Early Mode of Life and Hatchling Size in Cephalopod Molluscs: Influence on the Species Distributional Ranges.
Cephalopods (nautiluses, cuttlefishes, squids and octopuses) exhibit direct development and display two major developmental modes: planktonic and benthic. Planktonic hatchlings are small and go through some degree of morphological changes during the planktonic phase, which can last from days to months, with ocean currents enhancing their dispersal capacity. Benthic hatchlings are usually large, miniature-like adults and have comparatively reduced dispersal potential. We examined the relationship between early developmental mode, hatchling size and species latitudinal distribution range of 110 species hatched in the laboratory, which represent 13% of the total number of live cephalopod species described to date. Results showed that species with planktonic hatchlings reach broader distributional ranges in comparison with species with benthic hatchlings. In addition, squids and octopods follow an inverse relationship between hatchling size and species latitudinal distribution. In both groups, species with smaller hatchlings have broader latitudinal distribution ranges. Thus, squid and octopod species with larger hatchlings have latitudinal distributions of comparatively minor extension. This pattern also emerges when all species are grouped by genus (n = 41), but was not detected for cuttlefishes, a group composed mainly of species with large and benthic hatchlings. However, when hatchling size was compared to adult size, it was observed that the smaller the hatchlings, the broader the latitudinal distributional range of the species for cuttlefishes, squids and octopuses. This was also valid for all cephalopod species with benthic hatchlings pooled together. Hatchling size and associated developmental mode and dispersal potential seem to be main influential factors in determining the distributional range of cephalopods.
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta, Barcelona, Spain.
Roger
http://orcid.org/0000-0001-8122-3449
R
Villanueva
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta, Barcelona, Spain.|Centro de Estudos do Mar, Universidade Federal do Paraná (UFPR), Pontal do Paraná, Brazil.
Erica A G
EA
Vidal
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta, Barcelona, Spain.
Fernando Á
FÁ
Fernández-Álvarez
Excellence Centre for Biodiversity of Peninsular Thailand (CBIPT), Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, Thailand.
Jaruwat
J
Nabhitabhata
D063147:Animal Distribution; D000818:Animals; D049830:Cephalopoda / Q000145:classification / Q000254:growth & development*; D052284:Clutch Size; D005260:Female; D008018:Life Cycle Stages; D008297:Male; D012098:Reproduction; D013045:Species Specificity; D013997:Time Factors