Chondrichthyan egg cases from the southwestern Atlantic

MABRAGAÑA, E.; FIGUEROA, D. E.; SCENNA, L. B.; DÍAZ DE ASTARLOA, J. M.; COLONELLO, J.; MASSA, A.

New Orleans (USA)

Congreso; 2006 Joint meeting of the American Society of Ichthyologists and Herpetologists; 2006

Egg cases of 16 species of oviparous chondrichthyans from the southwestern Atlantic were described and compared. Samples (n= 130) were obtained from females containing egg cases in their uteri and egg cases found in benthic samples, collected during research cruises carried out by the Instituto Nacional de Investigación y Desarrollo Pesquero on the Argentinean continental shelf (34 °-55 ° S) and from captivity specimens in Museo del Mar. Eight morphometric characteristics were measured following traditional methodology and two more were added, keel thickness (KT) and straight distance from anterior apron margin to curvature of anterior horn. The speciose genus Psammobatis, whose ECL (egg case length without horns) ranged 25-53 mm, presented a great variety of egg cases features and showed the smallest ECL. Those of the endemic genus whose ECL (egg case length without horns) ranged 25-53 mm, presented a great variety of egg cases features and showed the smallest ECL. Those of the endemic genus Psammobatis, whose ECL (egg case length without horns) ranged 25-53 mm, presented a great variety of egg cases features and showed the smallest ECL. Those of the endemic genus Sympterygia (ECL range: 51-68 mm) presented the highest KT and the longest posterior horns. Egg cases of Rioraja agassizi (EC range: 61-68 mm) had relative straight sides. Egg cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus horns. Egg cases of Rioraja agassizi (EC range: 61-68 mm) had relative straight sides. Egg cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus (ECL range: 51-68 mm) presented the highest KT and the longest posterior horns. Egg cases of Rioraja agassizi (EC range: 61-68 mm) had relative straight sides. Egg cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus Rioraja agassizi (EC range: 61-68 mm) had relative straight sides. Egg cases of the genus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus Bathyraja (ECL range: 75-98 mm) were characterized by a conservative morphology, rough surface case and curved horns. Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus Dipturus Atlantoraja castelnaui presented a large egg case with a wide lateral keel (ECL range: 97-104 mm). The genus DipturusDipturus (ECL range: 115-230 mm) showed the largest ECL and very developed posterior apron. The unique oviparous shark that occurs in Argentinean waters, Schroederichthys bivius , had a cigar-shaped egg case with curled tendrils on posterior tip. Egg cases of the elephant fish, Callorhynchus callorhynchus , were spindle-shaped with anterior and posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf. posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf. had a cigar-shaped egg case with curled tendrils on posterior tip. Egg cases of the elephant fish, Callorhynchus callorhynchus , were spindle-shaped with anterior and posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf. posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf. Schroederichthys bivius , had a cigar-shaped egg case with curled tendrils on posterior tip. Egg cases of the elephant fish, Callorhynchus callorhynchus , were spindle-shaped with anterior and posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf. posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf. Callorhynchus callorhynchus , were spindle-shaped with anterior and posterior tubular extensions. Chondricthyans egg cases can be a useful tool for identifying individual species and egg laying areas, therefore a provisional key to the southwestern Atlantic chondricthyans egg cases was constructed. Some results presented in this abstract are part of an ongoing study about ecology, biology and biodiversity of species of Bathyraja on the Argentinean continental shelf.Bathyraja on the Argentinean continental shelf.