A natural history of the vanishing Mexican desert fishes of the genus Characodon
Michael Tobler Whence the diversity? Mechanisms of diversification
Phenotypic diversification Reproductive isolation
Hulsey, 2006 Proc Roy Soc B Hrbek et al., 2003 J Evol Biol Cueva del Azufre: H2S and darkness Non-sulfidic, surface Sulfidic, surface
Non-sulfidic, cave Sulfidic, cave Adaptation and speciation
Sulfidic, cave Sulfidic, surface
Non-sulfidic, cave Non-sulfidic, surface Mechanisms of diversification
Phenotypic diversification Reproductive isolation
Hulsey, 2006 Proc Roy Soc B Hrbek et al., 2003 J Evol Biol Hybridization and phenotypic diversification
C. bifasciatus Introgressed population C. atrorus
Tobler & Carson, 2010 J Evol Biol Hybrids eclipse parental phenotypic variation
1,0 C. atrorus C. bifasciatus Introgressed
0,5
0,0 Residual PCA 2 axis Residual -0,5
-1,0 -2,0 -1,5 -1,0 -0,5 0,0 0,5 1,0 1,5 2,0
Residual PCA axis 1 The big questions
Environment Adaptation Speciation I love Cyprinidontiforms! Acknowledgements
Jim Joel Juan Miguel Langhammer Healy Artigas Azas
• Shane Webb • John Lyons • Nick Bertrand • American Livebearer Association • Photographers I stole pictures from Characodon – a basal lineage within the Goodeidae
Derived characters:
• Simple trophotaenia without lateral branches • Particular ovarian morphology • More dorsal fin rays in males than females • Four branchiostegal rays • 24 chromosomes
Characodon – a basal lineage within the Goodeidae
• Inhabits springs and their outflow • Habitats usually with dense macrophytes • Little known about feeding habits • Often coexists with Cyprinodon meeki, Gila conspersa, Dionda episcopa, and Menidia mezquital
Characodon – a basal lineage within the Goodeidae
• Inhabits springs and their outflow • Habitats usually with dense macrophytes • Little known about feeding habits • Often coexists with Cyprinodon meeki, Gila conspersa, Dionda episcopa, and Menidia mezquital
Characodon – a basal lineage within the Goodeidae
Separation from last common ancestor with other Goodeinae about 10.5 million years ago.
Doadrio & Dominguez (2004) Mol. Phyl. Evol. Characodon – a basal lineage within the Goodeidae
Split caused by uplift of southeastern part of Sierra Madre Occidental
Dominguez et al. (2006) J. Biogeogr. Three described species of Characodon
• C. garmani (Parras Characodon) • Jordan & Evermann, 1898 • Parras drainage • Only known from a single female specimen • Spring habitats are destroyed
Three described species of Characodon
• C. lateralis (Rainbow Characodon) • Gunther, 1866 • Upper Rio Mezquital drainage • Relatively widespread • Convex dorsal profile; males not mostly black & lacking silvery scales; median fins with yellow or red band and a black margin
Three described species of Characodon
• C. audax (Bold Characodon) • Smith & Miller, 1986 • Upper Rio Mezquital drainage • Endemic to El Toboso • Dorsal profile indented at nape; breeding males dark, sides flecked with silvery scales; no yellow or orange in median fins
Three described species of Characodon Variation among Characodon populations Research questions
• What was the historic morphological variation across populations? • How does morphology relate to geography and phylogenetic relationships? • What are the implications for taxonomy and conservation? • What is the current conservation status?
Geometric morphometric analysis Samples used Body shape changes with size and sex
Centroid size (from small to large)
Sex (from male to female) Populations are significantly different in body shape
1,0
2 1 0,5 6 4 5 9 7
0,0
PC 2 PC 1. Los Pinos 3 -0,5 10 2. Guadalupe Aguilera 3. Cerro Gordo 8 4. Aguila 5. El Toboso 6. Rio Mezquital -1,0 7. Rio Sauceda 8. Hot springs 9. Presa Tunal 10.Los Berros
-1,5 -1,0 -0,5 0,0 0,5 1,0 1,5
PC 1 Populations are significantly different in body shape
Aguila (4; 35.3 %)
Rio Mezquital (6; 85.2 %)
Agua de las Mujeres (2; 87.2 %)
Los Pinos (1; 89.8 %)
Rio Sauceda (7; 46.7 %)
Hot springs (8; 62.0 %)
Presa Tunal (9; 75.4 %)
Cerro Gordo (3; 81.1 %)
Los Berros (10; 91.7 %)
El Toboso (5; 95.9 %) Conclusions
• Populations are significantly different from each other in morphology and male nuptial colorations • Hydrographic units explain deep splits in morphological differentiation • Distinctness of the El Toboso population is consistent with the description of C. audax Conclusions
Morphology suggests splits according to hydrographic units:
(1) Separation of El Toboso (C. audax s. s.)
