Article

Phylogenetic Relationships within the Eared Seals (Otariidae: Carnivora): Implications for the Historical Biogeography of the Family

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  • Wildlife Conservation Society (WCS) Canada
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Abstract

Phylogenetic relationships within the family Otariidae were investigated using two regions of the mitochondrial genome. A 360-bp region of the cytochrome b gene was employed for the primary phylogenetic analysis, while a 356-bp segment of the control region was used to enhance resolution of the terminal nodes. Traditional classification of the family into the subfamilies Arctocephalinae (fur seals) and Otariinae (sea lions) is not supported, with the fur seal Callorhinus ursinus having a basal relationship relative to the rest of the family. This is consistent with the fossil record which suggests that this genus diverged from the line leading to the remaining fur seals and sea lions about 6 million years ago (mya). There is also little evidence to support or refute the monophyly of sea lions. Four sea lion clades and five fur seal clades were observed, but relationships among these clades are unclear. Similar genetic divergences between the sea lion clades (D(a) = 0.054-0.078), as well as between the major Arctocephalus fur seal clades (D(a) = 0.040-0.069) suggest that these groups underwent periods of rapid radiation at about the time they diverged from each other. Rapid radiations of this type make the resolution of relationships between the resulting species difficult and indicate the requirement for additional molecular data from both nuclear and mitochondrial genes. The phylogenetic relationships within the family and the genetic distances among some taxa highlight inconsistencies in the current taxonomic classification of the family.

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... Early suggestions that this subfamilial classification might be incorrect (e.g. [29]) have received increasing support from recent molecular analyses [12,14,15,[30][31][32]. Taken together with a number of reports of both interspecific and intergeneric hybrids within Otariidae (e.g. ...
... Several recent genetic studies [11,12,14,15,24,26,32] have advanced our knowledge of relationships within Pinnipedia considerably. Unfortunately, many of these (the exceptions being [14,24,26]) did not include divergencedate estimates as required for some types of macroevolutionary studies and phylogenetic comparative analyses. ...
... General structure of the supertree Our preferred hypothesis of pinniped evolution is that derived from the molecular supertree with all genes analyzed individually ( Fig. 1; see Methods). It agrees broadly with other recent studies (e.g., [10][11][12][13][14][15]23,24,26,32]). In particular, the monophyly of each of Pinnipedia, Otarioidea, Phocidae, Otariidae, and the two phocid subfamilies was supported. ...
... Morphological phylogenies (Fig. 1) recognize two to three major clades, a monophyletic Otariinae (sea lions; Berta & Deméré, 1986; Barnes, Ray & Koretsky, 2006) and a monophyletic Arctocephalus (southern fur seals; Berta & Deméré, 1986), with the northern fur seal Callorhinus as either the sister taxon to Arctocephalus, forming a monophyletic Arctocephalinae (Berta & Deméré, 1986), or as the earliest diverging lineage of crown Otariidae (). By contrast, genotype-based phylogenies of Otariidae recover Otariinae, Arctocephalinae, and Arctocephalus as paraphyletic (Wynen et al., 2001; Árnason et al., 2006; *Corresponding author. E-mail: mchurch3@uwyo.edu ...
... Southern Hemisphere otariids are found as the monophyletic sister group to this clade. Within the Southern Hemisphere, Otaria is either found to be embedded within Arctocephalus (Wynen et al., 2001; Árnason et al., 2006), the earliest diverging lineage of southern otariid (Higdon et al., 2007), or unresolved within the southern clade (Yonezawa et al., 2009). Phocarctos and Neophoca are recovered as embedded within the Arctocephalus clade (Yonezawa et al., 2009), although most molecular phylogenies are unable to resolve the phylogenetic position of Neophoca within Otariidae (Wynen et al., 2001; Árnason et al., 2006; Higdon et al., 2007). ...
... Within the Southern Hemisphere, Otaria is either found to be embedded within Arctocephalus (Wynen et al., 2001; Árnason et al., 2006), the earliest diverging lineage of southern otariid (Higdon et al., 2007), or unresolved within the southern clade (Yonezawa et al., 2009). Phocarctos and Neophoca are recovered as embedded within the Arctocephalus clade (Yonezawa et al., 2009), although most molecular phylogenies are unable to resolve the phylogenetic position of Neophoca within Otariidae (Wynen et al., 2001; Árnason et al., 2006; Higdon et al., 2007). Disagreement on the phylogeny of Otariidae has led to markedly different interpretations of biogeography in the group. ...
Article
Fur seals and sea lions (Carnivora: Otariidae) evolved in the North Pacific and later dispersed throughout the Southern Hemisphere. However, the timing and number of dispersals into the Southern Hemisphere still remain poorly understood. To determine the biogeographical patterns of dispersal within fur seals and sea lions, we conducted cladistic analyses using combined evidence incorporating morphological and molecular data. The phylogeny produced in this study was then incorporated into Bayesian biogeographical analyses to reconstruct ancestral points of origin and dispersal patterns for otariid clades. Combined evidence analyses supported Callorhinus as the earliest diverging extant otariid, and a strongly supported northern sea lion clade (Zalophus, Eumetopias, and Proterozetes) as the sister group to a southern clade comprising the remainder of Otariidae. Fossil data constrained the timing and location of this dispersal as occurring between 6 and 7 Mya during a period of unusually cool sea surface temperatures and high productivity in the eastern equatorial Pacific, far older than suggested by prior studies. Our study indicates that the distribution of fur seals and sea lions is tightly linked to sea surface temperature and productivity, and suggests that otariids may be vulnerable to future anthropogenic climate change. © 2014 The Linnean Society of London
... five additional sequences from Ile Amsterdam and Iles Crozet (Wynen et al. 2001) , that are available on Genbank, were subsequently added bringing the sample size of the A. tropicalis dataset to 121 individuals. Similarly, for A. gazella, a Marion-only dataset (N=78) was compiled with sequences generated in this study alone (N=58) and 20 generated previously (Wynen et al. 2000). ...
... dataset, comprised the 78 Marion Island sequences, 20 Bouvetøya sequences that were included in theWynen et al. (2000) study and a further 5 (AF384376-80) from Bouvetøya(Wynen et al. 2001), bringing the sample size of the latter dataset to 103 individuals. Minimum evolution (ME) trees were constructed using each of the Marion Island-only and combined all-island datasets detailed previously, in MEGA version 3.1(Kumar et al. 2001). ...
... Lineage I comprised 23 haplotypes recovered from 94 individuals (with 90 % bootstrap support) whilst lineage II had 2 haplotypes from 9 individuals (supported by 99 % of the bootstrap replicates). Marion Island and Bouvetøya shared 5 haplotypes (Table 2.3); Combined A. gazella and A. tropicalis data set The mtDNA sequences of 116 individuals of A. tropicalis (96 from Marion and 20 from Gough) and 98 individuals of A. gazella (78 from Marion and 20 from Bouvetøya) together with sequences from 5 individuals each of A. tropicalis and A. gazella downloaded from the Genbank(Wynen et al. 2001), were used to compile a haplotype dataset. This haplotype dataset comprising 51 haplotypes (25 were from A. gazella and 26 from A. tropicalis) was used for phylogenetic analysis of the combined dataset(Fig 2.6). ...
... The two recognized subspecies of Arctocephalus pusillus, A. p. pusillus and A. p. doriferus are almost identical in anatomy, behaviour and genetics showing very little divergence (Repenning et al. 1971, Warneke and Shaughnessy 1985, Wynen et al. 2001). Repenning et al. (1971) accorded the Australian Fur Seal (A. p. doriferus) subspecific status based on one cranial character and separate geographic ranges. ...
... Repenning et al. (1971) accorded the Australian Fur Seal (A. p. doriferus) subspecific status based on one cranial character and separate geographic ranges. Very low genetic divergence indicates that they split relatively recently, with the Australian subspecies being the more recently established (Lento et al. 1997, Wynen et al. 2001), possibly derived as a consequence of late Pleistocene/Holocene (~12,000 years before present) migration events from southern Africa to southern Australia via west-wind drift across the Indian Ocean (Wynen et al. 2001, Deméré et al. 2003). Australian Fur Seals have previously been named A. forsteri, A. doriferus and A. tasmanicus (Repenning et al. 1971). ...
... Repenning et al. (1971) accorded the Australian Fur Seal (A. p. doriferus) subspecific status based on one cranial character and separate geographic ranges. Very low genetic divergence indicates that they split relatively recently, with the Australian subspecies being the more recently established (Lento et al. 1997, Wynen et al. 2001), possibly derived as a consequence of late Pleistocene/Holocene (~12,000 years before present) migration events from southern Africa to southern Australia via west-wind drift across the Indian Ocean (Wynen et al. 2001, Deméré et al. 2003). Australian Fur Seals have previously been named A. forsteri, A. doriferus and A. tasmanicus (Repenning et al. 1971). ...
... Phylogenetic relationships among otariid species are still under extensive debate. Classic studies supported by morphological data suggested that fur seals and sea lions were monophyletic groups within the otariids (King 1983, Wyss 1988, Berta and Wyss 1994, whereas more recent studies using mitochondrial gene sequences suggest the groups are polyphyletic (Wynen et al. 2001, Higdon et al. 2007, Yonezawa et al. 2009). Despite the ambiguity, it has been established that the northern fur seal (Wynen et al. 2001, Berta et al. 2006, Higdon et al. 2007, Yonezawa et al. 2009). ...
... Classic studies supported by morphological data suggested that fur seals and sea lions were monophyletic groups within the otariids (King 1983, Wyss 1988, Berta and Wyss 1994, whereas more recent studies using mitochondrial gene sequences suggest the groups are polyphyletic (Wynen et al. 2001, Higdon et al. 2007, Yonezawa et al. 2009). Despite the ambiguity, it has been established that the northern fur seal (Wynen et al. 2001, Berta et al. 2006, Higdon et al. 2007, Yonezawa et al. 2009). After divergence from the common ancestor with the northern fur seal, there have likely been multiple transitions to the "sea lion" condition, as sea lion species appear on multiple branches within the otariid tree (Wynen et al. 2001, Higdon et al. 2007, Yonezawa et al. 2009, Liwanag et al. 2012a. ...
