarantulas, he discovered a new species, solid black in color.
He named it Aphonopelma johnnycashi after Johnny Cash, the legendary country singer known as "The Man in Black."
Fast forward to this week:
Hamilton, now assistant professor in the Department of Entomology, Plant Pathology and Nematology, will speak on tarantula diversity when he presents a virtual seminar at 4:10 p.m., Wednesday, April 21 to the UC Davis Department of Entomology and Nematology. His title: "Understanding Aphonopelma Diversity across the Madrean Pine-Oak Woodlands Hotspot by Integrating Western Science and Traditional Ecological Knowledge (TEK)." Click on this link to access the seminar.
Hosting the seminar is Jason Bond, the Evert and MarionSchlinger Endowed Chair in Insect Systematics, UC Davis Department of Entomology and Nematology, and Hamilton's major professor at Auburn University. Hamilton received his doctorate in evolutionary biology from Auburn University in 2015, after earning his master's degree in biology in 2009 from the University of Texas at Arlington.
"Dr. Hamilton does great work on terrestrial arthropods with an emphasis on mygalomorph spiders (trapdoor spiders, tarantulas and their kin)," Bond commented.
Hamilton's abstract: "Within the world of theraphosid systematics, the genus Aphonopelma has received considerable attention in recent years. But despite these efforts, the group's diversity remains poorly understood in the Madrean Pine-Oak Woodlands Hotspot located in the southwestern United States and northern Mexico--an ecoregion known for its exceptional biodiversity and endemicity. It has long been thought that Aphonopelma was a 'taxonomic and nomenclatural nightmare' because across their distributions, similarly sized species are often frustratingly similar morphologically. This is all too obvious when examining populations in the Madrean Sky Islands and Sierra Madre Occidental, as their shared evolutionary history and divergence in similar isolated habitats has produced very similar phenotypes. This work looks to employ an integrative approach for delimiting species that incorporates information from morphology (traditional and advanced techniques) and molecules (phylogenomics), as well as data on ecology (niche, distribution, and behavior) and how Traditional Ecological Knowledge (TEK) of the Apache and Tohono O'odham peoples may help piece the puzzle together. As we continue to investigate some of the more remote and hard-to-access mountain ranges, we have discovered that most independent ranges harbor their own divergent and distinct lineages that may represent new species."
Hamilton received his doctorate in entomology from Auburn University; his master's degree from the University of Texas at Arlington; and his bachelor's degree from Western Kentucky University.
Hamilton's naming of the new tarantula species drew widespread interest. Lindsay Miles of Auburn University's Office of Communications and Marketing wrote a 2016 news release: "The species, Aphonopelma johnnycashi, was found in California near the site of Folsom State Prison, which Cash made famous in his song Folsom Prison Blues. The mature male Aphonopelma johnnycashi measures up to 6 inches across and is generally solid black in color, much like Cash's distinctive style of dress from which his nickname, 'The Man in Black,' was coined."
"Along with the Aphonopelma johnnycashi, Hamilton's study determined there are only 29 species of tarantula in the United States, 14 of which are new to science. Researchers had previously identified 55 species. The new descriptions nearly double the number of species known from the American Southwest, a region described as a biodiversity hotspot featuring frigid mountains and scorching deserts."
The team, Miles wrote, "spent more than a decade searching for tarantulas throughout the American Southwest and studied almost 3,000 specimens, undertaking the most comprehensive taxonomic study ever preformed on a group of tarantulas." The study was part of Hamilton's dissertation, which was funded by two National Science Foundation grants made to Auburn University.
In the news story, Bond, then chair of the Department of Biological Sciences, praised Hamilton as "an accomplished field biologist and taxonomist (who) is also doing cutting-edge genomics research."
Miles pointed out that "Although this is the first time Johnny Cash has been honored by an Auburn researcher, Auburn University professors have garnered national attention in the past for naming celebrities, characters and even President Obama, with a species name. Bond has named species of trapdoor spiders after U2's Bono, actress Angelina Jolie and talk show host Stephen Colbert, to name a few. Jonathan Armbruster, also of the Department of Biological Sciences, made headlines last year when he named a newly discovered catfish species after the Star Wars fan favorite, Greedo."
Cooperative Extension specialist Ian Grettenberger is coordinating the spring seminars and may be reached at email@example.com for any technical questions.
- Author: Kathy Keatley Garvey
Have you ever wondered about sexual size dimorphism in the tropical spiders, the golden orbweavers?
