Andrew Johnston's presentation on Trogloderus (Coleoptera: Tenebrionidae) systematics and speciation in Southwestern United States sand dune habitat, given at the 2014 Annual Meeting of the Entomological Society of America in Portland, OR. http://www.entsoc.org/entomology2014
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Johnston ESA 2014 Trogloderus Sand Dune Speciation
1. Sand Dune Speciation:
Exploring the Evolutionary History of
Trogloderus LeConte
(Coleoptera: Tenebrionidae)
M. Andrew Johnston
2. Trogloderus LeConte 1879
• Erected as a monotypic genus
– 1 specimen from SW Idaho
• Flightless
• Psammophilic
Trogloderus costatus LeConte
– Eolian sand formations
• Western U.S. distribution
Dumont Dunes, CA
Olancha Dunes, CA
3. Trogloderus LeConte 1879
Tribe Amphidorini LeConte 1862
• North American distribution
• 6 genera, ~ 250 species
• Most in Eleodes Eschscholtz
Eleodes armatus LeConte
4. Taxonomic History
Revised by La Rivers, 1946
Trogloderus
costatus
costatus LeConte tuberculatus Blaisdell nevadus La Rivers vandykei La Rivers
ssp. ssp. ssp. ssp.
syn. pappi Kulzer syn. mayhewi Papp
– 4 species subspecies
– 2 more described later
5. Taxonomic History
Revised by La Rivers, 1946
• Invoked orthogenetic evolution
• Hypothesized Trogloderus to be ancient
6. Research Questions
• Does the current taxonomy capture actual
diversity?
• When and where did Trogloderus originate?
• What are the patterns and processes of
diversification across sand dunes?
7. Research Methods
• Morphological analysis
– 1,860 Trogloderus specimens
– Evaluated morphotypes and their distributions
• Molecular analysis
– Phylogenetic reconstruction of Amphidorini
• 77 taxa, 7 gene fragments
– 3 nuclear, 4 mitochondrial
• Aligned in MUSCLE
• Partitioned by PartitionFinder
• Analyzed by RAxML, MrBayes and BEAST
14. Trogloderus Distribution
T. “warneri” sp nov
Great Basin Colorado Plateau
Costae tuberculate
Rugose intervals
Costae and
intervals smooth
Transitional population found along
Northern bank of Lake Powell
15. Trogloderus Distribution
T. “warneri” sp nov
• Gene flow inhibited by
geographic barriers
– Wasatch Mountains
– Colorado River
16. Trogloderus Distribution
Eleodes_giganteus
Eleodes_longicollis
Eleodes_scabriculus
Eleodes_snowii
Eleodes_clavicornis
Eleodes_tenebrosus
Eleodes_barbatus
Lariversius_tibialis_WashoeCo
Lariversius_tibialis
Lariversius_BigDune
Trogloderus_Chilchinbito
100
Trogloderus_Hanksville
Trogloderus_VermCliffs
Trogloderus_CoralPink
Trogloderus_MonoTuber
100
Trogloderus_BeaverDam
Trogloderus_29palms
Trogloderus_Olancha
Trogloderus_PyramidLake
Trogloderus_ElMirage
Trogloderus_DumontDunes
Trogloderus_CrescentDunes
Trogloderus_MonoRetic
Eleodes_spinipes_ventricosus
25
74
100
13
74
77
100
93
42
100
34
91
88
21
80
27
100
100
94
84
Overlapping ranges,
4% sequence divergence
Different male genitalia
T. nevadus nevadus La
Rivers
T. vandykei La Rivers
T. nevadus “aalbui” sp nov
17. Trogloderus Distribution
T. nevadus nevadus La
Rivers
T. vandykei La Rivers
T. nevadus “aalbui” sp nov
Great Basin dune formation
• Late pleistocene 1-3 ma
• Sand derived from dried
pluvial lakes
Owens Valley
• Sand from Owens river
• 10-35 ka
Mojave Desert sand dunes
• Sand from Mojave river
• 10-35 ka
19. Results
• Does current taxonomy capture known
diversity?
– 5 species, 1 currently undescribed
– 2 undescribed subspecies
20. Results
• Does current taxonomy capture known
diversity?
• When and where did Trogloderus originate?
– Likely a young lineage, perhaps with roots in
Pleistocene
– Area of origin unclear, perhaps in the Great Basin
21. Results
• Does current taxonomy capture known
diversity?
• When and where did Trogloderus originate?
• What are the patterns and processes of
diversification?
– Following recent sand formations, 10,000-35,000
years ago
– Mountains and rivers that stop sand, stop gene
flow
22. Future Directions
• Finalize taxonomic revision of the genus
• Increase taxon and geographic sampling for
phylogenetic analyses
• Develop calibrated dating analyses
• Compare Trogloderus to other dune specialist
groups
23. Acknowledgements
Funding
NSF ARTS award DEB-1258154
Specimens and Expertise
Bill Warner Phoenix, AZ
Rolf Aalbu CASC
Warren Steiner USNM
Lee Herman AMNH
Kojun Kanda OSU
Research Group
Nico Franz
Aaron Smith
Sangmi Lee Sal Anzaldo
Guanyang Zhang Chris Henny
Andrew Jansen Omron Blauo
Rebecca Livingston
Photo Credits
Kojun Kanda, Bugguide.net
Aaron Smith, tenebrioniDBase.org
ETOPO1, NOAA