... Despite the ambiguity, it has been established that the northern fur seal (Wynen et al. 2001, Berta et al. 2006, Higdon et al. 2007, Yonezawa et al. 2009). After divergence from the common ancestor with the northern fur seal, there have likely been multiple transitions to the "sea lion" condition, as sea lion species appear on multiple branches within the otariid tree (Wynen et al. 2001, Higdon et al. 2007, Yonezawa et al. 2009, Liwanag et al. 2012a. Differences in pelage morphology therefore suggest that a dense, waterproof fur layer is a trait that sea lions have secondarily lost through multiple convergent events (Liwanag et al. 2012a). ...
... Differentiation of three presently recognised Uncinaria species parasitising pinnipeds based on morphological diagnoses is generally supported by the geographical separation of their specific hosts (King, 1983;Wynen et al., 2001). The only exception is the co-occurrence of the California sea lion and the northern fur seal on San Miguel Island (California, USA), where the hosts of U. lyonsi n. sp. and U. lucasi breed and share rookeries . ...
... Close phylogenetic relationships between U. lyonsi n. sp. and U. lucasi revealed by molecular studies on Uncinaria spp. (see Nadler et al., 2013) do not coincide with the relationships of their type-hosts on the phylogenetic tree of the Otariidae (Wynen et al., 2001;Yonezawa et al., 2009); C. ursinus and Z. californianus belong to different clades. However, U. lucasi is known to parasitise also the Steller sea lion Eumetopias jubatus Schreber, which belongs to a separate clade of otariids together with the California sea lion. ...
... This fact may support the co-evolutional relationships between Uncinaria spp., at least from the North American clade, and their otariid hosts. According to this presumption, the northern fur seal might have acquired U. lucasi from the Steller sea lion due to the co-existence of these two hosts in the same areas in the North Pacific (King, 1983;Wynen et al., 2001). (Beltsville, MD, USA), for the specimens of Uncinaria kindly loaned for our study. ...
Article
A new species of hookworm, Uncinaria lyonsi n. sp., is described based on morphological studies of the nematodes collected by Dr. E. T. Lyons from the California sea lion Zalophus californianus (Lesson) on San Miguel Island, California, USA. The new species is morphologically similar to three other species of the genus Uncinaria Frölich, 1789 parasitising pinnipeds, U. lucasi Stiles, 1901, U. hamiltoni Baylis, 1933 and U. sanguinis Marcus, Higgins, Šlapeta & Gray, 2014, in the body dimensions, the structure of the buccal capsule, the shape and structure of the male caudal bursa and female genital system. Uncinaria lyonsi n. sp. is differentiated from U. lucasi by having longer spicules and gubernaculum, larger buccal capsule and more slender oesophagus. The new species differs from U. hamiltoni and U. sanguinis in having shorter spicules and narrower buccal capsule. The latter two species also occur in the Southern Hemisphere and are geographically separated from U. lyonsi n. sp. The present study confirms the existence of a host-specific species of Uncinaria in the California sea lion, previously revealed by molecular and biological investigations.
... Yonezawa, Kohno & Hasegawa et al., 2009;Nyakatura & Bininda-Emonds, 2012;Berta & Churchill, 2012), however, have stated that these subdivisions are no longer valid. Rapid radiations of species within Otariidae (Wynen et al., 2001) make the resolution of relationships between species difficult and indicate the requirement for additional data (both genetic and morphological). Consequently, the number of species and their evolutionary relationships remain controversial within this family (e.g. ...
... For instance, the southern fur seals have been traditionally included in the genus Arctocephalus, which has been reported as paraphyletic in recent works (e.g. Wynen et al., 2001;Árnason et al., 2006;Fulton & Strobeck, 2006;Higdon et al., 2007;Yonezawa, Kohno & Hasegawa, 2009). Indeed, in a recent taxonomic review Berta & Churchill (2012) transferred five out of six species formerly included in Arctocephalus to the genus Artophoca, limiting the genus Arctocephalus as monospecific [Arctocephalus pusillus (Schreber, 1775)]. ...
... Indeed, genetic divergences between the major otariid clades suggested the period in which they diverged from each other represents a rapid radiation (i.e. 6.7 Myr, Wynen et al., 2001; A, same slope and intercepts for A. australis, A. gazella, and A. tropicalis; B, different slopes between the growth trajectories; and C, same slope and different intercepts between species. Abbreviations as in Figure 2. Yonezawa et al., 2009). ...
Article
We analysed the cranial ontogeny of male Arctocephalus australis (Zimmermann, 1783) (N = 116), Arctocephalus gazella (Peters, 1875) (N = 69), and Arctocephalus tropicalis (Gray, 1872) (N = 51) to study skull growth and its allometric patterns in the genus. We used 15 metric variables with bivariate and multivariate approaches to detect interspecific similarities and differences between growth trends, which we discussed in the context of phylogeny and life history. We found common trajectories in 20% of variables, detecting that the differences between adults were associated with size. We detected higher growth rates in A. gazella than in A. australis and A. tropicalis, which were associated with shape differences. Amongst the three species, A. tropicalis was morphologically intermediate, showing additional common trends with A. gazella and A. australis, and an intermediate position in the multivariate morphospace. Allometric patterns were also compared with growth trends described for Otaria byronia (Péron, 1816) and Mirounga leonina (Linnaeus, 1758). We detected positive allometry in Arctocephalus for the mastoid width (MW) but negative allometry in O. byronia and M. leonina. This could indicate that males of Arctocephalus exhibited a delayed development of MW. Finally, the presence of common growth trends for the skull length and the postorbital constriction could indicate a conservative pattern within otariids. © 2014 The Linnean Society of London
... Nevertheless, this is the first described pinniped fossil from the early Pleistocene of the Northeast Pacific. Callorhinus is the earliest known extant pinniped taxon represented from the fossil record of the Northeast Pacific, and extant C. ursinus consistently exhibits the basal-most phylogenetic position among extant Otariidae in molecular (Wynen et al., 2001;Yonezawa et al., 2009) and morphological phylogenetic hypotheses (Berta and Deméré, 1986;Berta and Wyss, 1994;Kohno and Yanagisawa, 1997;Deméré and Berta, 2005; but see Brunner, 2004). Whereas (de Muizon, 1978) placed the Mio-Pliocene fur seal Thalassoleon and Callorhinus within the subfamily "Callorhininae," cladistic analyses have placed Thalassoleon as an early diverging otariid (Berta and Deméré, 1986). ...
... Whereas (de Muizon, 1978) placed the Mio-Pliocene fur seal Thalassoleon and Callorhinus within the subfamily "Callorhininae," cladistic analyses have placed Thalassoleon as an early diverging otariid (Berta and Deméré, 1986). Whereas the morphological analysis by Berta and Deméré (1986) supported monophyly of the "Arctocephalinae" (Arctocephalus + Callorhinus), numerous molecular and morphologic phylogenetic hypotheses indicate that the "Arctocephalinae" (and even the genus Arctocephalus) are probably paraphyletic (Wynen et al., 2001;Brunner, 2004;Yonezawa et al., 2009). Other issues surrounding otariid phylogeny concern the "Otariinae" (fossil and extant sea lions; Eumetopias, Neophoca, Otaria, Phocarctos, Proterozetes, and Zalophus), which are also probably paraphyletic (Wynen et al., 2001;Brunner, 2004;Yonezawa et al., 2009). ...
... Whereas the morphological analysis by Berta and Deméré (1986) supported monophyly of the "Arctocephalinae" (Arctocephalus + Callorhinus), numerous molecular and morphologic phylogenetic hypotheses indicate that the "Arctocephalinae" (and even the genus Arctocephalus) are probably paraphyletic (Wynen et al., 2001;Brunner, 2004;Yonezawa et al., 2009). Other issues surrounding otariid phylogeny concern the "Otariinae" (fossil and extant sea lions; Eumetopias, Neophoca, Otaria, Phocarctos, Proterozetes, and Zalophus), which are also probably paraphyletic (Wynen et al., 2001;Brunner, 2004;Yonezawa et al., 2009). Out of convenience, sea lions are referred to herein as the 'otariines,' recognizing the possibility that this is a paraphyletic grade. ...
Article
New fossils representing two species of the fur seal Callorhinus are reported from the uppermost Pliocene to lower Pleistocene Rio Dell Formation of northern California. The finds include latest Pliocene–earliest Pleistocene dentaries and postcrania of Callorhinus gilmorei, and a partial dentary of early Pleistocene age identified as Callorhinus sp. The aforementioned material is ascribed to C. gilmorei due to the incipient single-rooted condition of the p1–2, retention of double-rooted p3–m1, and overall small size. The dentary identified as Callorhinus sp. exhibits a more derived pattern of tooth morphology, including single-rooted p1–p4 (and double-rooted m1), larger size than C. gilmorei, and in the size range of extant Callorhinus ursinus (which typically exhibit fused roots on all postcanine teeth). Fusion of postcanine roots began with the p2 and continued posteriorly, and is likely an adaptation to accommodate crowded teeth anteriorly in the jaws. Callorhinus gilmorei has previously been reported from the upper Pliocene of southern California and Japan, and this new record extends the range of this taxon further north in the Northeast Pacific. Callorhinus sp. is the most complete pinniped fossil to be described from the early Pleistocene of the Northeast Pacific. The wide biogeographic range of Callorhinus during the Pliocene and Pleistocene documents the persistence of this taxon, potentially as a Pliocene-Holocene anagenetic lineage. This highlights the antiquity of the Callorhinus lineage, which has persisted in the Northeast Pacific since the Pliocene, establishing it as the oldest and earliest diverging crown otariid.
... Otariids occur in the North Pacific Ocean and Southern Hemisphere and are found from tropical waters in the eastern Pacific to polar regions (Churchill et al. 2014;Berta et al. 2018). Although the systematics and phylogeny of the family have been extensively studied for over 100 years (Sclater 1897;Scheffer 1958;Wynen et al. 2001;Deméré et al. 2003;Árnason et al. 2006;Yonezawa et al. 2009;Berta and Churchill 2012;Nyakatura and Bininda-Emonds 2012;Churchill et al. 2014;Berta et al. 2018), several relationships, in particular those within Arctocephalus, the most diverse (eight species) otariid genus, remain unclear (Yonezawa et al. 2009;Berta and Churchill 2012). For example, older studies based on morphology suggested grouping the fur seals (Callorhinus ursinus and Arctocephalus spp.) in the Arctocephalinae, which are characterized by small body size and thick pelage, and the sea lions in the Otariinae, which are characterized by larger body size and reliance on blubber rather than fur for thermal insulation (Berta and Deméré 1986; see review in Berta et al. 2018). ...
