Thomas H. Fritts

PHYLOGEOGRAPHY AND HISTORY OF GIANT GALAPAGOS TORTOISES

Abstract.— We examined the phylogeography and history of giant Galàpagos tortoise populations based on mito‐chondrial DNA sequence data from 161 individuals from 21 sampling sites representing the 11 currently recognized extant taxa. Molecular clock and geological considerations indicate a founding of the monophyletic Galàpagos lineage around 2–3 million years ago, which would allow for all the diversification to have occurred on extant islands. Founding events generally occurred from geologically older to younger islands with some islands colonized more than once. Six of the 11 named taxa can be associated with monophyletic maternal lineages. One, Geochelone porteri on Santa Cruz Island, consists of two distinct populations connected by the deepest node in the archipelago‐wide phylogeny, whereas tortoises in northwest Santa Cruz are closely related to those on adjacent Pinzón Island. Volcan Wolf, the northernmost volcano of Isabela Island, consists of both a unique set of maternal lineages and recent migrants from other islands, indicating multiple colonizations possibly due to human transport or multiple colonization and partial elimination through competition. These genetic findings are consistent with the mixed morphology of tortoises on this volcano. No clear genetic differentiation between two taxa on the two southernmost volcanoes of Isabela was evident. Extinction of crucial populations by human activities confounds whether domed versus saddleback carapaces of different populations are mono‐ or polyphyletic. Our findings revealed a complex phylogeography and history for this tortoise radiation within an insular environment and have implications for efforts to conserve these endangered biological treasures.

Genetic analysis of a successful repatriation programme: giant Galápagos tortoises

As natural populations of endangered species dwindle to precarious levels, remaining members are sometimes brought into captivity, allowed to breed and their offspring returned to the natural habitat. One goal of such repatriation programmes is to retain as much of the genetic variation of the species as possible. A taxon of giant Galápagos tortoises on the island of Española has been the subject of a captive breeding–repatriation programme for 33 years. Core breeders, consisting of 12 females and three males, have produced more than 1200 offspring that have been released on Española where in situ reproduction has recently been observed. Using microsatellite DNA markers, we have determined the maternity and paternity of 132 repatriated offspring. Contributions of the breeders are highly skewed. This has led to a further loss of genetic variation that is detrimental to the long–term survival of the population. Modifications to the breeding programme could alleviate this problem.

Lonesome George is not alone among Galápagos tortoises

Document S1. Supplemental Experimental Procedures and Results, One Table, One Figure and Supplemental ReferencesxDownload (.21 MB ) Document S1. Supplemental Experimental Procedures and Results, One Table, One Figure and Supplemental References

The origin of captive Galápagos tortoises based on DNA analysis: implications for the management of natural populations

Giant tortoises once thrived throughout the Galapagos archipelago, but today three island populations are extinct, only one individual survives from the island of Pinta, and several populations are critically endangered. We established the geographic origin of 59 captive tortoises housed at the Charles Darwin Research Station in the Galapagos Islands in an effort to find a mate for the sole survivor from Pinta (‘Lonesome George’) and to augment the number of breeders in other imperilled populations. By comparison with an extensive database of mtDNA control region (CR) haplotypes and nine microsatellites, we determined the geographic and evolutionary origin of the captive individuals. All individuals had CR haplotypes and multilocus microsatellite genotypes identical to or closely related to known haplotypes from natural populations. No obvious mate was found for Lonesome George, although we found several captive individuals carrying an evolutionarily close but geographically distinct mtDNA haplotype. Tortoises with mtDNA haplotypes closely related to another at-risk population (San Cristobal) were also identified. These individuals could be considered as candidates for augmentation of natural populations or captive-breeding programmes and exemplify how molecular techniques can provide insights for the development of endangered species management plans.

The Distribution and Abundance of Marine Turtles in the Gulf of Mexico and Nearby Atlantic Waters

Aerial surveys of marine waters up to 222 km from shore in the Gulf of Mexico and nearby Atlantic Ocean suggest that marine turtles are largely distributed in waters less than 100 m in depth. The loggerhead turtle (Caretta caretta) was observed nearly 50 times as often in waters off eastern and western Florida as in the western Gulf of Mexico. Loggerheads were present year- round but the frequency of sightings in the winter months was lower than at other seasons. Green turtles (Chelonia mydas) were infrequently observed but were most conspicuous in waters off eastern Florida. Kemps ridleys (Lepidochelys kempi) were most frequently sighted off southwest- ern Florida and rarely observed in the western Gulf of Mexico. Leatherback turtles (Dermochelys coriacea) were more conspicuous on the continental shelf than in adjacent deeper waters. A con- centration of leatherback and loggerhead turtles occurred west of the Gulf Stream Current in August 1980, near Brevard County, Florida. Studies of marine turtles have fo-

A New Teiid Lizard Genus from Western Ecuador

The Santo Domingo de los Colorados region of Pichincha, Ecuador, is one visited by nearly every tourist to the country because of the presence of the famous Colorado Indians. Nevertheless the herpetofauna of this area is very poorly known. Fritts and Smith (1969) described a new colubrid snake from the Rio Baba, 24 km. S Santo Domingo de los Colorados. The present report concerns a new genus and species of teiid lizard from the same area, here named

The significance of diurnal terrestrial emergence of green turtles (Chelonia mydas) in the galápagos Archipelago

