The phylogeny of Cetartiodactyla: the importance of dense taxon sampling, missing data, and the remarkable promise of cytochrome b to provide realiable species-level phylogenies

AGNARSSON, I.; MAY-COLLADO, L.J. 2008. The phylogeny of Cetartiodactyla: the importance of dense taxon sampling, missing data, and the remarkable promise of cytochrome b to provide realiable species-level phylogenies. Molecular Phylogenetics and Evolution 48:964-985.

Abstract. We perform Bayesian phylogenetic analyses on cytochrome b sequences from 264 of the 290 extant cetartiodactyl mammals (whales plus even-toed ungulates) and two recently extinct species, the "Mouse Goad" and the "Irish Elk". Previous primary analyses have included only a small portion of the species diversity within Cetartiodactyla, while a complete supertree analysis lacks resolution and branch lenghts limiting its utility for comparative studies. The benefits of using a single-gene approach include rapid phylogenetic estimates for a large number of species. However, single-gene phylogenies often differ dramatically from studies involving multiple datasets suggesting that they often are unrealiable. However, based on recovery of banchmark clades - clades supported in prior studies based on multiple independent datasets - and recovery of undisputed traditional taxonomic groups, Cytb performs extraordinarily well in resolving cetartiodactyl phylogeny when taxon sampling is dense. Missing data, however, (taxa with partial sequences) can compromise phylogenetic accuracy, suggesting a tradeoff between the benefits of adding taxa and introducing question marks. In the full data, a fez species with a short sequences appear misplaced, however, sequence lenght alone seems a poor predictor of this phenomenon as other taxa with equally short sequences were not conspicuously misplaced. Although we recommend awaiting a better supported phylogenetic hypotheses provided here represent the currently best available tool for comparative species-level studies within this group. Cytb has been sequenced for a large percentage of mammals and appears to be a reliable phylogenetic marker as long as taxon sampling is dense. Therefore, an opportunity exists now to reconstruct detailed phylogenies of most of the major mammalian clades to rapidly provide much needed tools for species-level comparative studies.

Use of carbon and nitrogen stable isotopes to study the feering ecology of small coastal cetacean populations in southern Brazil

HARDT, F.A.S.; CREMER, M.J.; JUNIOR, A.J.T.; BELLANTE, A.; BUFFA, G.; BUSCAINO, G.; MAZZOLA, S.; BARRETO, A.S.; MARTINELLI, L.A.; ZUPPI, G.M. 2013. Use of carbon and nitrogen stable isotopes to study the feering ecology of small coastal cetacean populations in southern Brazil. Biota Neotropica 13(4):90-98.

Abstract: Samples from individuals of the populations of Sotalia guianensis (Guiana) and Pontoporia blainvillei (Franciscana) dolphins living in the Babitonga Bay estuary (26° 28’ S/48° 50’ W), and samples from individuals of a second population of P. blainvillei from a nearshore area (26° 38’ S/48° 41’ W), were collected and analyzed along with their prey between 2000 and 2006, to determine the carbon and nitrogen stable isotope ratios and to verify differences in their feeding ecology. No differences were found in the median ð15N values of Guiana (15.2‰) and Franciscana (15.9‰) dolphins living in Babitonga Bay, nor of nearshore Franciscana (15.0‰) individuals, suggesting no variation in the trophic level of these populations. However, the lack of more information on the isotopic compositions of their putative prey in the nearshore areas prevents the ability to draw definitive conclusions on this issue. The estuarine Franciscana and Guiana dolphin populations presented mean ð13C values of approximately –15.7‰, which were not statistically different from nearshore Franciscana individuals (–14.8‰). Based on stomach content analyses of these species from a previous study, it was reported that there was little overlap in the diet of estuarine Franciscanas and Guiana dolphins. However, based on the similarity of the ð13C values between these two species and of their putative prey, it appears that in fact there is an overlap in the diet of these two species. Based solely on stable isotope analysis, it was not possible to differentiate between estuarine and nearshore Franciscana populations, making it difficult to conclude whether captured nearshore specimens were indeed yearlong residents of these areas. Finally, this study suggests that Franciscana and Guiana dolphin populations are sharing the same resources, mostly L. brevis, D. rhombeus, and S. rastrifer. Therefore, the combination of resource sharing and commercial exploitation of their prey makes these two cetacean species vulnerable.

External features of the dusk dolphin Lagenorhynchus obscurus (Gray, 1828) from Peruvian waters

WAEREBEEK, K.V. 1993. External features of the dusk dolphin Lagenorhynchus obscurus (Gray, 1828) from Peruvian waters. Estudos Oceanológicos 12:37-53.