... Our results strongly support C. ursinus as a sister species to all other Otariidae, which was also supported by other phylogenetic studies (Wynen et al. 2001;Árnason et al. 2006;Yonezawa et al. 2009;Nyakatura and Bininda-Emonds 2012;Berta and Churchill 2012;Churchill et al. 2014), thoroughly refuting the validity of the subfamilies Arctocephalinae and Otariinae. It is noteworthy that, considering our whole-genome phylogenies and other recent studies, Callorhinus diverged ca. 4 myr before the diversification of the rest of the family (Yonezawa et al. 2009;Boessenecker 2011;Nyakatura and Bininda-Emonds 2012;Berta et al. 2018). ...
... Our study results offer robust support for the existence of the Northern Sea Lion clade, proposed by Churchill et al. (2014), consisting of Zalophus and Eumetopias (see Fig. 1). This Northern clade has been recovered in several previous studies (see Wynen et al. 2001;Árnason et al. 2006;Higdon et al. 2007;Yonezawa et al. 2009;Berta and Churchill 2012;Churchill et al. 2014;Berta et al. 2018), that also supported the monophyly of Zalophus (Wolf et al. 2007;Yonezawa et al. 2009;Berta and Churchill 2012;Churchill et al. 2014;Berta et al. 2018). Our analysis, however, recovered an unexpected but fully supported and close relationship between E. jubatus and Z. californianus with Z. wollebaeki as sister to them. ...
Article
The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance because of strong gene-tree species tree discordance. Divergence times estimates in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here we used high-coverage genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus. Our data support a relatively recent trans-hemispheric dispersal at the base of a southern clade, which rapidly diversified into six major lineages between 3 to 2.5 Ma. Otaria diverged first, followed by Phocarctos and then four major lineages within Arctocephalus. However, we found Zalophus to be non-monophyletic, with California (Z. californianus) and Steller sea lions (Eumetopias jubatus) grouping closer than the Galapagos sea lion (Z. wollebaeki) with evidence for introgression between the two genera. Overall, the high degree of genealogical discordance was best explained by incomplete lineage sorting resulting from quasi-simultaneous speciation within the southern clade with introgresssion playing a subordinate role in explaining the incongruence among and within prior phylogenetic studies of the family.
... Previous studies using morphology (Repenning & Tedford 1977;Berta & Deméré 1986;Brunner 1998) and molecular sequence data (Wynen et al. 2001) have attempted to determine phylogenetic relationships among taxa and to understand the history of otariid diversification. Unfortunately, the otariid fossil record is depau-perate, with a very limited number of recovered specimens available for study. ...
... In addition to the problems of a depauperate fossil record, there currently is uncertainty regarding otariid phylogenetic relationships (e.g., Berta & Deméré 1986;Lento et al. 1995;Wynen et al. 2001), with major questions concerning the monophyly of fur seals (Arctocephalinae) and sea lions (Otariinae), and even the monophyly of the genus Arctocephalus (Robinette & Stains 1970;Repenning et al. 1971;Lento et al. 1995). Proposed avenues for resolving some of these phylogenetic difficulties include expansion of the meager otariid fossil record and careful examination of extant and fossil taxa for phylogenetically useful characters. ...
... Callorhinus is sister taxon to a clade consisting of a monophyletic Arctocephalus species complex and a monophyletic Otariinae. The basal position of Callorhinus is also supported by molecular data (Wynen et al. 2001;Lento pers. comm.). ...
Article
Full-text available
New crania, dentitions, and postcrania of the fossil otariid Thalassoleon mexicanus are described from the latest Miocene-early Pliocene Capistrano Formation of southern California. Previous morphological evidence for age variation and sexual dimorphism in this taxon is confirmed. Analysis of the dentition and postcrania of Thalassoleon mexicanus provides evidence of adaptations for pierce feeding, ambulatory terrestrial locomotion, and forelimb swimming in this basal otariid pinniped. Cladistic analysi s supports recognition of Thalassoleon as monophyletic and distinct from other basal otariids (i.e., Pithanotaria, Hydrarctos, and Callorhinus). Re-evaluation of the status of Thalassoleon supports recognition of two species, Thalassoleon mexicanus and Thalassoleon macnallyae, distributed in the eastern North Pacific. Recognition of a third species, Thalassoleon inouei from the western North Pacific, is questioned.
... Szapkievich et al. (1999) compared nine serum protein systems from two O. flavescens rookeries from Uruguay and Patagonia. Wynen et al. (2001) analysed the phylogenetic relationships and the historical biography of the Family Otariidae for what they sampled 16 species of eared seals. ...
... The 19 A. australis DNA samples used in PCR amplification were successfully amplified. Sequences for O. flavescens and A. australis from Punta San Juan, Peru´(PSJ) were obtained from the GenBank (accession numbers: AF380906-10, AF380901-5, respectively) (Wynen et al. 2001) and consisted in a 360 bp segment of the 5 0 end of the mitochondrial cytochrome b gene. In the statistical comparisons between oceans, we reduced the size of Atlantic sequences from 445 to 360 bp taking into account that position 1 of the 360 bp fragments from GenBank corresponds to position 32 in the 445 bp sequences. ...
... 2). Haplotypes B, C, and D were related by a single base-pair substitution to haplotype A. Wynen et al. (2001) found two haplotypes with a length of 360 bp and two polymorphic sites between them (Tab. 2). ...
Article
Genetic diversity and population structure of two species of South American pinnipeds, Otaria flavescens and Arctocephalus australis, from colonies located along the south-eastern coast of South America, were analysed using mitochondrial DNA haplotypes and compared with two populations of these species from the Pacific coast. A 445 base-pair segment, that included the tRNA-Glu gene (31bp) and the adjacent cytochrome b gene (414bp), was amplified using the polymerase chain reaction and sequenced directly. O. flavescens and A. australis showed six and seven haplotypes with 12 and 20 polymorphic sites, respectively. In the Atlantic Ocean there was an individual of A. australis that showed an haplotype that was highly divergent from the others. If this haplotype is excluded, the pattern of haplotype differentiation obtained for both species indicated a possible bottleneck that would have occurred 110,000 years ago, which also affected other pinnipeds. Colonies of the Atlantic and the Pacific did not share haplotypes. This result, based on a limited number of samples for the comparisons between oceans, suggests that populations from both oceans correspond to different evolutionarily significant units. O. flavescens on the Atlantic coast shows two clusters of breeding colonies in Uruguay and Patagonia, separated by a thousand kilometres. Colonies within clusters did not show significant differences in haplotype frequencies, but the difference between the clusters was significant, suggesting that they correspond to different conservation stocks.
... However, alozymes are not as sensitive as other molecular markers. Túnez et al. (2007) studied the population structure of this species by analysing mtDNA from a few colonies along the Atlantic coast and comparing their results with five sequences previously published from Peruvian populations (Wynen et al. 2001). They found no shared haplotypes between the Atlantic and Peruvian colonies, which suggests the existence of different ESUs in each ocean basin. ...
... Later Repenning et al. (1971) attributed species status to A. galapagoensis and emphasized the need for additional studies on A. australis. Túnez et al. (2007) compared the mtDNA of South American fur seals from colonies along the coasts of Argentina and Uruguay with five published sequences from Peru ( Wynen et al. 2001). As in the South American sea lion, fur seals from the colonies in the Atlantic and the Pacific oceans did not share haplotypes. ...
... The subantarctic fur seal Arctocephalus tropicalis suffered severe population reductions and local extinctions due to commercial exploitation. After sealing, pronounced population expansions and recolonization of historical sites, and probable colonization of new breeding sites occurred (Wynen et al. 2001), and the species was found outside its range in South America, Angola, New Zealand, Australia, South Africa and on several islands (for a review, see Bester & Reisinger 2010). Ferreira et al. (2008) analysed mtDNA control region sequences from vagrant subantarctic fur seals found on the Brazilian coast and from animals from the main breeding colonies. ...
Article
1. Most aquatic mammals have high dispersal potential, and there are often severe conservation concerns related to their legal or illegal harvesting. Therefore, eco-nomic, social and forensic factors often arise in decisions relating to their population management. Molecular markers are essential tools in modern conservation genet-ics, revealing previously unknown aspects of aquatic mammal behaviour, natural history, population structure and demography. Molecular markers also have been used to define management units, to recognize taxonomic units, to conduct forensic analyses and to control illegal wildlife trade, providing valuable information for decision-making in wildlife conservation and management. 2. We review studies published in peer-reviewed journals between 1993 and 2010, in which genetic approaches have been applied to conservation-related issues involving natural populations of 25 species of aquatic mammals in South America. These studies cover just 34% of the 70 aquatic mammal species recorded in South America. 3. Most of the studies are related to population structure, phylogeography, gene flow and dispersal movements. In addition, recent findings relate to evolutionarily significant units, management units, forensics and conservation policy.
... A poor understanding of pinniped evolutionary relationships has hampered our understanding of the diversity of adaptations and macroevolutionary patterns for aquatic feeding in this major carnivoran lineage. Recent advances in otariid taxonomy (Wynen et al., 2001;Arnason et al., 2006;Higdon et al., 2007;Dasmahapatra et al., 2009;Wolf et al., 2007;Yonezawa et al., 2009;Berta and Churchill, 2012) have clarified evolutionary relationships among sea lions and fur seals, at least for the most basal clades. Although otariid evolutionary relationships overall still lack consensus, northern fur seals [Callorhinus ursinus (Linnaeus 1758)] are consistently positioned as the most basal living otariid, and Steller sea lions (Eumetopias jubatus Schreber 1776) are also consistently placed in a basal position (Fig. 1). ...