(2) Separation between populations below and above the El Salto waterfall Molecular phylogenetic data
1 Abraham Gonzales f1 1Abraham Gonzales m1 1 El Toboso AQ El Toboso f2 El Toboso m3 Guadalupe Aguilera 38 Guadalupe Aguilera f1 Guadalupe Aguilera m2 Los Pinos f1 Los Pinos m1 27 de noviembre f2 27 de noviembre m2 1 Amado Nervo f2 13 1 Amado Nervo f3 Amado Nervo m2 2 Los Berros f1 2 Los Berros m2 1 1 23 Los Berros AQ 1 unknown f2 3 Los Berros AQ 40 28 unknown f1 3 Amado Nervo m3 7 32 Goodea atripinnis 53 Xenotaenia resolanae 57 Ataeniobius toweri 41 31 Crenichthys baileyi 32 Empetrichthys latos 79 Profundulus labialis Shane Webb, unpublished data Morphological data is inconsistent with phylogeny
Morphology Genetics Below falls
Above falls
El Toboso Taxonomic problems
• What is C. audax? Based on genetic analyses, all populations above the falls should be named C. audax This procedure has implicitly been adopted Required re-analysis and re-description of the species
Taxonomic problems
• What is C. lateralis? Type locality is unknown Taxonomic problems Taxonomic problems
• What is C. lateralis? Type locality is unknown Implicitly type locality is assumed to be Los Berros Requires designation of a neotype
Detailed study of relationship and taxonomic traits is needed! Current status of Characodon populations Current status of Los Pinos
• Absent in 2011 • 300 m of suitable habitat • Last record in 2001 by JMAA Current status of Laguna Seca (Guadalupe Aguilera)
• Present in 2011 • Population apparently stable • Invasive Oreochromis aureus present Current status of Cerro Gordo
• Absent in 2011 • Spring has been try potentially for almost 20 years • Last record in 1982 by RRM Current status of San Vincente de Chupaderos
• Absent in 2011 • No specimens found on repeated visits since 1999 • Invasive Goodea atripinnis and Lepomis macrochirus present • Last record in early 1990s by CS Current status of Presa Peñon del Aguila
• Absent in 2011 • No specimens found on repeated visits since 1993 • Invasive Lepomis macrochirus and Micropterus salmoides present Current status of El Toboso (C. audax)
• Absent in 2011 • Invasive Gambusia senilis present • Last record in 2006 by JMAA Current status of El Tobosito
• Absent in 2011 • No specimens found on repeated visits since 2003 • Invasive Gambusia senilis present • Last record in early 1990s by DI Current status of Ojo Garabato (27 de Noviembre)
• Present in 2011 • Population apparently stable • Invasive Oreochromis aureus, Lepomis machrochirus, and Gambusia senilis present Current status of Los Berros (Ojo de Agua San Juan)
• Present in 2011 • Reduced abundance compared to the past • Invasive Oreochromis aureus and Xiphophorus hellerii present Current status of La Constancia
• Present in 2011 • Apparently stable despite small habitat • Invasive Oreochromis aureus and Xiphophorus hellerii present Current status of Amado Nervo
• Present in 2011 • Only a single juvenile individual found; numbers appeared stable 1993-2010 • Invasive Oreochromis aureus and Xiphophorus hellerii present Summary: Characodon is rapidly disappearing
• Only 4 of formerly 18 populations remain apparently stable • El Toboso and Amado Nervo recently in critical condition 80% reduction in range (other recent estimates ranged from 30-60%; Dominguez-Dominguez et al. 2006, Conserv. Biol.) Conservation threats: Invasive species
• Predation • Competition • Ecosystem effects Conservation threats: Water use
• Surface water diversion • Ground water use Disappearance of habitats
• Pollution • Land use changes Degradation of habitats Conservation strategies
• Population monitoring • Protection and improvement of habitats • Invasive species removal • Establishment of refuge populations in artificial and unoccupied habitats Conservation implications
• Characodon populations need to be managed independently • Keep stocks separate Fish Chum – Chatter for Fish Heads
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http://fishchum.okstate.edu Michi Tobler Oklahoma State University [email protected] http://www.sulfide- life.info/mtobler