Previously some authors synonymised Antiopella with Janolus and assigned the genus Janolus to the Janolidae family (see ITIS.gov[4] or AnimalDiversity[5]), others (see Seaslug Forum[6]) to the family of Zephyrinidae, and these were synonymised names of Proctonotidae (see WoRMS).[7] In 2019 an integrated taxonomic study reinstated Antiopella and Janolus as separate genera and placed them in the family Janolidae.[8]
Description
This species is semi-transparent and has an oval-shaped outline. It is cream or light brown in colour, and grows to approximately 7.5 cm in length. The head has oral tentacles that are short.[9]
The lateral cerata are numerous, have a smooth surface and an inflated appearance. The central digestive gland lobe is thin and brown in colour and can be seen through each ceras. These gland lobes divide at the tip of the cerata into numerous terminal branches, distinguishing Janolids from Aeolid nudibranchs. The tips of the cerata are bluish-white and iridescent.[10]
The white surface colouration that is present on the cerata also appears in patches or lines along the bare central dorsum, as well as around the lamellate rhinophores and on the metapodium. The rhinophores are joined together at their bases with a swollen and wrinkled accessory caruncle. Both the rhinophores and median sensory caruncle are somewhat darker in colour than the rest of the body.[9]
The spawn of this species appear as a light pink or white string forming a wavy, circular pattern. The eggs themselves are contained within packets with transparent patches in between. This gives them the appearance of beads.[10]
^Thomas E. Thompson et G.H. Brown, Biology of Opisthobranch Molluscs : The standard work on British nudibranchs, with up to date information and colour paintings of nearly all species, vol. 2, Ray Society, 1984 (ISBN0903874180)
^Thomas E. Thompson, Molluscs: Benthic opisthobranchs, Leiden, Brill, coll. « Synopses of the British Fauna » (no 8), 1988 (ISBN9004084398)
^R. Cattaneo-Vietti, R. Chemello et R. Gianuzzi-Savelli, Atlas of Mediterranean nudibranchs, Roma, Editrice La Conchiglia, 1990, 264 p. (OCLC 26035712, LCCN 93155161)
^Egidio Trainito, Nudibranchi del Mediterraneo. Guida al riconoscimento dei molluschi opistobranchi, 2005ª ed., Milano, Il Castello, 2005, ISBN88-8039-438-X.