Evolution of Morphological and Behavioral Ontogenies in Females of a Highly Dimorphic Clade of Blennioid Fishes

Abstract

Abstract.Comparison of ontogenetic trajectories with those inferred for ancestors provides a powerful but underused tool for the study of the evolution of different types of phenotypic characters. This approach was used to study morphological and behavioral evolution of the highly dimorphic chaenopsid genus Coralliozetus (Teleostei: Blennioidei). All sexually dimorphic synapomorphies of Coralliozetus involved evolution in females only; one character evolved via terminal addition (peramorphosis), whereas six evolved via terminal deletion (paedomorphosis). Evolution of the ontogeny of two behavioral characters (microhabitat use and feeding rate), as inferred by focal animal observations of eight species of tube blennies, was also confined to females and conformed to terminal deletion. Both sexes of outgroups and males of all species of Coralliozetus exhibit an ontogenetic shift from the open as juveniles to shelters as adults. However, females of all species of Coralliozetus retain the juvenile behavior of residing in the open. Blennies residing in the open take significantly more feeding bites than conspecifics residing in shelters, consequently, female Coralliozetus retain the high feeding rate of juveniles. Several of the paedomorphic morphological features of Coralliozetus females are plausibly associated with their paedomorphosis in microhabitat use. These include their reduced conspicuousness and reduced robustness compared to conspecific males. In groups such as chaenopsids, which undergo significant ontogenetic changes in microhabitat, paedomorphosis provides a mechanism for rapid coevolution of behavior and morphology. This study, the first to document the evolution of sexual dimorphism via both behavioral and morphological paedomorphosis, demonstrates the unique insights to be gained from a multidimensional analysis of phenotypic evolution.

Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

“…The profundal PB-morph seems to retain these juvenile traits into adulthood. Such developmental restrictions are defined as paedomorphism and are well known from many fish taxa (Winterbottom 1990; Hastings 2002), including a few cases of small-sized Arctic charr morphs (Balon 1980; Jonsson et al. 1988; Skúlason et al.…”

Nuclear and Mitochondrial Sequence Data Reveal and Conceal Different Demographic Histories and Population Genetic Processes in Caribbean Reef Fishes

“…The two species are closely related (Hastings 1990 and Eytan et al, unpubl. data), share the same mating system (male resource defense polygyny; Hastings 2002), pelagic larval duration (21–24 days; Johnson and Brothers 1989), and ecologically overlap (Clarke 1994). The two species differ in microhabitat use, though.…”

Ontogeny of microhabitat use and two-step recruitment in a specialist reef fish, the Browncheek Blenny (Chaenopsidae)

“…However, the recruitment pathway of Browncheek Blennies is unique in that it seems to be operating in the reverse of the welldescribed pattern of refuge seeking by juveniles (Shulman 1985;Hixon and Jones 2005). This pattern reflects the importance of (and dependence on) shelters for adult reproductive success in chaenopsids, not just as a means of escape from predation (Hastings 1988(Hastings , 2002.…”

“…Furthermore, the significant decline in feeding rate associated with moving to a shelter could have implications for Browncheek Blenny success, through a sacrifice of maintenance, growth, and reproduction. The typical ontogenetic trajectory of chaenopsids, however, provides an opportunity for release from these constraints via retention of juvenile behaviors (dwelling in the open where feeding rates are higher) and features (cryptic coloration) as documented for females of the genus Coralliozetus (Hastings 2002). Males of these chaenopsids are constrained to make the ontogenetic transition to occupy the specialized microhabitat of shelters because these are sites of egg deposition and defense (Hastings 1986).…”