Delphinidae
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Recent papers in Delphinidae
Since the Moreno's et al. (2005)work, no study was done to update the distribution patterns of Stenella dolphins in the southwestern Atlantic Ocean. Ecological niche modeling was used to redefine the distribution patterns of Stenella... more
Since the Moreno's et al. (2005)work, no study was done to update the distribution patterns of Stenella dolphins
in the southwestern Atlantic Ocean. Ecological niche modeling was used to redefine the distribution patterns of
Stenella dolphins in this area of Atlantic Ocean. Maximum entropy method (Maxent) was employed to generate
models using a set of environmental variables as explanatory variables of the location records obtained by
sighting and accidental captures. All ecological niche models performed returned AUC values N0.9. Areas with
high environmental suitability for pantropical spotted dolphin (Stenella attenuata), Clymene dolphin (Stenella
clymene) and spinner dolphins (Stenella longirostris) are found in warm (N25 °C) and deep waters (≥1000 m).
High environmental suitability for Atlantic spotted dolphin (Stenella frontalis) seems to occur between 20.5°S
and 30°S in the southeastern Brazilian coastal waters. The projected maps of species distributions showed patterns
closely related to environmental changes at a fine spatial scale and added valuable information about the
offshore limits of those oceanic species. The results suggest that the different species of Stenella have distinct environmental
requirements in the southwestern Atlantic Ocean.
in the southwestern Atlantic Ocean. Ecological niche modeling was used to redefine the distribution patterns of
Stenella dolphins in this area of Atlantic Ocean. Maximum entropy method (Maxent) was employed to generate
models using a set of environmental variables as explanatory variables of the location records obtained by
sighting and accidental captures. All ecological niche models performed returned AUC values N0.9. Areas with
high environmental suitability for pantropical spotted dolphin (Stenella attenuata), Clymene dolphin (Stenella
clymene) and spinner dolphins (Stenella longirostris) are found in warm (N25 °C) and deep waters (≥1000 m).
High environmental suitability for Atlantic spotted dolphin (Stenella frontalis) seems to occur between 20.5°S
and 30°S in the southeastern Brazilian coastal waters. The projected maps of species distributions showed patterns
closely related to environmental changes at a fine spatial scale and added valuable information about the
offshore limits of those oceanic species. The results suggest that the different species of Stenella have distinct environmental
requirements in the southwestern Atlantic Ocean.
We describe a fossil odontocete periotic from the Nagasakihana, Cyoshi, Chiba Prefecture Japan. The specimen was found as a pebble on the beach and no matrix was preserved. At the area from which the specimen was found, there are... more
We describe a fossil odontocete periotic from the Nagasakihana, Cyoshi, Chiba Prefecture Japan. The specimen was found as a pebble on the beach and no matrix was preserved. At the area from which the specimen was found, there are conglomerates representing the lowest part of the Naarai Formation （corresponding to planktonic foraminiferal zone PL1: latest Miocene-early Pliocene） and many fossils have been recovered from the Naarai Formation. But, at the same area, Kato （2017） reported several fossils from the unnamed Holocene deposit which is exposed a few meters below the coastal line. Therefore, the age of the present specimen remains unclear （possibly latest Miocene-early Pliocene or Holocene）. The periotic displays a combination of the following morphological characters and diagnosed as genus Neophocaena: anterior bullar facet is not present; parabullary ridge is present but not so laterally developed as typically seen in the Delphinidae; outline of anterior process is quadrangular in lateral view; anterior process is directed slight medially; aperture for vestibular aqueduct opens dorsally as slit; dorsal tuberosity is not so developed; foramen sigulare is separated by spiral cribriform tract by high crest; periotic body is relatively narrow in comparison with the width of pars cochlearis. Since the present specimen has a much wider transverse crest in comparison with that of N. phocaenoides, here we report the present specimen as Neophocaena sp.