Larval Growth and Development
As highlighted in the Reproductive Biology section of this website, Turbo perspeciosus are thought to undergo planktonic larval development. In a study conducted by Strathmann (1978) it was noted that of all the superorder Vetigastropoda (under which T. perspeciosus falls) studied, not a single species with planktonic development were capable of opposed band-cillary feeding as a veliger larvae. This finding, confirmed in biological studies, reveal that the larvae of superfamily Trochoidea undergo a short and rapid embryonic and larval development phase, which is completed within a few days of them initially entering the plankton (Meyer et al. 2005).
No studies which have been conducted to date investigate the larval growth and development of T. perspeciosus (Scaley Turban), however comprehensive research has been done on a closely related Turban species Turbo argyrostomus. Currently, the larval growth and development patterns of this species give the best indication of the larval development patterns of the Scaley Turban.
Accordingly, based on the T. argyrostomus patterns, after successful fertilisation has occurred, the embryo undergoes its first cleavage after just 30 minutes, with cleavages into 4, and then 8 macromere cells following, however with increasing duration between cleaves (Kimani 1996). Gastrulation (the movement of these cleaved cells inwards) occurs between 5 and 6 hours following fertilisation. Larvae hatch prior to undergoing torsion (a trait common among all gastropods – see internal anatomy) after only 14-18 hours after fertilisation occurs. During the final larval stage, individuals are referred to as veligers, and at this stage are green in colour, possessing 2 eye spots and the ability to swim. Amazingly, the muscular, sticky foot characteristic of Turbanid snails is present just 2 days following fertilisation (Kimani 1996).
Newly settled veliger larvae display a transparent, spherical shell with irregular ornamentation, believed to be a characteristic trait of individuals that undergo planktonic larval development. Turbinid shells are composed of multiple whorls, or coils, the first of which is partly developed 2 weeks following metamorphosis. The second whorl is completely developed by month 2 (Kimani 1996). Interestingly, the growth of the shell was found to vary based on the specific algal diet fed to the growing individual. Kimani (1996) found that the diet resulting in the most rapid growth was one consisting of a combination of red and green algae, followed by a strictly red algae diet, and lastly a green algae diet which resulted in a shell growth two times as slow as that of a strictly red algae diet. Shell weight varied too based on diet, with a green algae diet result in the heaviest shell, followed by red and combined respectively.
Interestingly, shell colouration was found to also vary depending on diet, with green algae resulting in shells with a green colouration, whilst red and combination diets lead to pale green shells with mottled colouration and red blotches (Kimani 1996).
  
Figure 1. Photographs demonstrating the wide amount of variation is shell colour possible within Turbo perspeciosus (Centre photo courtesy of Francesco 2011)
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