Ontogenetic Niches and the Development of Body Shape in Juvenile Sea Turtles

Ontogenetic development of the European basal aquatic turtle <i>Pleurosternon bullockii</i> (Paracryptodira, Pleurosternidae)

“…Brinkman et al, 2013;Jansen and Klein, 2014;Szczygielski et al, 2018;Li et al, 2019) and extant turtles (e.g. Somers et al, 2000;Pritchard, 2008;Fish and Stayton, 2014;Pate and Salmon, 2017). The initial distinction among the different ontogenetic stages, "juvenile", "subadult" and "adult", was based on both the size (see Sect.…”

“…Therefore, the fact that the juvenile specimens were found in a different level than the adults probably suggests that they had a different lifestyle than the adults to maintain optimal growth rates. The shift in habitat utilization during the life cycles is widely known for many extant freshwater and marine turtle species (Snover, 2002;Myers et al, 2007;Castellano et al, 2008;Paterson et al, 2014;Pate and Salmon, 2017). It has been suggested that specific habitats can have a strong influence on the survival of the immature stage of some turtle species due to favourable environmental conditions, protection from predators or food availability (Snover, 2002;Paterson et al, 2014).…”

Biphasic allometric growth in juvenile green turtles Chelonia mydas

“…An initial widening during early growth has also been documented in 4 other marine turtle species: loggerheads Caretta caretta and Kemp's ridley Lepidochelys kempii (Salmon et al 2015); flatbacks Natator depressus (Salmon et al 2016); leatherbacks Dermochelys coriacea (Pate & Salmon 2017). How-ever, all these measurements stemmed from laboratory-reared turtles.…”

“…For example, carapace widening occurs in all sea turtle species, except the hawksbill Eretmochelys imbricata, which has a narrower body that may fit more easily under reef ledges or into reef crevasses (Salmon et al 2018). Carapace widening is weakly (but significantly) developed in leatherbacks (Pate & Salmon 2017) and is more pronounced in young flatbacks than in young green turtles (Salmon et al 2016). It is most strongly expressed in juvenile Kemp's ridley turtles that, from an early age, possess shells that are as wide as they are long (Salmon et al 2015), a condition that uniquely persists even in adults (Pritchard 2007).…”

“…Avoiding detection through behavior is also a common functional trait, because small sea turtles are defenseless during the earliest stages of growth (Heithaus 2013). Once again, expression varies and falls into 3 categories: hiding in flotsam (hawksbills, log-gerheads, Kemp's ridleys, green turtles;Carr 1986Carr , 1987, hiding in turbid water (flatbacks; Salmon et al 2016), and ignoring predators (leatherbacks; Salmon et al 2004, Pate & Salmon 2017see Fig. 5), with the last category the least studied or understood.…”