Madrella ferruginosa, ALDER & HANCOCK, 1864

Gosliner, Terrence M. & Fahey, Shireen J., 2011, Previously undocumented diversity and abundance of cryptic species: a phylogenetic analysis of Indo-Pacific Arminidae Rafinesque, 1814 (Mollusca: Nudibranchia) with descriptions of 20 new species of Dermatobranchus, Zoological Journal of the Linnean Society 161 (2), pp. 245-356 : 250

MADRELLA FERRUGINOSA ALDER & HANCOCK, 1864

Material examined: CASIZ 115806 , two specimens, 10–12 mm alive, one dissected, Tengan Pier, Ishikawa City, Okinawa, Japan, collected 25.vi.1995 by R. Bolland (3218-D), 12 m depth . CASIZ 121200 , one specimen, 5 mm preserved, dissected, Bigej-Mack Reef, Kwajalein Atoll, J. Johnson, 10.x.1995, 35 m depth . CASIZ 099104 , seven specimens, 3–9 mm alive, Tengan Pier, Ishikawa City, Okinawa, Japan, collected 5.iii.1994 by R. Bolland (3218), 12 m depth .

Geographical distribution: This species is known from India ( Alder & Hancock, 1864), Japan ( Baba, 1949, as M. sanguinea ; present study), South Africa ( Fraser, 2001), the Marshall Islands (present study), and Madagascar (present study).

Buccal armature: The jaws are large and thickly cuticularized with a thick masticatory margin and two to three rows of long, pointed denticles. The radular formula of CASIZ 121200 is 48 ¥ 1.1.1.1.1. The rachidian teeth are claw-shaped with a thick, projecting, pointed central cusp that has six pointed, flanking denticles on each side. The next lateral tooth is also claw-shaped with ten shorter, pointed denticles that decrease in size towards the rachidian tooth. The next lateral tooth is a long pointed hook with no denticles.