... Therefore, if a biting feeding mode is dominant in extant Callorhinus, then through functional inference we can assign a biting feeding mode to extinct species of Callorhinus (i.e. C. gilmorei and Callorhinus sp.). Furthermore, since northern fur seals are consistently positioned as the most basal living otariid phylogenetically (Wynen et al., 2001;Arnason et al., 2006;Higdon et al., 2007;Dasmahapatra et al., 2009;Wolf et al., 2007;Yonezawa et al., 2009;Berta and Churchill, 2012), this supports our hypothesis that C. ursinus exhibits its ancestral feeding mode. New discoveries of transitional fossils, subsequent craniodental analyses (e.g. ...
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Feeding performance studies can address questions relevant to feeding ecology and evolution. Our current understanding of feeding mechanisms for aquatic mammals is poor. Therefore, we characterized the feeding kinematics and performance of 5 Steller sea lions (Eumetopias jubatus) and 6 northern fur seals (Callorhinus ursinus). We tested the hypotheses that both species use suction as their primary feeding mode, and that rapid jaw opening was related to suction generation. Steller sea lions used suction as their primary feeding mode, but also used a biting feeding mode. In contrast, Northern fur seals only used a biting feeding mode. Kinematic profiles of Steller sea lions were all indicative of suction feeding (i.e., a small gape, small gape angle, large depression of the hyolingual apparatus and lip pursing). However, jaw opening as measured by Gape Angle Opening Velocity (GAOV) was relatively slow in Steller sea lions. In contrast to Steller sea lions, the GAOV of Northern fur seals was extremely fast, but their kinematic profiles indicated a biting feeding mode (i.e., northern fur seals exhibited a greater gape, a greater gape angle, and minimal depression of the hyolingual apparatus compared to Steller sea lions). Steller sea lions produced both subambient and suprambient pressures at 45 kPa, respectively. In contrast, northern fur seals produced no detectable pressure measurements. Steller sea lions have a broader feeding repertoire than northern fur seals, which likely enables them to feed on a greater variety of prey, in more diverse habitats. Based on the basal phylogenetic position of northern fur seals, craniodental morphological data of the Callorhinus lineage, and the performance data provided in this study, we suggest that a northern fur seals may be exhibiting their ancestral feeding mode.
... Molecular work (Flynn et al., 2005, this volume;Arnason et al., 2006) suggests a closer relation between otariids and odobenids (forming the Otaroidea clade). Conversely, Figure 12.1 Composite phylogeny for extant pinnipeds (Wynen et al., 2001;Arnason et al., 2006). morphology-based work (Adam and Berta, 2002;Deméré et al., 2003) suggests a closer link between phocids and odobenids (Phocomorpha Clade). ...
... Because closely related species have the potential to be more similar in morphology or ecology, the independent contrasts method (Felsenstein, 1985) was used. Correlation analyses were conducted in COMPARE 4.6b (Martins, 2004) with the phylogeny shown in Figure 12.1 (Wynen et al., 2001;Arnason et al., 2006) and a significance value of p<0.05. ...
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Pinnipeds are a clade of secondarily aquatic arctoid carnivorans, including 34 extant species dispersed across most of the world's oceans. Extant species are separated into three families (Figure 12.1): Odobenidae (walruses, 1 species), Phocidae (seals, 19 species), and Otariidae (sea lions and fur seals, 14 species) and display a wide range of ecological diversity (Reeves et al., 2002). Predominantly, pinnipeds are generalist feeders. They are opportunistic, and their diets may vary annually, between colonies and between individuals within a colony (King, 1983; Sinclair and Zeppelin, 2002; Williams et al., 2007). However, several species have evolved more specialist feeding techniques: (1) Odobenus rosmarus is a suction feeder, using powerful facial musculature to produce forces large enough to extract molluscs from their shells (Adam and Berta, 2002); Erignathus barbatus (Phocidae) also uses suction feeding (King, 1983; Marshall et al., 2008); (2) Lobodon carcinophagus (Phocidae) is a filter feeder; it uses multicuspidate teeth to sieve out krill as water is expelled from the mouth; (3) Hyrdrurga leptonyx (Phocidae) feeds on large, warm-blooded prey such as penguins and seal pups (Adam and Berta, 2002). Reproductive strategies of the pinnipeds are also diverse. Otariids are universally dimorphic with large harems. Their young are weaned over long periods of up to 2 years whilst learning to forage (Kovacs and Lavigne, 1992; Schulz and Bowen, 2004). On the other hand, phocid young are relatively precocial (4–50 days weaning) and learn foraging skills after leaving their mothers. Phocids also show a diversity of mating strategies and degree of dimorphism (Schulz and Bowen, 2004). It has been hypothesised that this shorter time spent on land has allowed phocids to exploit a broader range of habitats, including polar regions (Kovacs and Lavigne, 1992; Schulz and Bowen, 2005). Odobenids show extremely long lactation times of three years. During this period, young walruses often accompany mothers on foraging trips.
... Wood Jones, 1925) are one of the few exceptions to this pattern and are the only fur seal species known to use benthic foraging exclusively (Arnould and Hindell 2001;Arnould and Kirkwood 2008). Their status as conspecific to epipelagic foraging Cape fur seals (Arctocephalus pusillus pusillus (Schreber, 1775)), from which they separated some 12 000 years ago (Wynen et al. 2001;Deméré et al. 2003), makes them an ideal candidate in which to investigate the effects of habitat type on population dynamics while controlling for phylogeny. ...
... This has been suggested as the reason for sea lions being generally larger bodied than fur seals . Australian fur seals are the only fur seal species known to employ an exclusively benthic foraging mode (Arnould and Hindell 2001), which may have selected for increased body size since migration from the Benguela upwelling region some 12 000 years ago (Wynen et al. 2001). Female growth rates were relatively rapid, with 87% of asymptotic length attained at age 3, which coincides with their age of sexual maturity (2-3 years; Gibbens et al. 2010) and, therefore, with Law's observation of puberty being attained at this length (Laws 1956). ...
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Postsealing population recovery rates of fur seals and sea lions have differed markedly, perhaps owing to habitat type. Australian fur seals (Arctocephalus pusillus doriferus Wood Jones, 1925) employ a benthic foraging mode similar to sea lions, and have exhibited similarly slow population recovery. Nonetheless, the population doubled in recent decades, suggesting a recent change in demographic rates. In the present study, the frequency and size of known-age females (n = 297) were used to create body growth and survivorship models. These were compared with models obtained in the 1970s before the recent population increase. Body growth, which is relatively rapid in comparison to other fur seal species, remains unchanged since the 1970s, suggesting that density-dependent effects are absent despite the population increases. Adult survival rates (weighted mean: 0.885) have increased greatly since the 1970s and are the likely mechanism of the recent increases. Total population abundance was estimated to be 4.5 times that of pups. Australian fur seals display high survivorship, rapid body growth, low fecundity, and low population growth rates; all are characteristics typical of benthic foraging sea lions rather than other fur seals.
... They do not found significant genetic differences between colonies, concluding that colonies belong to the same population in which gene flow currently occurs. More recently, Túnez et al. (2007) analyze mitochondrial DNA (mtDNA) cytb sequences in six colonies from northcentral Patagonia and Uruguay and compare their results with previously published sequences from a Peruvian colony (Wynen et al. 2001). They found no shared haplotypes between Atlantic and Peruvian colonies, suggesting the existence of different Evolutionary Significant Units (ESUs) in each ocean basin. ...
... Morphological and genetic studies support the idea that Peruvian colonies should be considered an ESU isolated from Atlantic populations: Túnez et al. (2007) using mtDNA cytb sequences analyzed the genetic diversity of the species in Cabo Polonio, Uruguay, and compared their results with available sequences from the Peruvian colony of Punta San Juan (Wynen et al. 2001). ...
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The model established for subsistence patterns of hunter-gatherer societies which inhabited the islands located southwards Tierra del Fuego argues that pinnipeds constituted the most important food resource. This general view is based on two fundamental points: (a) an increase in human carrying capacity due to energy importation produce through these marine mammals, (b) the independence of seal populations with respect to human activities, which guaranteed a sustained supply of animals to the human populations throughout the archaeological sequence. This model arises primarily from the evidence provided by the layer D of Túnel I archaeological site in the Beagle Channel, Tierra del Fuego Island. This chapter aims to make a reflection about this model. To do so, it brings together relevant information about pinnipeds representations in other archaeological sites of the Beagle Channel. In light of recent studies, it is noted that harvest strategies of seals would have been more variable than previously suggested, generating new questions about the relationship between humans and pinnipeds along occupational sequence of the Beagle Channel.
... Arctocephalus australis showed five haplotypes determined by 12 polymorphic sites. These haplotypes were compared with available sequences from the Peruvian colony of Punta San Juan (Wynen et al. 2001). None of them was shared between colonies. ...
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Analysing a 529 bp segment of the mitochondrial control region, we evaluated the role that Pleistocene glaciations may have had in shaping the genetic structure currently found in the two southernmost breedingareas of the South American fur seal, Arctocephalus australis. Additionally, we analysed if these two breedingareas correspond to different conservation units. We found 26 haplotypes in 54 individuals. Colonies from the Uruguayan breeding area did not show significant differences in haplotype frequencies, which suggest that they are remnants of a single ancient gene pool. The genealogical relationship between haplotypes revealed a pattern of phylogeographic structure with two main haplogroups corresponding to the different breeding areas. The analysis of molecular variance and the estimate of population divergence time also indicated significant genetic differences and a long period of isolation between Atlantic and Pacific colonies, suggesting that these breeding areas would correspond to different conservation units.
... The Otariidae evolved from the ancestral family (Enaliarctidae) about 11 Ma. The sea lion genera (Phocarctos, Neophoca, Zalophus, Eumetopias, and Otaria) and Arctocephalus species (fur seals) are thought to have diverged from Callorhinus (of only one species, the northern fur seal, C. ursinus) about 6 Ma (Wynen et al. 2001). Callorhinus remained in the northern hemisphere while the sea lions and fur seals dispersed to and diversified in the tropics and southern hemisphere. ...