Abstract. Individual, sexual and developmental variation is quantified in the external morphology and colouration of the dusky dolphin Lagenorhynchus obscurus from Peruvian coastal waters. No significant difference in body length between sexes is found (p = 0.09) and, generally, little sexual dimorphism is present. However, males have a more anteriorly positioned genital slit and anus and their dorsal fin is more curved, has a broader base and a greater surface area than females Although the dorsal fin apparently serves as a secondary sexual character, the use of it for sexing free-ranging dusky dolphins is discouraged because of high overlap in values. Relative growth in 25 body measurements is characterized for both sexes by multiplicative regression equations. The colouration pattern of the dorsal fin, flank patch, thoracic field, flipper stripe and possibly (X², p = 0.08) the eye patch, are independent of maturity status. Flipper blaze and lower lip patch are less pigmented in juveniles than in adults No sexual dimorphism is found in the colour pattern The existence of a discrete "Fitzroy" colour form can not be confirmed from available data. Various cases of anomalous, piebald pigmentation are described, probably equivalent to so-called partial albinism. Adult dusky dolphins from both SW Africa and New Zealand are 8-10 cm shorter than Peruvian specimens, supporting conclusions of separate populations from a recent skull variability study.

Interactions between Atlantic spotted (Stenella frontalis) and bottlenose (Tursiops truncatus) dolphins off Bimini, The Bahamas, 2003-2007

MELILLO, K.E.; DUDZINSKI, K.M.; CORNICK, L.A. 2009. Interactions between Atlantic spotted (Stenella frontalis) and bottlenose (Tursiops truncatus) dolphins off Bimini, The Bahamas, 2003-2007. Aquatic Mammals 35(2):281-291. DOI: 10.1578/AM.35.2.2009.281

Abstract. Interspecific interactions have been observed in a variety of social animal. Functional explanations include foraging, anti-predatory, and social advantages. These behaviours are poorly understood in marine mammals but are increasingly studied phenomena in sympatric populations. Resident Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas, have been the subject of ongoing photo-identification and behavioural studies since 2001. A lesser-known population of bottlenose dolphins (Tursiops truncatus) has been observed interacting with these S. frontalis since 2003. To examine the functional significance of these interactions, interspecific behaviours were documented with underwater video using focal animal sampling. Mating or sexual play were the primary activities observed in nearly 50% of interactions, with male T. truncatus as the initiators. Therefore, the most likely functional explanation for these interactions is social. We hypothesize that male T. truncatus which lack acess to T. truncatus females because of sexual immaturity or low social status seek copulations with S. frontalis females as an alternative.

Analysis of the distribution patterns of southern right whale off the southern Brazilian coast

SANTO, S.E.; FRANCO, D.; GROCH, K. 2013. Analysis of the distribution patterns of southern right whale off the southern Brazilian coast. Neotropical Biology and Conservation 8(3):143-149.

Abstract. The southern right whale, Eubalaena australis, is a migratory baleen whale that uses southern Brazilian waters as a nursery and breeding ground from June to November. This study aims to determine the distribution patterns and main aggregation sites of southern right whales off the southern Brazilian coast from around Santa Catarina Island to Osório, and to investigate the population distribution according to the coastline and bathymetric features. The methods consisted in obtaining geographical coordinates for each individual, sighted through helicopter expeditions over a transect along the coastline, conducted once a year in September, from 2001 to 2010. This data was used to generate a density estimate surface map of southern right whales using the Kernel Density Estimator. Additionally, a digital bathymetry was overlaid to the density estimate map. The results pointed out a region of high density estimate of southern right whales, located from 28°12’22”S, 48°39’25”W to 28°33’58”S 48°47’19”W, respectively, from Imbituba to Santa Marta Cape. The largest aggregations were observed where the shelf declivity is higher, as a result from the bathymetric lines of 10 m and 40 m being closer to each other, and where the coastline shows great amount of bays. We highlight the importance of monitoring the southern right whales distribution patterns observed in this study, aiming to identify possible habitat changes that can be indicative of disturbances on their populations.

Interactions between short-beaked common dolphin (Delphinus delphis) and the winter pelagic pair-trawl fishery off Southwest England (UK)

BOER, M.N.; SAULINO, J.T.; LEOPOLD, M.F.; RIJNDERS, P.J.H.; SIMMONDS, M.P. 2012. Interactions between short-beaked common dolphin (Delphinus delphis) and the winter pelagic pair-trawl fishery off Southwest England (UK). International Journal of Biodiversity and Conservation 4(13):481-499. doi: 10.5897/IJBC12.016

