Description of two species of Caprella (Crustacea: Amphipoda: Caprellidae) from the North Pacific; C. californica Stimpson, 1857 and C. scauroides Mayer, 1903, with a new appraisal of species ranking for C. scauroides

The spreading of the non-native caprellid (Crustacea: Amphipoda) Caprella scaura Templeton, 1836 into southern Europe and northern Africa: a complicated taxonomic history.

“…4, Table 2), could correspond to different valid species, as has already happened with other "forms" described by Mayer (i.e. Cabezas et al, 2013;Takeuchi & Oyamada, 2012). The form "typica" has also been reported as the variety introduced along the east and west coast of North America (Marelli, 1981;Foster et al, 2004) and Hawaii (Edmonson & Mansfield, 1948).…”

“…About 50 years later, Mayer (1890Mayer ( , 1903 recognized 6 "formae" (= varieties): C. scaura f. typica (1890), including the specimens described by Templeton and others found in Brazil and Australia, C. s. f. diceros (1890) from Japan, C. s. f. cornuta (1890) from Chile and Brazil, C. s. f. spinirostris 1890from Chile, C. s. f. californica (1903) from California and C. s. f. scauroides (1903) from Hong Kong and Japan. According to recent rules of nomenclature, these varieties are now treated as subspecies (Krapp et al, 2006;Takeuchi & Oyamada, 2012). Mayer (1903) grouped these subspecies in two separate groups, one for specimens without a ventral spine between the insertions of gnathopods 2, including C. s. typica, C. s. diceros and C. s. cornuta, and the other group for specimens with a ventral spine between the gnathopods 2, including the remaining specimens.…”

“…Dougherty & Steinberg (1953) separated C. s. californica as a distinct species and re-established Stimpson's (1857) name C. californica andMcCain &Steinberg (1970) synonymized the other two subspecies with ventral spine, C. s. scauroides and C. s. spinirostris, with C. californica [sensu lato]. Recently, Takeuchi & Oyamada (2012) proposed C. s. scauroides to a species level based on differences with C. californica [sensu stricto] from California. In summary, at the present time, three valid species have been recognized: C. scaura, C. californica and C. scauroides.…”

A new species of <i>Caprella</i> (Crustacea: Amphipoda: Caprellidae) from the landward slope of the Japan Trench

“…To date, 183 species of this genus have been registered in the World Register of Marine Species (WoRMS) (Horton et al 2018). Japan and adjacent areas have the highest species diversity of caprellids in the world (McCain & Steinberg 1970;Takeuchi 1999), and ∼75 species from this genus have been recorded to date (Mori 1999;Takeuchi 1999;Guerra-Garcia & García-Gómez 2003;Aoki & Ito 2012;Takeuchi & Oyamada 2013). Most Caprella spp.…”

A taxonomic study on the Phtisicidae (Crustacea: Amphipoda) of New South Wales, Australia

“…Hence, we do not include the records of M. novaehollandiae in the tropical region of the Indo-Pacific ( (Mayer 1903;Laubitz 1991, Guerra-García 2002, 2003, 2004a, 2004b, 2006Guerra-García and Lowry 2009) in the synomym list. Recently, Takeuchi and Oyamada (2013) studied in detail Caprella californica Stimpson, 1857 [sensu lato] which is widely distributed on both sides of the North Pacific as a common species, and reported that the differences of Japanese C. californica [sensu lato] from California ones are at species level. In their opinion the Japanese species identified as C. californica [sensu lato] is actually Caprella scauroides Mayer, 1903. Genus Notoprotomima gen. nov.…”