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Abstract The majority of behavioural studies on pinnipeds, and indeed large mammals, have focused on the primary tactic due to the difficulty of studying alternative tactics that are more opportunistic. However, this limits our understanding of the nature and of the likely proximate factors that may drive the occurrence of alternative tactics and their relative importance in the mating system. I used a novel mobile technique with telemetry and Timed-Data Recorders, behavioural observations, measures of body composition and energy expenditure and microsatellite paternity analysis on 42 known-age adult male grey seals to measure the extent and success of behavioural variation and the proximate factors that may drive this variation. The study was conducted on Sable Island, Nova Scotia during the breeding seasons of 1997 to 2002. Using a mobile focal-animal technique I revealed much greater variation in behaviour than previously recognised. Diving was a substantial component of the behavioural repertoire of many male grey seals on Sable Island during the breeding season. Males engaged in both deep and shallow diving and I suggest that foraging occurred during deep dives. The probability of fertilization success for the primary tactic of engaging in consortship was 22% while the success of those males that exhibited the alternative tactic of mating with departing females was 7%. Although young males were less competitive than older males, some young males achieved success using the primary mating tactic (i.e., consort males) and some older males exhibited both primary and alternative tactics. When controlling for age, non-consort males had a lower body condition index and lower testosterone concentration than consort males suggesting that state was more important than age in determining performance. Males that expressed the primary mating tactic of consortship were larger in body size and arrived with absolutely more energy reserves and sustained breeding for longer. Males with a smaller percentage of body fat at capture expended more body protein as energy and acquired more supplemental energy. The behaviour and success of non-consort males may be energetically constrained due to the costly behaviour of movement. State played an important role in the expression of mating tactics and therefore success. Large body size provided an energetic advantage of greater endurance during the breeding season and may have also contributed to greater competitive ability at acquiring consortships. Alternative mating tactics in the grey seal mating system may have important implications for the pattern of gene flow and for the opportunity of sexual selection. Résume La majorité des études comportementales sur les pinnipèdes, et plus généralement sur les grands mammifères, s’est concentrée sur les tactiques principales en raison de la difficulté d’étude des tactiques alternatives qui sont plus opportunistes. Cependant, connaissant le succès des tactiques alternatives, ce type d’études limite notre compréhension de la nature et des facteurs proximaux qui pourraient conduire au développement de tactiques alternatives et leur importance relative dans le système d’accouplement. J’ai utilisé une approche mobile qui combine la télémétrie et les enregistreurs de plongées, les techniques énergétiques, les observations comportementales et les analyses de paternité par microsatellites sur 42 phoques gris mâles adultes d’âge connu pour mesurer l’étendue et le succès des variations comportementales et les facteurs proximaux qui pourraient engendrer ces variations. Cette étude a été conduite sur l’île de Sable, Nouvelle Ecosse, pendant les saisons de reproduction 1997 à 2002. Grâce à cette approche mobile, j’ai révélé des variations comportementales bien plus importantes que précédemment documenté. La plongée est un composant substantiel du répertoire comportemental de beaucoup de phoques gris sur l’île de Sable pendant la saison de reproduction. Les mâles effectuent à la fois des plongées profondes et peu profondes et je suggère que les plongées profondes correspondent à un comportement de chasse. La probabilité de succès de fertilisation pour la tactique principale de ‘conjoint’ est de 22% tandis que le succès des mâles qui pratiquent la tactique alternative en s’accouplant avec les femelles quittant la plage est de 7%. Bien que les jeunes mâles soient moins compétitifs que les mâles plus âgés, quelques jeunes mâles utilisent avec succès la tactique principale d’accouplement et quelques mâles plus âgés utilisent à la fois les tactiques principales et alternatives. Pour un même âge, les mâles ‘non-conjoints’ ont un indice de condition corporelle et une concentration de testostérone plus faibles, suggérant que l’état est plus important que l’âge dans la détermination de la performance. Les mâles ‘conjoints’ qui suivent la stratégie principale sont plus gros en taille, disposent de beaucoup plus de réserves énergétiques et prolongent leur reproduction plus longtemps. Les mâles ‘non-conjoints’ possèdent un plus faible pourcentage de graisse corporelle lors du début de la saison de reproduction dépensent plus de protéines corporelles comme source d’énergie et doivent acquérir plus d’énergie supplémentaire. Leur comportement et leur succès pourraient être contraints en terme d’énergie par un comportement coûteux de déplacement. L’état joue un rôle important dans l’expression de la tactique d’accouplement et donc dans son succès. Une grande taille corporelle fournit un avantage énergétique par la plus grange endurance pendant la saison de reproduction et pourrait aussi contribuer à une plus forte compétitivité dans la défens des femelles. Dans le système d’accouplement du phoque gris, les tactiques alternatives pourraient avoir d’importantes implications dans le schéma des flux géniques et de l’intensité de la sélection sexuelle.
... The "southern otariids" arrived in the eastern Pacific in the Late Miocene and then spread along the west and south eastern south Pacific (Yonezawa et al., 2009). These populations then invaded other lands and islands, such as South Africa, Australia, New Zealand and isolated islands in higher latitudes by following the West Wind Drift (Repenning et al., 1979;Yonezawa et al., 2009;Wynen et al., 2001). Yonezawa et al. (2009) suggest that the distribution pattern of Arctocephalus pusillus can be explained by vicariance as the ancestral population rapidly segregated in the Circum-Antarctic Ocean (Yonezawa et al., 2009). ...
Article
A phylogenetic analysis of the Langebaanweg seals was undertaken to better understand their relationships. The fossil phocid seals from Langebaanweg nest within the Lobodontini and form a clade that includes Ommatophoca rossii (Ross seal). The Langebaanweg seals' relationships are unresolved in both analyses. Two analyses were performed producing differing results. The prior weights analysis produced a clade that included the Ross seal (Ommatophoca rossii) + the Langebaanweg seals + the remaining Antarctic lobodontines. The implied weights analysis (k=3) produced a clade including the South American seals (Hadrokirus and Piscophoca) + the Ross seal (Ommatophoca rossii) + the Langebaanweg seals, which is part of the polytomy that includes the clade including the leopard seal (Hydrurga leptonyx) and the crabeater seal (Lobodon carcinophaga) and Acrophoca longirostis. In both analyses the monophyletic group LBW-F + LBW-D + LBW-A is retained while the monophyletic group LBW-C + LBW-B from the first analysis is replaced by the polytomy LBW-B + LBW-C + LBW-E in the second. The collapse of the monophyletic group LBW-C + LBW-B is due to its poor support (20), most likely as a result of LBW-C being incomplete caudally. Island hopping is proposed as a means for phocid seal migration to South Africa. The presence of islands along South Africa's west coast and phocid seal adaptation to a life independent of land and the use of ice as haul out sites lend support to this theory. During the Pleistocene, the decrease in local sea levels resulted in the loss of islands which may have resulted in the extinction of these seals over time.
... Lying on opposite sides of the South American continent, it is perhaps not surprising to find genetic differences between the Peruvian and Uruguayan populations, though whether this reflects complete isolation for a short period of time or a potentially much longer period of partial isolation, with limited gene flow occurring via more southern populations remains unclear. Our results support a preliminary analysis of mitochondrial DNA (Túnez et al. 2007), where sequences from Uruguay differed from published sequences from Peruvian seals (Wynen et al. 2001). Neutral genetic differentiation might be hastened by periodic bottlenecks due to El Niño Southern Oscillation (ENSO) events which can drastically reduce food availability and cause major population reductions (Glantz 1996;Majluf 1998). ...
... Previous genetic studies of the GFS have either included small numbers of individuals to elucidate wider species relationships (Wynen et al. 2001;Dasmahapatra et al. 2009) or focused on identifying vagrant animals using a handful of mtDNA sequences (e.g., Félix et al. 2001;Capella et al. 2002;Aurioles-Gamboa et al. 2004;Yonezawa et al. 2009;Montero-Cordero et al. 2010). ...
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Females of many pinniped species generally exhibit strong fine-scale philopatry, but it is unclear over what spatial scale this behavior may translate into genetic population structure. We conducted a population genetic survey in the Galapagos fur seal, Arctocephalus galapa-goensis, an endangered pinniped endemic to a small geographic range in the northwest of the Galapagos archipelago. To assess patterns of genetic diversity levels and population differentiation, we analyzed part of the mitochondrial control region (mtDNA) and 18 mi-crosatellites DNA markers. We detected similar levels of genetic diversity to many other pinniped species (h = 0.86, p = 0.012, A = 7.44) despite severe anthropogenic exploitation in the nineteenth century and recurrent population crashes due to recent climatic perturbations associated with El Niño Southern Oscillation events. We further found remarkably strong fine-scale matrilineal population structure , with 33.9 % of the mtDNA variation being partitioned among colonies separated by as little as 70 km swimming distance. In contrast, population structure inferred from nuclear markers was weak. Our findings provide further evidence that natal philopatry can translate into fine-scale genetic population structure in highly mobile species. We discuss the relevance of our results for the fine-scale conservation management of this species with a very restricted geographic range.
... However, genetic discontinuities have been observed in most species (O'Corry-Crowe, 2008 andHoffman et al., 2009 Note: 1. Wynen et al. (2000Wynen et al. ( , 2001 Garza and Williamson (2001). Rare alleles loss and He/Heq are available in the software bottleneck (Cornuet & Luikart, 1996). ...
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Aim Many pinniped species have experienced drastic demographic changes due to their interaction with humans. Most studies, however, have failed to detect recent bottlenecks in otariids from genetic data. The South American Sea Lion Otaria flavescens have a long history of population changes associated with interglacial expansion and hunting to almost extinction. This study aimed at investigating these different demographic fluctuations integrating population genetics and phylogeographic approaches. Location Pacific coast of South America. Methods Eighty‐five samples from the Chilean coast were collected. Eight microsatellite loci were genotyped, and D‐Loop mitochondrial DNA (mtDNA) sequenced. Genetic diversity was assessed, and tests of recent genetic bottlenecks were performed. Past demographic changes were inferred based on neutrality tests, adjustment of a sudden expansion model and Bayesian skyline plots. The magnitude and timing of the different population size changes were further investigated through approximate Bayesian computation (ABC) of coalescent inferences. Results The mtDNA shows relatively high diversity (h = 0.98 and π = 0.01) compared to most otariids, corroborates the divergence between Pacific and Atlantic populations, around 80,000 years ago (ya), and revealed a secondary contact zone in the Magellan strait. Microsatellite data support a second genetic discontinuity at 40°S, associated with post‐glacial colonization of Patagonia. ABC analyses confirmed that glaciation affected the effective population size (Ne) all along the Pacific Coast, between ~50,000 and 15,000 ya. A strong reduction of Ne was also inferred for the hunting period (73–66 ya from sampling). Main conclusions O. flavescens shows clear signatures of susceptibility to climatic and anthropogenic disturbances and a spatial genetic structure that should be taken into account in the context of management and conservation policies. Yet, despite a recent history of demographic bottlenecks, the genetic diversity remains high, likely a consequence of the demographic dynamics in otariids, characterized by large and connected metapopulations.
