AMPHIURIDAE Ljungman, 1867

Alitto, Renata A. S., Bueno, Maristela L., Guilherme, Pablo D. B., Domenico, Maikon Di, Christensen, Ana Beardsley & Borges, Michela, 2018, Shallow-water brittle stars (Echinodermata: Ophiuroidea) from Araçá Bay (Southeastern Brazil), with spatial distribution considerations, Zootaxa 4405 (1), pp. 1-66 : 23-24

Family AMPHIURIDAE Ljungman, 1867

Type taxon. Amphiura Forbes, 1843 .

Diagnosis. Disc usually with many scales. Radial shields prominent, half-circle shape. One pair of infradental papillae on the apex of the jaw. Slender arms bearing short, erect and frequently smooth spines. None, one, or two tentacle scales. Muted color patterns. The family is primarily characterized by the oral frame ( Ljungman 1866; Thomas 1962; Clark 1970; Tommasi 1970; Hendler et al. 1995; Borges & Amaral 2005).

Comments. Amphiuridae is the most diverse family among the Ophiuroidea ( Stöhr et al. 2012a). This large taxon perhaps should be divided into several families. However, it will require a great sampling effort to understand its internal relationships ( O’Hara et al. 2017). The high diversity is related to its success in establishing an extended bathymetric range and adapting to a wide variety of environments (e.g., soft bottoms, rocky shores, and biological substrates) ( Borges & Amaral 2005; Barboza & Borges 2012). Some species voluntarily autotomize the disc during reproduction to aid with the dispersal of gametes ( Amphiodia pulchella , Microphiopholis atra , and Microphiopholis subtilis ( Manso et al. 2008)) . M. gracillima also autotomizes it when disturbed and during sublethal predation events ( Stancyk et al. 1994). They regenerate the disc, however, complicating species identification as a regenerating disc may appear different from an uninjured one ( Tommasi 1970; Hendler et al.

1995). Amphiuridae comprises 506 species distributed across 27 genera ( O’Hara et al. 2017). In Brazil, 48 species belonging to 11 genera are recorded ( Barboza & Borges 2012).