The females are sometimes 10 times larger and 100 times heavier than their male counterparts. And the webs that the females weave are huge--they can be as wide as five feet in diameter.
And, yes, the females cannibalize the males, says Jason Bond, professor and Schlinger Chair in Insect Systematics, UC Davis Department of Entomology and Nematology,
“Sexual size dimorphism (SSD) often seems to be correlated with extreme morphological, behavioral and life history phenotypes in either sex,” says Bond, senior author of a newly published paper in the Journal of Systematic Biology, a peer-reviewed scientific journal published by Oxford University Press on behalf of the Society of Systematic Biologists.
Through phylogenomic (the intersection of the fields of evolution and genomics) and comparative analyses, Bond and his colleagues found that golden orbweavers “ignore biological rules.”
The global team of 11 scientists--from Slovenia, China, Taiwan, Czech Republic and the United States (UC Davis, Smithsonian Institution, University of Idaho, University of Florida and University of Vermont)--unraveled a complex evolution of sexual size and dimorphism and found that Nephilid female gigantism is a “phylogenetically ancient phenotype, over 100 million years old, though their magnitudes vary by lineage.”
The spiders belong to the genus Nephila and family Nephilidae; the members are known for constructing huge or exaggerated webs. The species thrive in warmer regions throughout the world, including Australia, Asia, Africa (including Madagascar) and the America. One species, N. clavipes, is found in southern United States, from Texas to North Carolina.
For the paper, “Golden Orbweavers Ignore Biological Rules: Phylogenomic and Comparative Analyses Unravel a Complex Evolution of Sexual Size Dimorphism,” the team tested two biological rules: Cope's rule and Rensch's rule. Cope's rule postulates that population lineages tend to increase in body size over evolutionary time. Rensch's rule is a biological rule on allometric patterns of male and female size. Neither rule applied to the golden orbweavers.
First, the scientists established the backbone phylogeny of Nephilidae, using 367 anchored hybrid enrichment markers, and then combined these data with classical markers for a reference species level phylogeny.
In conclusion, the scientists proposed a new clade, a group of organisms evolving from a common ancestor. They resurrected the family Nephilidae and proposed the new clade, Orbipurae, to contain Araneidae Clerck 1757, Phonognathidae Simon 1894, new rank, and Nephilidae.
The researchers proposed “taxonomic changes based on the criteria of clade age, monophyly and exclusivity, classification information content, and diagnosability. Spider families, as currently defined, tend to be between 37 million years old and 98 million years old, and Nephilidae is estimated at 133 million years old, thus deserving family status.”
“Nephilid female gigantism is a phylogenetically ancient phenotype (over 100 million years old), as is extreme sexual size dimorphism, though their magnitudes vary by lineage,” they wrote. “Despite the sometimes conflicting trends seen within Nephilidae, the clade stands as the most extreme example of female-biased SSD among terrestrial animals, as far as we know.”
The Jason Bond lab and the Chris Hamilton lab, Department of Entomology, Plant Pathology and Nematology at the University of Idaho, Moscow, provided the anchored hybrid enrichment data and phylogenomic analysis.
Co-authors of the paper, in addition to Bond and Hamilton, are
- Matjaž Kuntner of the National Institute of Biology, Ljubljana, Slovenia; the National Museum of Natural History, Smithsonian Institution, Washington D.C.; and Hubei University, China;
- Ren-Chung Cheng, Biological Institute ZRC SAZU, Ljubljana, Slovenia, and National Chung Hsing University, Taiwan;
- Matjaž Gregorič, Nik Lupše and Tjaša Lokovšek, all with the Biological Institute ZRC SAZU, Ljubljana,Slovenia (Lupse is also affiliated with the Charles University, Prague, Czech Republic);
- Emily Moriatry Lemmon and Alan Lemmon, Florida State University, Tallahassee;
- Ingi Agnarsson of the National Museum of Natural History, Smithsonian Institution; and University of Vermont, Burlington; and
- Jonathan Coddington, National Museum of Natural History, Smithsonian Institution.
The research drew funds from Slovenian Research Agency grants, from the U.S. State Department through a Fulbright visiting scholar; ZRZ Director's Fund, National Science Foundation, Doctoral Dissertation Improvement Grant and funds from Auburn University, Alabama. Bond joined the UC Davis faculty in July of 2018 from Auburn University after a seven-year academic career there, where he served as professor of biology and chaired the Department of Biological Sciences. He also curated the arachnids and myriapods (centipedes, millipedes, and related animals) at the Auburn University Museum of Natural History.