Abstract. During offshore and onshore studies (2004 to 2009), the interactions between pair-trawls and shortbeaked common dolphins (Delphinus delphis) were studied to better understand the impact of bycatch. A ‘hotspot’ area where pair-trawls overlapped with high dolphin abundance was identified. We made comparisons between boat-based data collected in absence and presence of pair-trawlers. The relative abundance and group-size of dolphins was significantly higher in the presence of pair-trawlers. Dolphins were observed associating with towing and hauling procedures. Significantly, more carcasses occurred in areas with hauling-activity than those without. Body-temperatures obtained from carcasses found near operating pair-trawlers indicated that bycatch mostly occurred at night. During necropsy studies, difficulties were encountered in identifying the fishing-gears responsible. Strandings data highlighted that the number of dead stranded dolphins was probably much higher than previously reported and there was a significant difference in the age and gender-composition of carcasses. Mature/sub-adult males appeared at greater risk from entanglement in pair-trawls offshore, whilst females with young appeared more vulnerable to inshore gillnets. Our findings show that the overlap between pelagic fisheries and the common dolphin hotspot is causing direct mortality through bycatch and, together with recent range-shifts, may have contributed to a localised decline of this species in this winter hotspot since 2007.

Cetaceans registered on the coast of Ilhéus (Bahia), northeastern Brazil

BATISTA, R.L.G.; SCHIAVETTI, A.; SANTOS, U.A.; REIS, M.S.S. 2012. Cetaceans registered on the coast of Ilhéus (Bahia), northeastern Brazil. Biota Neotropica 12(1):000-000.

Abstract. Stranded cetaceans have scientific value and may confirm the occurrence of some species or indicate their geographical distribution in an area. The collection of biological material can also contribute to improve the knowledge of the species or populations inhabiting certain areas. This study aimed to record live or dead cetaceans found ashore along the coast of Ilhéus, Bahia State, northeastern Brazil. Data were collected through a campaign called "SOS strandings, whales, porpoises and dolphins." Between 1997 and 1999 three hundred posters and five hundred folders were distributed to beach huts, shops, fishing associations and settlements, the city’s municipal government, the Brazilian Environmental Agency (IBAMA) and fire stations. During this campaign, which lasted until 2007 it was possible to record 38 cetaceans of ten species on the coast of Ilhéus: Physeter macrocephalus, Megaptera novaeangliae, Globicephala macrorhynchus, Orcinus orca, Peponocephala electra, Stenella clymene, Feresa attenuata, Ziphius cavirostris, Steno bredanensis and Sotalia guianensis. The greatest numbers of records were observed between 2000 and 2003, which was the period after the distribution of banners and posters. The majority of the carcasses were recovered near the city downtown area (<10 km) and there was not a relationship between the state of the carcasses and the distance from that area.

The looming crisis: interactions between marine mammals and fisheries

READ, A.J. 2008. The looming crisis: interactions between marine mammals and fisheries. Journal of Mammalogy 89(3):541-548.

Abstract. Direct fisheries interactions pose a serious threat to the conservation of many populations and some species of marine mammals. The most acute problem is bycatch, unintended mortality in fishing gear, although this can transition into unregulated harvest under some circumstances. A growing issue in some fisheries is depredation, in which marine mammals remove captured fish from nets or lines. Depredation reduces the value of catch and may lead to a greater risk of entanglement and the potential for retaliatory measures taken by fishermen. The conservation threat caused by direct fisheries interactions is most dire for small populations of cetaceans and dugongs. Immediate action is needed to assess the magnitude of bycatch, particularly in many areas of Africa and Asia where little work has been conducted. New and innovative solutions to this problem are required that take account of the socioeconomic conditions experienced by fishermen and allow for efficient transfer of mitigation technology to fisheries of the developing world.

A complete phylogeny of the whales, dolphins and even-toed hoofed mammals (Cetartiodactyla)

PRICE, S.A.; BININDA-EMONDS, O.R.P.; GITTLEMAN, J.L. 2005. A complete phylogeny of the whales, dolphins and even-toed hoofed mammals (Cetartiodactyla). Biology Review 80:445-473.

Abstract. Despite the biological and economic importance of the Cetartiodactyla, the phylogeny of this clade remains controversial. Using the supertree approach of matrix representation with parsimony, we present the first phylogeny to include all 290 extant species of the Cetacea (whales and dolphins) and Artiodactyla (even-toed hoofed mammals). At the family-level, the supertree is fully resolved. For example, the relationships among the Ruminantia appear as (((Cervidae, Moschidae) Bovidae) (Giraffidae, Antilocapridae) Tragulidae). However, due to either lack of phylogenetic study or contradictory information, polytomies occur within the clades Sus, Muntiacus, Cervus, Delphinidae, Ziphiidae and Bovidae. Complete species-level phylogenies are necessary for both illustrating and analysing biological, geographical and ecological patterns in an evolutionary framework. The present species-level tree of the Cetartiodactyla provides the first opportunity to examine comparative hypotheses across entirely aquatic and terrestrial species within a single mammalian order.