Diversification of the pectoral fin shape in damselfishes (Perciformes, Pomacentridae) of the Eastern Pacific

Abstract

Fin shape strongly influences performance of locomotion across all swimming styles. In this study, we focused on the diversity of the pectoral fin morphology in damselfishes of the Eastern Pacific. Underwater observations and a review of literature allowed the characterization of ten behavioral groups. Territorial and non-territorial species were discriminated easily with traditional morphometrics. Five ecomorphological groups were recognized by geometric morphometric analyses. Geometric data segregated the outgroup from the damselfishes and allowed the distinction of mean morphologies from extreme ones within territorial and non-territorial species. Additionally, geometric morphometric data split Abudefduf into two groups: (1) A. troschelii is similar to C. atrilobata and (2) A. concolor and A. declivifrons are close to Stegastes. Solitary territorial species (e.g., Stegastes) show rounded and high fins whereas non-territorial species living in groups (e.g., Chromis) present long and curved pectoral fins. In the range of morphological variation, the morphologies of Microspathodon (elongate with highly curved hydrodynamic trailing edge) and Azurina (long, slender and angular) represent the extreme morphologies within territorial and non-territorial species, respectively. Our study revealed a strong relationship between the pectoral fin shape and the behavioral diversification in damselfishes.

Morphological Differentiation in the Damselfish Abudefduf saxatilis Along the Mexican Atlantic Coast is Associated with Environmental Factors and High Connectivity

“…The lower APFA (c.a. 50°) observed in individuals of MCRS translates in flapping fin movements (characteristics opposite to rowing), that decrease resistance to water, offer force, and produce a more efficient displacement in environments with fast water flow (Lauder and Jayne 1996;Aguilar-Medrano et al 2013). In accordance with APFA, the remarkable increase in size of the caudal peduncle from TRS to MCRS could be accompanied with an increase of caudal muscle mass (McLaughlin and Grant 1994;Imre et al 2002), and/or of the number and size of muscle fibers in the caudal region (Sfakianakis et al 2011), all of which could provide biomechanical advantages in high-speed reef systems.…”

“…Reefs and marine regions are indicated along the X-axis and black vertical lines separate individuals from different reefs. Abbreviations correspond to those in Table 1 (Color figure online) Evol Biol (Aguilar-Medrano et al 2013;Fulton et al 2013;Binning et al 2014).…”

“…According to our hypotheses and based on previous studies (e.g. Booth and Hixon 1999;Aguilar-Medrano et al 2013;Fulton et al 2013) we selected environmental variables that are known to affect fish morphology: (1) superficial water temperature (°C); (2) water chlorophyll-a concentration (mg/m 3 ) as estimator of primary productivity; and (3) geostrophic velocity (cm/s) as a measure of sea-surface flow. Details on the environmental variables can be found in the Electronic Supplementary Material.…”

“…angle of pectoral fin attachment, APFA) affect movement, posture and maneuverability of individuals. Such modifications may provide biomechanical advantages in reef systems with highspeed water flow (Lauder and Jayne 1996;Aguilar-Medrano et al 2013). Additional biomechanical advantages in highspeed currents may be provided by an increase of the muscle mass in the caudal area (i.e.…”

Storm-induced changes in environmental conditions are correlated with shifts in temperate reef fish abundance and diversity

“…Permanently territorial damselfish (such as P. mccullochi) also have the morphological characteristics to be more manoeuvrable than schooling pomacentrids such as Chromis spp. (Aguilar-Medrano et al, 2013) so may be more capable of functioning during storm events than some other species. Temperature was observed to be a driving factor in the number of individual fish recorded in the assemblage.…”