... Submissive calls and guttural threats described in AFS were not found in CFS. Therefore, it appears that since their split (considered as phylogenetically recent, less than 18000 y/a [78,79]) some modifications occurred in the composition of their vocal repertoire, probably due to differences in their environment and/or social structure. Nevertheless, vocalizations from AFS and CFS have kept vocal similarities. ...
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Communication is fundamental for the survival of animal species as signals are involved in many social interactions (mate selection, parental care, collective behaviours). The acoustic channel is an important modality used by birds and mammals to reliably exchange information among individuals. In group-living species, the propagation of vocal signals is limited due to the density of individuals and the background noise. Vocal exchanges are, therefore, challenging. This study is the first investigation into the acoustic communication system of the Cape fur seal (CFS), one of the most colonial mammals with breeding colonies of hundreds of thousands of individuals. We described the acoustic features and social function of five in-air call types from data collected at two colonies. Intra-species variations in these vocalizations highlight a potential ability to convey information about the age and/or sex of the emitter. Using two classification methods, we found that the five call types have distinguishable frequency features and occupy distinct acoustic niches indicating acoustic partitioning in the repertoire. The CFS vocalizations appear to contain characteristics advantageous for discrimination among individuals, which could enhance social interactions in their
... Hoy se cuenta con más información sobre el ciclo anual de ocupación de la isla y sobre los hábitos alimenticios y el comportamiento de estos animales, así como de los efectos catastróficos, como la mortandad de crías por huracanes, como Darby que azotó a Isla Guadalupe en julio de 1992 y que mató 33% de las crías (Gallo-Reynoso, 1994). También sería de gran valor realizar estudios más detallados sobre la sistemática de la especie (Wynen et al., 2001 ). Es necesario continuar monitoreando y censando a la población dado el crecimiento tan acelerado que muestra la especie. ...
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Las poblaciones de elefante marino, Mirounga angustirostris, y de lobo fino de Guadalupe, Arctocephalus townsendi, fueron casi exterminadas en isla Guadalupe durante el siglo XIX. En esta isla sobrevivieron individuos de ambas especies, a partir de los cuales sus poblaciones se han recuperado exitosamente. La población de elefante marino se recuperó de una manera explosiva y hoy en día hay más de 150,000 en las colonias de México y los Estados Unidos; en Guadalupe, cerca de 30,000 individuos en el punto máximo del periodo reproductivo (enero-febrero) y esta cifra se ha mantenido estable al menos durante los últimos 30 años. El lobo fino de Guadalupe es el único representante del género Arctocephalus en el hemisferio norte, y su población se ha recuperado de una manera más paulatina. Sólo se reproduce en la costa oriental de la isla y su número actual alcanza los 12,000 individuos y cuenta con una nueva colonia reproductora en la Isla San Benito del Oeste. Por su parte la población del lobo marino de California, Zalophus californianus, es de aproximadamente 1,500 individuos, pero ha mostrado fluctuaciones importantes sin causa aparente. En isla Guadalupe se reproduce en dos sitios, su principal colonia se halla al sur, en el Islote Zapato (Isla de Afuera) y con un número menor de animales, en el Cantil Blanco, cerca de Roca Vela, en la parte norte de la isla; probablemente esta población tenga un cierto grado de aislamiento con respecto a las poblaciones de lobos marinos de las islas cercanas a la Península de Baja California. Isla Guadalupe es muy importante en la historia de la conservación a nivel mundial dado que fue el primer lugar que decretó el gobierno mexicano, en 1922, como reserva para la protección y conservación de los elefantes marinos y de los lobos finos; un decreto posterior, de 1928, declaró la protección de la isla como Zona Reservada para la Caza y Pesca de Especies Animales y Vegetales.
... Anatomically, the similarities between the genus Arctocephalus (southern fur seal) and Otariinae is greater than those between Arctocephalus and Callorhinus, northern fur seals (Yonezawa et al., 2009). The Wynen et al. (2001) study of the partial sequence of (mt) cytochrome b and D supports the basal position of Callorhinus ursinus within the phylogenetic tree of Otariidae and questions the monophyly of both the genus Arctocephalus and the subfamily Otariinae. The present study will not detail the intra-and inter-relationships among Otarioidae subgroups and species. ...
... Growth and body-size estimates can be used for monitoring the effects of population pressures and changes in the quality of the habitat of marine mammals (Bester BODY MEASUREMENTS OF SOUTH AFRICAN FUR SEALS and Van Jaarsveld, 1994). Within the Otariidae (fur seals and sea lions) quantitative descriptions of growth in body length based on animals aged from tooth structure, or on animals of known-age (i.e., animals tagged or branded as pups), are available for several species of fur seals and sea lions including the Australian fur seal (Arctocephalus pusillus doriferus) (Arnould and Warneke, 2002) which is very closely related to the South African fur seal (Wynen et al., 2001); the New Zealand fur seal (Arctocephalus forsteri) (Dickie and Dawson, 2003;McKenzie et al., 2007), the subantarctic fur seal (Arctocephalus tropicalis) (Bester and Van Jaarsveld, 1994), the Antarctic fur seal (Arctocephalus gazella) (Payne, 1979;Krylov and Popov, 1980;McLaren, 1993), the Northern fur seal (Callorhinus ursinus) (Scheffer and Wilke, 1953;Bychkov, 1971;Bigg, 1979;Lander, 1979;McLaren, 1993;Bigg, 1992, 1996) and the sea lions, Eumetopias jubatus, the Steller sea lion (Fiscus, 1961;Thorsteinson and Lensink, 1962;Calkins and Pitcher, 1983;Loughlin and Nelson, 1986;McLaren, 1993;Winship et al., 2001), and Otaria byronia, the South American sea lion (Rosas et al., 1993). ...
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Morphology, relative size and growth of the South African fur seal or Cape fur seal, Arctocephalus pusillus pusillus, from the coast of southern Africa are described and comparisons made to data available on the closely related Australian fur seal (Arctocephalus pusillus doriferus) and the New Zealand fur seal (Arctocephalus forsteri). Useful information can be gained from body measurements of seal carcasses provided canine teeth are extracted for aging. External body measurements (12 linear variables) were examined in relation to standard body length (SBL) and chronological age (y) using linear regression and non-linear least squares fitting as appropriate. Animals ranged from < 1 month to > 12 y. Of the 149 animals in the study, 39 were animals of known-age based on tagging; 34 were aged from highly reproducible counts of incremental lines observed in the dentine of upper canines (i.e., range 1-10 y); 10 were identified as adults 12 y (i.e., pulp cavity of the upper canine closed); and 66 were not aged. At birth, male South African fur seals are 35% (c. 69 cm) of their mean adult size. At puberty, they are 57% (c. 113 cm). The foreflippers measure 25-26% (c. 18 cm) of standard body length (SBL) in pups, and 24% (c. 48 cm) of SBL in adults. The hind flippers are considerably shorter, measuring 19% (c. 13 cm) in pups, and 14.5% (c. 29 cm) in adults. Axillary girth is usually about 57-67% of SBL. Growth of SBL was rapid during the early postnatal period with a significant growth spurt occurring at the onset of puberty (2-3 y). The rate of growth slowed significantly between 6 and 7 y. Social maturity was reached at about 9 to 10 y. Growth slowed thereafter. The mean SBL for aged males >10 y and unaged animals > 200 cm was 199 cm. Relative to SBL, facial variables and the fore/hind limbs scaled with negative slope relative to SBL or were negatively allometric; tip of snout to genital opening scaled with positive slope; and tip of snout to anterior insertion of the foreflipper was positively allometric. Relative to age, body variables scaled were negatively allometric. SBL was found to be a rough indicator of age and age group. The growth kinetics of juvenile and adult the South African fur seal and the Australian fur seal are best described by the logistic and double exponential (Gompertz) models rather than the exponential von Bertalanffy model. Australian fur seals grow at a faster rate but asymptotic maximum sizes are similar in South African and Australian fur seals.
... The fur seal and sea lion species that survived historical sealing did so only in dramatically reduced numbers in highly restricted locations. For example, the Antarctic fur seal (now the most abundant otariid; Table 1) was thought to be extinct from overharvesting; however, a few small populations were found on isolated islands (Wynen et al., 2001). Harvesting of otariids is now limited to subsistence harvest from first nations in the North Pacific (predominately of Northern fur seals) and commercial harvests of Cape fur seals in Namibia (Cumming, 2015). ...
... However, the nature of this process remains poorly understood. Available information is based on studies of phylogenetical relationships and the geographical distribution of this and related species (Wynen et al., 2001), as well as on genetic analyses of the historical relationship among different populations of O. flavescens (Túnez et al., 2007;Artico et al., 2010;Oliveira et al., 2017). After the sea lion had colonized the southern Atlantic coasts, the Pleistocene glaciations in the Quaternary period closed the sea connection between the oceans, leading to the interruption of gene flow and to the emergence of two isolated populations after several thousands of years (Oliveira et al., 2017). ...
