Pattern of Differential Divergence Among Five Insular Species of the Aspidoscelis hyperythra Complex (Squamata: Teiidae), Baja California Sur, México
The most recent taxonomic revision of the Aspidoscelis hyperythra complex of teiid lizards from Baja California referred all peninsular populations to A. hyperythra and recognized five insular populations as species based on their diagnosability and allopatric distributions. We used multivariate analyses of seven quantitative morphological characters to determine relative distinctiveness and divergence among these populations and the four geographically closest peninsular populations of A. hyperythra. The two northernmost insular species, Aspidoscelis picta (Isla Monserrate) and Aspidoscelis carmenensis (Isla Carmen) were significantly more divergent than were Aspidoscelis danheimae (Isla San José), Aspidoscelis franciscensis (Isla San Francisco), Aspidoscelis espiritensis (Islas Espiritu Santo and Partida Sur), and peninsular samples of A. hyperythra. Divergence information from mtDNA sequence variation divided the five insular species into the same high-divergence/low-divergence groups. We present new testable hypotheses relating to relative times of colonization and peninsular location of the source population of island colonists. La revisión taxonómica más reciente del complejo Aspidoscelis hyperythra de lagartijas teidas de Baja California considera a todas las poblaciones peninsulares como A. hyperythra y reconoce cinco poblaciones insulares como especies basándose sobre en características diagnósticas y distribuciones alopátricas. Utilizamos análisis multivariado de siete características morfológicas cuantitativas para determinar la diferencia y divergencia relativas entre estas poblaciones y las cuatros poblaciones peninsulares más cercanas geográficamente de A. hyperythra. Las dos especies insulares más septentrionales, Aspidoscelis picta (Isla Monserrate) y Aspidoscelis carmenensis (Isla Carmen) fueron significativamente más divergentes que Aspidoscelis danheimae (Isla San José), Aspidoscelis franciscensis (Isla San Francisco), Aspidoscelis espiritensis (Islas Espíritu Santo y Partida Sur), y muestras peninsulares de A. hyperythra. Información sobre la divergencia de estas especies a partir de variación en las secuencias de ADN mitocondrial dividió las cinco especies insulares en los mismos grupos de alta-divergencia/baja-divergencia. Presentamos nuevas hipótesis comprobables sobre los tiempos relativos de colonización y ubicación peninsular de las poblaciones fuente que colonizaron las islas.Abstract
Resumen
Map with sampling localities for taxa referenced in text. All peninsular localities are sampling sites of A. hyperythra. Insular taxa: Isla Carmen (A. carmenensis); Isla Monserrate (A. picta); Isla San José (A. danheimae); Isla San Francisco (A. franciscensis); Islas Partida Sur and Espiritu Santo (A. espiritensis).
Representatives of insular species (not at same scale): (A) Aspidoscelis carmenensis from Isla Carmen (CAS 100336; male, 60 mm snout–vent length [SVL]). (B) Aspidoscelis picta from Isla Monserrate, the most strikingly divergent color pattern variant in the A. hyperythra complex (LACM 135820; male, 71 mm SVL). (C) Aspidoscelis danheimae from Isla San José (CAS 52733; male 64 mm SVL). (D) Aspidoscelis franciscensis from Isla San Francisco (CAS 52733; male, 64 mm SVL). (E) Aspidoscelis espiritensis from Isla Espiritu Santo (CAS 52779; male 62 mm SVL).
Representative specimens of Aspidoscelis hyperythra from Loreto-Puerto Escondido, the peninsular population most-closely resembled by all of the insular populations: (A) CAS 53650; male, 64 mm snout–vent length (SVL). (B) CAS 53652; female, 55 mm SVL. (C) CAS 53655; male 57 mm SVL. (D) CAS 53656; male 64 mm SVL. Check Table 2 for sample variation in number of stripes.
Representatives of peninsular Aspidoscelis hyperythra (not at same scale) from: (A) La Paz (CAS 46853; male, 65 mm snout–vent length [SVL]). (B) San Pedro (CAS 46885; male, 60 mm SVL). (C) Santiago (LACM 14801; male, 57 mm SVL). Check Table 2 for sample variation in number of stripes.
CV1 and CV2 scores for nine samples and 292 representatives of the Aspidoscelis hyperythra complex. Percentages represent proportion of variation accounted for by CV1 and CV2. Confidence ellipses enclose 95% of sample variation. Solid lines: A. carmenensis and A. picta; dashed lines: A. danheimae, A. franciscensis, and A. espiritensis; dotted lines: peninsular samples of A. hyperythra.
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