Faustino Camarena-Rosales

Mitochondrial haplotype variation in wild trout populations (Teleostei: Salmonidae) from northwestern Mexico

The variation and composition of Mexican wild trout mitochondrial DNA haplotypes throughout northwestern Mexico was determined by means of polymerase chain reaction–restriction fragment polymorphism analysis (PCR–RFLP), of one region of mitochondrial DNA between cytochrome b and the D-loop. This analysis was based on 261 specimens taken in 12 basins and four hatcheries from northwestern Mexico. From 23 haplotypes, 15 wild trout haplotypes were identified and classified in four groups: (1) one restricted to Nelson’s trout (Oncorhynchus mykiss nelsoni), (2) four restricted to Río Mayo and RíoYaqui trout (O. mykiss sspp.), (3) six to Mexican golden trout (O. chrysogaster) with two subgroups, and (4) one exclusive to Río Piaxtla trout. Distributions of native haplotypes broadly overlap the distribution of non-native hatchery rainbow trout reflecting the historical management of introductions of exotic rainbow trout and the artificial transference of these trout among basins.

DISTRIBUTION AND ABUNDANCE OF THE ENDANGERED KILLIFISH FUNDULUS LIMA, AND ITS INTERACTION WITH EXOTIC FISHES IN OASES OF CENTRAL BAJA CALIFORNIA, MEXICO

Abstract The distribution and abundance of the endangered Baja California killifish, Fundulus lima, and its interaction with exotic fishes were studied in oases of the central part of Baja California peninsula, Mexico (Río San Ignacio and Río La Purísima basins), from October 2002 to July 2004. Five fish species were recorded: the native killifish and 4 exotics (Cyprinus carpio, Poecilia reticulata, Xiphophorus hellerii, and Tilapia cf. zillii). Two new populations of the killifish are reported for the Río San Ignacio as well as confirmation of occurrence in the upper Río La Purísima. Density of the killifish in the Río San Ignacio showed a significant inverse correlation with that of the exotic redbelly tilapia (Tilapia cf. zillii). Baja California killifish densities in both rivers decreased significantly after the hurricane-induced flood event of 23 September 2003, but exhibited notable recovery 10 months later. Relative abundance of killifish at the type locality, San Ignacio oasis, decreased significantly during an 8-year period after introduction of tilapia. The status of Baja California killifish should be changed from threatened to endangered to reflect continued reductions in distribution as result of proliferation of nonnative fishes, particularly redbelly tilapia. Management efforts to reduce abundance of exotic fishes are needed to ensure persistence of the endemic Baja California killifish.

Population morphometric variation of the endemic freshwater killifish, Fundulus lima (Teleostei: Fundulidae), and its coastal relative F. parvipinnis from the Baja California Peninsula, Mexico

The population morphometric variation of the endangered freshwater killifish (Fundulus lima) was evaluated and compared with that of its euryhaline coastal relatives (F. parvipinnis parvipinnis and F. p. brevis) on the basis of 384 specimens from the Baja California peninsula, Mexico. Forty five standardized body distances were compared by means of discriminant function analysis (DFA). Sixteen body distances were significant to distinguish two groups of populations for F. lima: a first group represented by the Bebelamas and San Javier basins, and second group composed by the basins of San Ignacio, La Purísima, San Luis, San Pedro and Las Pocitas. When all freshwater and coastal populations were compared, the southernmost population of F. lima (Las Pocitas) showed a higher morphometric similarity with the southern coastal subspecies (F. p. brevis), while another southern population (San Pedro) had an intermediate position between the freshwater and coastal forms. This study suggests the presence of five evolutionary units (three freshwater and two coastal) for the genus Fundulus in the Baja California peninsula.

Biometric and Allozymic Characterization of Three Coastal and Inland Killifish Populations (Pisces: Fundulidae) from the Peninsula of Baja California, Mexico

Type localities and/or central populations of coastal and inland killifishes along the peninsula of Baja California were sampled to survey the biometric and allozymic relationships among them. The standard stepwise discriminatory function analysis of biometric characters classified organisms into three well distinctive groups (p < 0.001 ). The number of scales in the lateral series successfully split the species, while the caudal length/standard length ratio did so between subspecies. Two diagnostic loci (PROT-2 * and AAT-2 * ) segregated private alleles in each taxon. Fundulus lima showed lower genetic variability levels than F. parvipinnis spp., in both polymorphism (18.8% in F. lima vs. 25.0% in F. parvipinnis spp.) and expected heterozygosity (0.060 in F. lima vs 0.099 in F. p. brevis and 0.089 in F. p. parvipinnis). The reduced genetic variability in the threatened species F. lima may be related to its evolutionary history. Neis genetic distance between F. lima and F. p. parvipinnis was 0.247, while 0.075 between F. parvipinnis spp.

Complete mitochondrial genome of Ictalurus pricei (Teleostei: Ictaluridae) and evidence of a cryptic Ictalurus species in Northwest Mexico.

Abstract The nominal Yaqui catfish, Ictalurus pricei, is a species of Ictaluridae (Siluriformes) often recorded from Northwest Mexico. Southern distribution members of the I. pricei complex in Northwest Mexico include at least one undescribed species that differs from Yaqui catfish in morphological features, herein called “Sinaloa Catfish”. Sequencing of four geographical mitogenome haplotypes of Yaqui catfish and Sinaloa catfish showed geographical haplotypes of I. pricei within a clade of specific identity, close to Sinaloa catfish haplotypes. Our molecular phylogeny represents a working hypothesis supporting information on the evolutionary relationships of the Ictalurus species from Western Mexico and Western USA.

Assessing population-level morphometric variation of the Mountain Mullet Agonostomus monticola (Teleostei: Mugilidae) across its Middle American distribution

Population-level morphometric variation of the Mountain Mullet (Agonostomus monticola) was assessed in 419 adult specimens from 25 sample sites (river basins) across its Middle American distribution (Pacific and Atlantic-Caribbean drainages). This analysis was based on 36 standardized linear measurements and 19 landmarks on geometric morphometrics approach. Discriminant function analysis (DFA) revealed 19 linear morphological characters with significant variation among groups. Geometrically, the most notable changes were associated to the curvature of the frontal region of the head, the anterior and posterior insertion of the first dorsal and anal fins. The resulting grouping based on the DFA and geometric morphometrics techniques (Pacific-A, Pacific-B and NE México-Caribbean) were similar to those previously recovered by genetic techniques, where the Pacific-B (Ayuquila river basin) was the most different group. Our results provide morphological evidence for considering Agonostomus monticola as a complex of evolutionary entities, represented by two forms in the Pacific Ocean and another in the Atlantic Ocean.

Entire mitochondrion genome sequence of the Desert Pupfish, Cyprinodon macularius Baird & Girard, 1853

Abstract The complete mitochondrial genome sequence of the Desert Pupfish, Cyprinodon macularius (Gene accession number KM985373) has a length of 16,940 bp, and the arrangement consisted of 13 protein-coding genes, 2 ribosomal RNA (rRNA) genes and 22 transfer RNA, which are similar to other known mitogenomes for the family Cyprinodontidae.