The diurnal, nonreproductive emergence of green turtles Chelonia mydas in Galapagos apparently occurs throughout the year on several islands. Turtles on beaches have cloacal temperatures that exceed temperatures of adjacent coastal waters. Basking turtles are predominately females. We hypothesize that females bask to accelerate digestion and fat build-up, necessary antecedents to egg production in reproductive periods. Basking turtles show a trend to clump among available beaches. Such behavior may be a response to microclimatic differences between beaches, although such differences were not apparent to us. The occurrence of thermoregulatory behavior in marine turtles in Galapagos may be a response to the cool waters of the Humboldt Current. DIURNAL, NON-NESTING EMERGENCES of Chelonia mydas on beaches have been reported from several areas of the Pacific Ocean: Hawaiian and Leeward Islands (Kenyon and Rice 1959; Amerson 1971; Balazs and Ross 1974; Balazs 1976, 1980), Australia (Bustard 1973a, b, and 1979), Revillagigedos and Socorro Islands off western Mexico (Slevin 1931, Slevin in Fritts 1981), and the Galapagos Islands (Rogers 1824; Dampier 1906; Slevin 1931, 1935; Parsons 1962; Carr 1967; Pritchard 1971a, b; Slevin in Fritts 1981). Parsons (1962) erroneously quoted Woodes Rogers (1824) as recording the behavior off the coast of western Mexico. Rogers remarks actually referred to Galapagos (Fritts 1981). Balazs and Ross (1974) and Balazs (1976) referred to such emergences as land basking, and proposed that a thermal advantage would be incurred by the basking turtles, but provided no data on the temperatures of turtles exhibiting this behavior. Balazs also argued that emerged turtles would be safe from shark attack, and hence emergence could be a predator-avoidance strategy. Terrestrial emergence is a common thermoregulatory behavior in aquatic turtles (Hutchison 1979). Of the turtles Bustard (1973a, 1979) observed hauled out on beaches on islands off northern Australia, nearly all were females. He hypothesized that females used such forays to avoid frenzied and continued copulatory attempts of males. Joseph Slevin (in Fritts 1981, Fritts and Fritts 1982) found a high percentage of females (94%) on beaches in Galapagos in 1905 and 1906. Slevin assumed (1931, 1935) that these turtles emerged simply to dry off. His data indicate that only about half of the females collected on beaches had enlarged follicles or shelled eggs. The remainder presumably lacked enlarged ova indicating that they were either juveniles or adults in nonreproductive periods (Fritts 1981). Balazs and Ross (1974) and Balazs (1976, 1980) reported that males, females, and juveniles (sex undetermined) bask in Hawaii. However, in each case detailed by Balazs (1980) females were more commonly observed basking than were males. The diurnal, non-nesting emergence of green sea turtles is well documented by the above examples. Unfortunately, few data exist to test the interpretations of Balazs or Bustard. This paper is based on observations and data collected from Chelonia mydas hauled out on beaches or resting in extremely shallow water in the Galapagos Islands. Our objectives were to: determine the size and sex of diurnal, non-nesting emergent turtles; investigate body temperatures of such turtles in relation to ambient air, water, and substrate temperatures; provide data on location, orientation, and general behavior of such turtles; and, examine the existing hypotheses that attempt to explain this phenomenon and to clarify the possible significance of such behavior. MATERIALS AND METHODS Observations of diurnally emergent turtles were made in two ways: incidental sightings were made during various times of the year while the authors were involved in other research in the Galapagos Archipelago; and two systemI Present address: Department of Biology, Texas Christian University, Fort Worth, Texas 76129 U.S.A. BIOTROPICA 15(4): 285-291 1983 285 This content downloaded from 157.55.39.178 on Fri, 05 Aug 2016 06:13:26 UTC All use subject to http://about.jstor.org/terms

Anarbylus switaki Murphy: an Addition to the Herpetofauna of the United States with Comments on Relationships with Coleonyx

Anarbylus switaki, a species previously known only from Baja California Sur, Mex- ico, occurs in eastern San Diego and southwestern Imperial Counties in California. In California, specimens tend to have continuous transverse bars on the body, are lighter in color, and more slender in body form than in southern Baja California. California populations appear to be confined to extremely rocky habitats in desert foothill situations between 200 and 600 m. The species appears to be secretive, and occurs in low densities within rock crevices and subterranean cavities. The morphological gap between Anarbylus and Coleonyx species may not warrant generic recognition. Anarbylus is part of a diverse lizard fauna in southern California and occurs in sympatry with 15 lizard species in a small area of southern California.

A New Anisolepid Anolis (Reptilia: Lacertilia) from Mexico

Anolis anisolepis, new species, type in the University of Illinois Museum of Natural History, is described on the basis of twenty-three specimens from the highlands of western Chiapas. It forms a species-group, with crassulus and haguei, characterized by having strongly keeled ventrals and granular laterals among which are scattered single or groups of enlarged scales. A. crassulus and anis- olepis are sympatric; haguei and crassulus are no doubt subspecifical- ly related as Stuart has long maintained.

A New Genus and Species of Snake from Western Ecuador

Among specimens deposited through the courtesy of Dr. Charles M. Fugler in the University of Illinois Museum of Natural History and collected by George Key in Ecuador, is a snake representing a hitherto unknown genus and species. It bears an extraordinarily close external resemblance to the rare Synophis miops Boulenger (1898), but possesses a remarkable, unique modification of the vertebral column, here assumed to be an anti-twist mechanism supplementing the zygantrum-zygosphene function. The vertebrae exhibit one of the most extreme modifications