Article
The Pleistocene glacial period shaped the current genetic structure of numerous species. The last glacial dynamics has been proposed to have split the South American sea lion, Otaria flavescens, into two Evolutionarily Significant Units (ESUs), one on each side of the continent. However, previous studies have not provided genetic information on colonies found along 3000 km of coastline of the southernmost limit of the species distribution, where gene flow could occur. We conducted an exhaustive phylogeographical analysis of O. flavescens using a mtDNA marker, including, for the first time, data from colonies living south of latitude 45° S, in the Argentinian provinces of Santa Cruz and Tierra del Fuego. Our results indicated the presence of five Conservation Units across the distribution range of O. flavescens and suggest that the Patagonian population must have expanded about 150 000 BP. We found evidence for gene flow across the entire species range, supporting a scenario of secondary contact in Tierra del Fuego where representatives of the oldest lineages coexist. The presence of gene flow between oceans leads us to reject the assumption of complete reciprocal monophyly for mtDNA between the presumed ESUs, suggesting that the species constitutes a single Evolutionarily Significant Unit.
... Anatomically, the similarities between the genus Arctocephalus (southern fur seal) and Otariinae is greater than those between Arctocephalus and Callorhinus, northern fur seals (Yonezawa et al., 2009). The Wynen et al. (2001) study of the partial sequence of (mt) cytochrome b and D supports the basal position of Callorhinus ursinus within the phylogenetic tree of Otariidae and questions the monophyly of both the genus Arctocephalus and the subfamily Otariinae. The present study will not detail the intra-and inter-relationships among Otarioidae subgroups and species. ...
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The disagreement surrounding the relationship within pinnipeds as well as their phylogenetic affinities still remains unresolved. Molecular-based studies neglect significant morphological data and ignore the entire fossil record, which demonstrates why there are such contradicting results from morphology-based studies. There still remains a difference of opinion about the origin of pinnipeds, with research supporting origination from either Ursid (bear-like) or Mustelid (weasel-like) ancestors, even extending down to familial and subfamilial levels. This study examines certain morphological characters in the three pinniped families: Otariidae (sea lions and fur seals), Odobenidae (walruses), and Phocidae (true seals), with extra emphasis on the four phocid subfamilies: Phocinae, Monachinae, Cystophorinae, and Devinophocinae. Morphological characters of the cranium (skull, dentition and mandible) and post cranium (humerus and femur) are the basis for understanding pinnipeds’ movement, body size, and sexual dimorphism, and all are ignored when only molecular analyses are used. Biomolecular based studies involve larger sample sizes and incorporate more phylogenetic characters, but ignore the significant data from the fossil record (which can only be examined through morphology). Therefore, the origin of pinnipeds cannot be resolved by depending only on molecular (genetic) or morphological approaches independently and future studies need to integrate both morphology and molecular data.
... Repenning et al. (1971) accorded them subspeci c status based on separate geographic ranges and one cranial character (the larger crest between the mastoid and jugular processes of the exoccipital in the CFS). Very low genetic divergence indicates that the two groups split relatively recently (<18000 y/a), with the AFS being the more recently established (Wynen et al., 2001). Based on molecular analyses there is no evidence for signi cant subpopulations within either subspecies. ...
... Actualmente, se piensa que el grupo Pinnipedia es un grupo artificial, proviniendo las subfamilias Otariidae y Odobeniidae de un ancestro de Ursidae, y Phocidae del mismo ancestro que Mustelidae (Berta & Sumich, 1999). Además de esto, también están en discusión los dos géneros en los que se encuentran divididos los otáridos debido a los escasos caracteres que determinan esta división (presencia/ausencia de una segunda capa de pelo y la presencia de 5 ó 6 caninos superiores; Wynen, 2001). Estudios recientes sugieren que la familia Otariinae y los géneros Arctocephalus y Callorhinus forman una politomía, rechazando la teoría monofilética antes sustentada (Berta & Sumich, 1999). ...
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Female South American fur seals breeding on land, tend to choose sites where they can give birth to their young undisturbed, and where the probability of survival for their newborn pup is maximized. Heat stress, density and habitat availability strongly limits the range of places where they can breed. This study analyzes habitat use selection patterns for pupping sites in female South American fur seals (Arctocephalus australis – SAFS hereafter) at the Punta San Juan (PSJ) guano reserve in Ica, Peru (15°22’ Lat. S). Recent changes in population density and beach topography resulting from two major natural events (the 1997/98 ENSO and the Nazca earthquake in 1996, respectively) allowed quantification of changes in breeding habitat selection patterns of SAFS at PSJ. Female density, habitat type, availability and preference for pupping sites during eight breeding seasons (BS): 1990-1994, 1997, 2004-2005 were compared. Although three tendencies were found for female density, in each of these three periods each year had to be analyzed separately (Kruskal Wallis, K=220.4, p<0.0001, !<0.05). Habitat availability before and after the 1996 earthquake did not vary ("2 (2, 1354) =2.14, != 0.05). Habitat preference for pupping was measured with Ivlev’s index (E; with a -1 to +1 range), showing that Damp habitats are always used for pupping, independently of changes in density (E= 0.24-0.39), meanwhile a linear regression (2-way scatterplot) between the use of Dry and Intertidal habitats and density showed that Dry habitats are preferred in high density years (r2=0,595) and Intertidal habitats preferred in low density years (r2=0,431). Therefore, with unlimited access to intertidal areas, females avoid pupping in dry areas away from the water, thus suggesting wet intertidal areas are the preferred and perhaps optimal pupping sites for female SAFS at PSJ. Only when population density and competition for these wet spots are high, female fur seals will be forced to pup in dry areas where they suffer heat stress and are forced to make thermoregulatory movements that endanger their pups lives.
... The remaining populations were highly fragmented and reduced in their distribution, and they underwent subsequent reductions in genetic diversity (Weber et al. 2000;Wynen et al. 2000;Pastor et al. 2004;Schultz et al. 2009). All extant fur seal and sea lion species have survived population bottlenecks, with different degrees of severity (Reeves et al. 1992;Stewart et al. 1993;Wynen et al. 2001;Nowak 2003). ...
Article
The New Zealand fur seal (Arctocephalus forsteri) passed through a population bottleneck due to commercial sealing during the eighteenth to nineteenth centuries. To facilitate future management options, we reconstructed the demographic history of New Zealand fur seals in a Bayesian framework using maternally inherited, mitochondrial DNA sequences. Mitogenomic data suggested two separate clades (most recent common ancestor 5000 years ago) of New Zealand fur seals that survived large-scale human harvest. Mitochondrial haplotype diversity was high, with 45 singletons identified from 46 individuals although mean nucleotide diversity was low (0.012 ± 0.0061). Variation was not constrained geographically. Analyses of mitogenomes support the hypothesis for a population bottleneck approximately 35 generations ago, which coincides with the peak of commercial sealing. Mitogenomic data are consistent with a pre-human effective population size of approximately 30,000 that first declined to around 10,000 (due to the impact of Polynesian colonization, particularly in the first 100 years of their arrival into New Zealand), and then to 100–200 breeding individuals during peak of commercial sealing.
... The role of Neophoca palatina in the evolution of Australasian sea lions is unclear. Molecular and total evidence phylogenetic analyses have generally had problems resolving the position of Neophoca within Otariidae (Wynen et al., 2001;Árnason et al., 2006;Higdon et al., 2007;Churchill et al., 2014a), although Yonezawa et al. (2009) recovered Neophoca as the sister taxon to Phocarctos. If Neophoca is indeed the sister taxon to Phocarctos, than the presence of N. palatina in New Zealand suggests that the Neophoca and Phocarctos clade may have originated in New Zealand. ...
Article
The Otariidae (fur seals and sea lions) are an important and highly visible component of Southern Hemisphere marine mammal faunas. However, fossil material of Southern Hemisphere otariids is comparatively rare and often fragmentary. One exception is the Pleistocene sea lion Neophoca palatina King, 1983a, which is known from a nearly complete skull from the North Island of New Zealand. However, the phylogenetic affinities of this taxon are poorly known, and comparisons with other taxa have been limited. We provide an extensive redescription of Neophoca palatina and diagnose this taxon using a morphometric approach. Twenty measurements of the skull were collected for N. palatina , as well as for all extant Australasian otariids and several fossil Neophoca cinerea Perón, 1816. Using principal component analysis, we were able to segregate taxa by genus, and N. palatina was found to cluster with Neophoca according to overall size of the skull as well as increased width of the intertemporal constriction and interorbital region. N. palatina can be distinguished from all other Australasian otariids by its unusually broad basisphenoid. Discriminant function analysis supported referral of Neophoca palatina to Neophoca with very high posterior probability. These results confirm the treatment of Neophoca palatina as a distinct species of Neophoca and highlight the former broad distribution and greater tolerance for colder temperatures of this genus. These results also suggest that New Zealand may have played a pivotal role in the diversification of Southern Hemisphere otariid seals.
... Morphological and genetic studies support the idea that Peruvian colonies should be considered an ESU isolated from Atlantic populations: Túnez et al. (2007) using mtDNA cytb sequences analyzed the genetic diversity of the species in Cabo Polonio, Uruguay, and compared their results with available sequences from the Peruvian colony of Punta San Juan (Wynen et al. 2001). No haplotypes were shared between colonies. ...
Chapter
Marine ecosystems of southern South America are very rich in species of marine mammals, with 10 pinniped and 46 cetacean species reported up to date. This chapter starts with a short description on the recorded presence and conservation status of these marine mammal species in the area. Then, in separate sections, each one corresponding to a different species, the reader will find the state of art on studies about biology, population numbers and trends, mayor threats, conservation genetics and population structure of six of the most emblematic species, extensively studied in the last decades, that inhabit southern South America coasts and waters.
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In the traditional biogeographic model, the Galápagos Islands appeared a few million years ago in a sea where no other islands existed and were colonized from areas outside the region. However, recent work has shown that the Galápagos hotspot is 139 million years old (Early Cretaceous), and so groups are likely to have survived at the hotspot by dispersal of populations onto new islands from older ones. This process of metapopulation dynamics means that species can persist indefinitely in an oceanic region, as long as new islands are being produced. Metapopulations can also undergo vicariance into two metapopulations, for example at active island arcs that are rifted by transform faults. We reviewed the geographic relationships of Galápagos groups and found 10 biogeographic patterns that are shared by at least two groups. Each of the patterns coincides spatially with a major tectonic structure; these structures include: the East Pacific Rise; west Pacific and American subduction zones; large igneous plateaus in the Pacific; Alisitos terrane (Baja California), Guerrero terrane (western Mexico); rifting of North and South America; formation of the Caribbean Plateau by the Galápagos hotspot, and its eastward movement; accretion of Galápagos hotspot tracks; Andean uplift; and displacement on the Romeral fault system. All these geological features were active in the Cretaceous, suggesting that geological change at that time caused vicariance in widespread ancestors. The present distributions are explicable if ancestors survived as metapopulations occupying both the Galápagos hotspot and other regions before differentiating, more or less in situ.
