7774

• UCREFRP Catalog Number: 7774
• Author: Desert Fishes Council, H., Dean A., ed.)‎.
• Title: Proceedings of the Desert Fishes Council Volume XXIV, 1992 Annual Symposium, 18 to 21 November, Mesa, Arizona.
• USFW Year: 1992.
• USFW - Doc Type: November 18-21.
• Copyright Material: NO

ABSTRACTS OF PRESENTATIONS IN ORDER PRESENTED
1 citELLE, A. A.'; EC1[ MLLE, A. F. (Department of Zoology, Oklahoma state, University, Stillwater, OK)
An allozyme perspective on mitochondrial DNA variation and evolution of the Death Valley
puplishes / Una perspectiva aloenzimica de la variacion de ADN mitocondrial y evoluci6n
de los cachorritos del Valle de la Muerte
KEYWORDS: phylogenetics; allozymes; protein electrophoresis; mitochondrial DNA; Death Valley; Cyprinodontidae;
Cyprinodon
ABSTRACT
We used allozymes encoded by 32 gene loci in 12 species of Cyprinodon (Cyprinodontidae) to examine, the
evolution of the Cyprinodon nevadensis complex, a group of four species (7 extant subspp.) in the Death Valley System
of California and Nevada. The most parsimonious phylogenetic trees supported monophyly of the C. nevadensis complex
(Cyprinodon diabolis, Cyprinodon nevadensis, and Cyprinodon salinus from Ash Meadows-Death Valley, and Cyprinodon
radiosus from Owens Valley). However, a hypothesis involving a diphyletic origin of the complex was nearly as
parsimonious. The geographic distribution of alleles, together with results from an earlier study of mtDNA variation,
suggest that introgressive hybridization has occurred between two divergent pupfishes that gained access to the Death
Valley System. We suggest that secondary contact and introgressive hybridization among western pupfishes may have
been more common in wetter times of the past than is generally appreciated. Such an event would explain conflicting
phylogenetic statements from allozymes and mtDNA, as well as a variety of additional observations on variation in the
western pupfishes.
RESUMEN
Usamos aloenzimas configuradas para 32 genes localizadas en 12 especies de Cyprinodon (Cyprinodontidae) para
examinar la evoluci6n del complejo Cyprinodon nevadensis, un grupo de cuatro especies (7 subespecies existentes) en
el Sistema del Valle de la Muerte de California y Nevada. Los arboles filogen6ticos mas parsimoniosos apoyaron la
monofilia del complejo Cyprinodon nevadensis (Cyprinodon diabolis, Cyprinodon nevadensis, y Cyprinodon salinus de
Ash Meadows-Valle de la Muerte y Cyprinodon radiosus del Valle Owens). Sin embargo, una hip6tesis que involucra
un origen difiletico del complejo fue casi como parsimoniosa. La distribucion geografica de los alelos, junto con el
resultado de un estudio anterior de una variacion de ADN mt, sugiere que ha ocurrido una hibridizacidn introgresiva
entre dos cachorritos divergentes que entraron al Sistema del Valle de la Muerte. Sugerimos que el contacto secundario.
Sugerimos que el contacto secundario de hibridizacidn introgresiva entre cachorritos del oeste pudo haber sido mas comdn
en tiempos mas humedos en el pasado que to generalmente apreciado. Tal evento explicaria declaraciones filogeneticas
conflictivas de aloenzimas y ADN mt, asf conto una variedad de observaciones adicionales sobre variacion de Jos
cachorritos del oeste.
MABEY, L. W.'; SHIOZAWA, D. K. (LWM and DKS - Department of Zoology, Brigham Young University, Provo, LM
The planktonic and benthic microcrustacean communities in the Green River ecosystem
near Ouray, Utah / Comunidades de microcustraceos bent6nicos y planct6nicos en el
ecosistema de Green River, cerca de Ouray, Utah
KEYWORDS: Green River; zooplankton; microcrustaceans; benthos
ABSTRACT
The fry of the Colorado squawfish are known to utilize backwater habitats on the Green River and much of their
diet consists of microcrustaceans. Given the historic association of the Green River with floodplain habitats and other
quiet waters, the native fishes may have relied heavily on food production in these areas. Our objective in this study was
to assess the density and habitat associations of microcrustaceans in both the plankton and benthos of river, backwater,
and floodplain habitats. We selected representative sites for each of these habitat types and collected 50 benthic cores
and five vertical plankton tows per site.
To date 25 species of microcrustaceans have been collected and identified. Seven species were collected in the river
site plankton, while only 3 species occurred in the river benthos. In the backwater site 11 species were collected in the
plankton while 2 species occurred in the benthos. In the wetland floodplain habitat the number of species changed over
time, but in general the highest number of species occurred here, up to 18 in the plankton and 12 in the benthos. Most
species in these three habitats are both planktonic and benthic in habit. Some are more likely to be found in the benthos
or plankton than others, but it is apparent that many of the microcrustaceans are able to exist in either life style. Only
a few species appeared to be obligate members of the plankton or benthos. Densities are high. In one floodplain wetland,
for example, we estimated 205,922 microcrustaceans per cubic meter in the plankton and 261,228 per square meter of
benthos.
RESUMEN
Las larvas de Charal del Colorado (Ptychocheilus Lucius) son conocidas a utilizar los habitats lenticos o de remansos
en el sistema de Green River, ya que gran parte de su dieta se compone de microcrustaceos. Dada la asociaci6n hist6rica
del Green River con los habitats de planicie de inundaci6n y de otros de aguas 16nticas, los peces nativos pudieron haber
22