BOSTRYCAPULUS CALYPTRAEFORMIS (DESHAYES, 1830) Synonymy Calyptraea echinus Broderip, 1834: 39. Broderip, 1835: 203, pl. 29, fig. 1. Isla Lobos, Peru. 3 syntypes BMNH 1975113. Hoagland, 1986: 173–183. Calyptraea hystrix Broderip, 1834: 39. Broderip, 1835: 203, pl. 29, fig. 2., Isla Lobos Peru. 3 syntypes BMNH 1966629. Crepidula aculeata - Parodiz, 1939 [in part]: 695. Hoagland, 1977 [in part]: 364. Bostrycapulus aculeatus - Olsson & Harbison, 1953 [in part]: 280. Simone, 2002 [in part]: 18. Crepidula cf. aculeata - sp. 2. Collin, 2003b: 618– 640. C. cf. aculeata - Panama. Collin, 2003a: 541–593. Original description: ‘C. testâ ovato-rotundatâ, gibbosâ, rufescente, longitudinaliter striatâ; strius rugosis, ad marginem evanescentibus; apice obliquo, spirato’. Type material: two syntypes in the Paris museum (Hoagland, 1983; P. Bouchet 2001 pers. comm.). One is figured in Hoagland (1983). Type locality: Peru (?). Deshayes (1830) supposed that the types came from Peru because they were bought with shells of other Peruvian species. Diagnosis: the shell morphology and anatomy of B. calyptraeformis do not differ from those of B. aculeatus as described above. B. calytraeformis can be distinguished from the other species of Bostrycapulus by the presence of planktotrophic development and a smooth protoconch with 1.5 whorls (Fig. 5). Diagnostic DNA sequence differences distinguishing B. calyptraeformis from all other Bostrycapulus species are in the following positions in the COI sequences submitted to GenBank (position 1 = position 1537 of the D. yakuba mitochondrial genome, GenBank # X03240): 39 (g), 42 (c), 57 (g), 69 (a), 75 (c), 171 (c), 259 (t), 282 (g), 321 (a), 354 (g), 387 (c), 402 (c), 441 (c), 462 (g), 486 (c), 582 (c). Distribution: northern Peru to the Pacific coast of eastern Panama and the Perlas Islands but not extending into the Gulf of Chiriqui. This species also occurs in Hawaii where it is probably introduced and it may have been recently introduced into Guam. This species can reach densities of greater than 1000 individuals per square meter in the intertidal zone of Panama (unpubl. data) and occurs to depths of at least 50 m. Description: shell morphology and anatomy of this species differ from B. aculeatus only in protoconch morphology (Fig. 5B, E). Development is planktotrophic. Animals from Panama produce small 180 Mm eggs (Hoagland, 1986) and hatch at a length of 345 Mm (Collin, 2003c). At hatching, the larval shell is covered with fine spines or periostracal hairs that are visible under a compound microscope. Animals from Hawaii hatch at 320 Mm (Bell, 1993). The veliger larvae have a black intestine, and two small red stripes in the food groove along the anteriolateral and posteriolateral corners of the velum (Fig. 8B). There are no pigment spots on the foot or velum. Larvae from Panama settle in culture starting at a shell length of 700– 800 Mm (pers. observ.; Collin, 2003c). Animals from northern Peru (Mancora, Zorritos, and Paita) also have planktotrophic development, but more detailed observations are not available. This is the only known species of Bostrycapulus with planktonic larvae. Notes: the type of this species is from Peru and the description presented here is based on material from the north coast of mainland Peru, supplemented with observations of material from Panama and Hawaii. As diagnostic material from Isla Lobos is not currently available, the synonymy of C. calyptraeformis with C. echinus and C. hysterix has yet to be rigorously demonstrated. The genetic differentiation between the samples from Peru, and Panama and Hawaii is almost as great as the differentiation among other sibling Crepidula species (e.g. Collin, 2000a, 2001) suggesting that these may be two distinct species. Because the available data are insufficient to unambiguously determine the status of these populations and I am aware of no differentiation other than the DNA sequences, I have chosen to conservatively place them all in B. calyptraeformis until more information is available.

Published as part of Collin, Rachel, 2005, Development, phylogeny, and taxonomy of Bostrycapulus (Caenogastropoda: Calyptraeidae), an ancient cryptic radiation, pp. 75-101 in Zoological Journal of the Linnean Society 144 (1) on pages 94-95, DOI: 10.1111/j.1096-3642.2005.00162.x, http://zenodo.org/record/5433494