Chapter
The Galapagos fur seal (GFS; Arctocephalus galapagoensis) is the smallest seal species, endemic to the Galapagos archipelago and closely related to the South American fur seal, Arctocephalus australis. Females are highly site faithful. Genetic exchange between colonies happens predominantly through male dispersal. The species’ distribution overlaps with that of the Galapagos sea lion (Zalophus wollebaeki). The largest colonies exist on the western islands where cold, productive waters upwell. GFSs breed when upwelling is strongest, from August to December. They forage pelagically on organisms of the deep scattering layer, mostly cephalopods, myctophids, and bathylagids. These organisms migrate toward the surface when it gets dark, which brings them into the diving range of the GFS. Consequently, GFSs forage at night, and their foraging is strongly influenced by the lunar cycle. Females give birth to a single pup and nurse it usually for 2 years, but under poor environmental conditions may extend the time to weaning. If a female bears another pup during lactation, the newborn’s survival is seriously reduced. The extended period of maternal care lowers the reproductive rate. Moreover, in years of strong El Niño, offspring mortality is increased and even adult animals may die of starvation. The small distribution area and low population size make the GFS vulnerable to environmental disturbances, whether anthropogenic or natural like El Niño. Fishery interactions and the potential introduction of diseases are presently the greatest dangers. Tourism should be closely monitored and restricted to protect breeding sites.
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A bstract The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance pointing at strong gene-tree species tree discordance. Divergence times in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here we used high-coverage whole genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus . Our data support a relatively recent trans-hemispheric dispersal at the base of a southern clade, which rapidly diversified into six major lineages between 3 to 2.5 Mya. Otaria diverged first, followed by Phocarctos and then four major lineages within Arctocephalus . However, we found Zalophus to be non-monophyletic, with California ( Z. californianus) and Steller sea lions ( Eumetopias jubatus ) grouping closer than the Galapagos sea lion ( Z. wollebaeki ) with evidence for introgression between the two genera. Overall, the high degree of genealogical discordance was best explained by incomplete lineage sorting resulting from quasi-simultaneous speciation within the southern clade with introgresssion playing a subordinate role in explaining the incongruence among and within prior phylogenetic studies of the family.
Chapter
Attempts to understand the ecology of marine mammals and the ecological roles they play in marine ecosystems necessitate the knowledge of their abundance and the trends in their numbers. Yet, despite the high levels of interest in these animals, few good estimates exist for the population sizes of marine mammals. Many marine mammal populations are broadly dispersed much of the year, and virtually all species spend considerable amounts of their time under water and are therefore unavailable to normal census methods. Hence, estimation methods for almost all marine mammal species must include estimates for the unseen portions of a population under study. There are two basic approaches for determining marine mammal abundances: total population counts or counts of a sample of individuals and extrapolation to the whole population. Techniques for the repeated identification of marine mammals include flipper tagging, photo identification, radio and satellite telemetry, and a variety of molecular genetic methods. Growth rates vary considerably between species over several orders of magnitude. Among the common causes of natural mortality in marine mammal populations are predators, parasites, diseases, and trauma.
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Aquilaria tree species are naturally distributed in the Indomalesian region and are protected against over-exploitation. They produce a fragrant non-timber product of high economic value, agarwood. Ambiguous species delimitation and limited genetic information within Aquilaria are among the impediments to conservation efforts. In this study, we conducted comparative analysis on eight Aquilaria species complete chloroplast (cp) genomes, of which seven were newly sequenced using Illumina HiSeq X Ten platform followed by de novo assembly. Aquilaria cp genomes possess a typical quadripartite structure including gene order and genomic structure. The length of each of the cp genome is about 174 kbp and encoded between 89 and 92 proteins, 38 tRNAs, and 8 rRNAs, with 27 duplicated in the IR (inverted repeat) region. Besides, 832 repeats (forward, reverse, palindrome and complement repeats) and nine highly variable regions were also identified. The phylogenetic analysis suggests that the topology structure of Aquilaria cp genomes were well presented with strong support values based on the cp genomes data set and matches their geographic distribution pattern. In summary, the complete cp genomes will facilitate development of species-specific molecular tools to discriminate Aquilaria species and resolve the evolutionary relationships of members of the Thymelaeaceae family.
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Commercial harvest severely reduced the abundance of New Zealand fur seals (NZFSs; Arctocephalus australis forsteri), and the subspecies may have become regionally extinct in Western Australia (WA). NZFS populations are now expanding in WA and this study aimed to determine the origin of these populations and distinguish local recruitment from external recolonization. Mitochondrial cytochrome-b gene sequences were obtained from 137 NZFSs from breeding colonies in WA and South Australia (SA), and analyzed with sequences from Tasmania and New Zealand. Genetic differentiation among WA and SA populations was low, indicating extensive genetic exchange throughout this large region. Three unique haplotypes, however, were recorded from WA, supporting the local recruitment hypothesis. Moreover, a test for asymmetrical gene flow identified a predominance of migration from WA to SA, suggesting a role of WA NZFSs in the recovery of more heavily exploited SA NZFS populations. Significant genetic differentiation was evident between SA and Tasmania, indicating limited genetic exchange despite the close proximity of these populations. Examination of our data suggests NZFSs were not extirpated from WA, have retained unique genetic variants, and that peripheral, lowdensity populations may have had a role in the recolonization of heavily exploited populations.
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This is a 133-page bibliography listing a wide variety of published works bearing on the topic of mammalian hybridization. More than 2,300 publications are listed.
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The sighting of 2 individuals is the first report of a vagrant otarid in Chilean waters and also the first mention of this species for Chile. It is postulated that these animals arrived from Amsterdam or St. Paul Islands in the Indian Ocean assisted by the West Wind Drift in the Southern Ocean. This dispersal movement would be considered as the most extended done by an otarid, c 10 000 nautical miles. -from Authors
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To estimate approximate divergence times of species or species groups with molecular data, we have developed a method of constructing a linearized tree under the assumption of a molecular dock. We present two tests of the molecular clock for a given topology: two-cluster test and branch-length test. The two-cluster test examines the hypothesis of the molecular clock for the two lineages created by an interior node of the tree, whereas the branch-length test examines the deviation of the branch length between the tree root and a tip from the average length. Sequences evolving excessively fast or slow at a high significance level may be eliminated. A linearized tree will then be constructed for a given topology for the remaining sequences under the assumption of rate constancy. We have used these methods to analyze hominoid mitochondrial DNA and drosophilid Adh gene sequences.
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The Juan Ferná ndez fur seal (Arctocephalus philippii) was allegedly extremely abundant, numbering as many as 4 million prior to sealing which continued from the late 17th to the late 19th century. By the end of the sealing era the species was thought to be extinct until they were rediscovered at Alejandro Selkirk Island in 1965. Historic records would suggest that the species underwent a substantial population bottleneck as a result of commercial sealing, and from population genetic theory we predicted that the genetic variability in the species would be low. We compared the mtDNA control region sequence from 28 Juan Ferná ndez fur seals from two islands in the Juan Ferná ndez Archipelago (Chile). Contrary to expectation , we found that variation in the Juan Ferná ndez fur seals is not greatly reduced in comparison to other pinniped taxa, especially given the apparent severity of the bottleneck they underwent. We also determined minor, but significantly different haplotype frequencies among the populations on the two islands (Alejandro Selkirk and Robinson Crusoe Islands), but no difference in their levels of variability. Such differences may have arisen stochastically via a recent founder event from Alejan-dro Selkirk to Robinson Crusoe Island or subsequent genetic drift.
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A new species of fur seal, Callorhinus gilmorei, described from the San Diego Formation of southern California and Mexico, fills a critical stratigraphic and evolutionary gap in our knowledge of otariids. This Late Pliocene (Late Blancan) occurrence of Callorhinus represents the earliest record of modern otariid genera. Mandibular and dental characters distinguish Callorhinus gilmorei from the living northern fur seal, C. ursinus. Cladistic analysis supports a sister group relationship between Callorhinus and the Hemphillian fur seal 'Thalassoleon' macnallyae. Relationships among Arctocephalus species are unresolved. Re-evaluation of Hydrarctos lomasiensis from the Pliocene of Peru suggests that it is the primitive sister taxon of all modern otariids. Modern fur seals and sea lions form separate monophyletic groups.-Authors
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The structure and number of airborne vocalizations of Arctocephalus pusillus doriferus and A. forsteri were studied. Four types of calls were compared: the pupattraction call given by adult females; the female-attraction call given by pups; the high-intensity guttural threat given by adult males; and, the repetitive barking call given by adult males. Male A. fovsteri gave two additional threat calls not present in A. p. doriferus. The structure and number of the calls given by the two species are substantially different. They here then compared to the calls of other members of the genus for which data were available and it became evident there were two vocal types within the genus Arctocephalus. We believe this is the first time such a situation has been reported in mammals. In addition to vocalizations, data on behaviour and morphology are presented to show the enigmatic taxonomic position, between the fur seals and the sea lions, occupied by A. pusillus.
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Examination of serum samples from Arctocephalus spp. from southern Australia, New Zealand, and Macquarie I. revealed six transferrin types, which were assumed to be the products of four allelic genes, and two phenotypes of a haem-binding protein. Seals from South Neptune Is., Cape du Couedic, and the Recherche Archipelago were identical on these criteria; while those from Victoria were identical with those of Tasmania. This division is consistent with previous conclusions based on skull characters. The names there suggested for these two groups were A, forsteri and A. doriferus respectively. Transferrin types of New Zealand and Macquarie I. A. forsteri were not identical with those of Australian A. forsteri. It is suggested that fur seals may have been exterminated from South Australia and Western Australia and that recolonization was from New Zealand. Alternatively, these differences may indicate the existence of more than one species in these populations.