A secondary nursery area for the copper shark Carcharhinus brachyurus from the late Miocene of Peru. (October 2017)

• Record Type: Journal Article
• Authors: Landini, Walter; Collareta, Alberto; Pesci, Fabio; Di Celma, Claudio; Urbina, Mario; Bianucci, Giovanni
• Is Part Of: Journal of South American earth sciences. Volume 78(2017:Oct.)
• Page Start: 164
• Page End: 174
• Publication Date: 2017-10
• Subjects: Carcharhinidae -- Cerro Colorado -- Ecospace utilization -- Paleoecology -- Pisco Formation -- Tortonian; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2017.07.003
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: The life history strategies of sharks often include the use of protected nursery areas by young-of-the-year and juveniles. Nursery areas can be primary (i.e., grounds where the sharks are born and spend the very first part of their lives) or secondary (i.e., grounds inhabited by slightly older but not yet mature individuals). Criteria utilized to recognize these strategic habitats include: high concentration of young sharks, high food availability, and low predation risk. Since the fossil record of sharks consists mainly of isolated teeth, identification of paleonurseries involves a series of problems due to difficult application of actualistic criteria. A rich shark tooth-bearing level (ST-low1) has recently been discovered in the upper Miocene deposits of the Pisco Formation exposed at Cerro Colorado (southern coast of Peru). Most of the teeth collected from this level belong to the extant copper shark Carcharhinus brachyurus . These teeth are small and compatible with those of extant juveniles. This observation, coupled with other paleoenvironmental considerations, indicates that the ST-low1 horizon could have represented a nursery ground for juvenile individuals of C. brachyurus . The absence of very small-sized teeth (i.e., referable to young-of-the-year) suggests a secondary nursery ground inhabited by immature copper sharks. Observations on the tooth size of other Lamniformes, Carcharhiniformes, and Myliobatiformes occurring along with C. brachyurus point to a significantly juvenile structure of this elasmobranch assemblage, thus supporting the hypothesis of a communal use of the Cerro Colorado paleonursery. Highlights: We discuss a Tortonian elasmobranch assemblage from Cerro Colorado (Pisco Fm). This assemblage mainly consists of small (juvenile) teeth of Carcharhinus brachyurus . Cerro Colorado was used as a secondary nursery area by immature copper sharks. This nursery ground was likely shared by other elasmobranchs (e.g., Myliobatis spp.) Cerro Colorado was exploited as a nursery area for a limited period of time.