Close-up image of mantle of Jorunna onubensis. Found under a stone at 14 m depth. Cadaqués, Catalonia. October 2007. © M. Pontes.
A: Crowded, match-like, retractile tubercles with subapical ring of sharp projecting spicules (caryophyllidia). Found on both J. tomentosa and J. onubensis. Difficult to photograph because small and transparent-colourless.
The bright white opaque cap on some of them is mentioned in the original description of J. onubensis as ‘iridescente’; no iridescence can be seen in this image, but the camera may not have captured it. The white caps appear to be quite frequent on the caryophyllidia of J. onubensis, but some specimens of J. tomentosa also have some white caps.
Jorunna onubensis Cervera, García-Gómez & García, 1986,
is very similar to J. tomentosa; reliable identification of this species requires examination of dissected anatomical features and, ideally, D.N.A sequencing. The external features below are described in the original description of J. onubensis [based on four intertidal specimens from Huelva, southern Spain]. The features illustrated in this Flickr account are on a specimen from Catalonia of J. onubensis identified by Miquel Pontes and confirmed by Prof. J. Lucas Cervera. Many features are common to both J. onubensis and J. tomentosa; confirmation by dissection and/or D.N.A, sequencing is desirable. Specimens of J. onubensis photographed by one of the authors of its first published description, J. C. García Gómez, can be seen at opistobranquis.info/en/guia/nudibranchia/euctenidiacea/do…
and other images by L. Sánchez-Tocino at
wpd.ugr.es/~litoraldegranada/el-litoral/el-litoral-sumerg…
It has been recorded from Spain, Portugal, Madeira and the Canary Islands.
FULL 9 POINT COMPARISON with J. tomentosa:
Jorunna onubensis
1: 12mm to 18mm long (four specimens March & April 1984). Up to 55mm long (Sánchez-Tocino, accessed February 2018).
2: Light brown, often slightly pinkish 34 Jorunna tomentosa album. Comparison image of Jorunna onubensis [sometimes grey?]. Sometimes with dark, greyish or greyish-brown, blotches of varying size. Small opaque white marks near periphery of mantle 36 Jorunna tomentosa album. Comparative ventral view of Jorunna onubensis.
3: Crowded, match-like, retractile tubercles with skirt of sharp projecting spicules (caryophyllidia), similar to J. tomentosa, some with opaque, bright-white apex [‘il mantello è ricoperto da tubercoli cariofillidei molto
fitti. Questi sono circondati da 6-7 spicole le cui estremità sorpassano generalmente la sommità dei tubercoli. A volte le estremità delle spicole rimangono allo stesso livello dei tubercoli e in altri casi ne rimangono al di sotto. – – – Alcuni dei tubercoli dorsali persentavano il loro apice di colore bianco iridescente’.]
4: The translucent, almost colourless, gills have a fine brown punctuation, hardly distinguishable to the naked eye 38 Jorunna tomentosa (right) and comparison image of Jorunna onubensis. & 39 Jorunna tomentosa album. Comparison image of Jorunna onubensis. . The end of the anal papilla is brown with whitish striations that subdivide it into unequal parts 38 Jorunna tomentosa (right) and comparison image of Jorunna onubensis. .
5: Base of extended gills surrounded by collar-like sheath 39 Jorunna tomentosa album. Comparison image of Jorunna onubensis. which closes over the gills when they are retracted into a pit 35 Jorunna tomentosa album. Comparison image of Jorunna onubensis.
6: Slender tapered oral tentacles, similar to J. tomentosa.
7: Convex body with raised profile, similar to J. tomentosa.
8: Short rhinophores are whitish, sometimes with strip of dark brown subapically. Basal stem transparent. About 15 lamellae form conical distal half.
9: Posterior of foot protrudes slightly when in motion.
Jorunna tomentosa
1: Length up to 30 mm (Neuhaus et al, 2021), 55 mm (Thompson and Brown, 1984), often a similar size to Doris pseudoargus.
2: Dorsally, sandy-brown 01 Jorunna tomentosa. Length 60 mm. Intertidal. Orkney. April 1975. , reddish brown, grey-white, grey-cream, yellow 02 Jorunna tomentosa. , yellow cream 03 Jorunna tomentosa. Length 55mm. Menai Strait, Wales. June 2013. , buff-orange, or white 04 Jorunna tomentosa. West Anglesey, Wales. March 2014.. Small opaque white glandular structures near periphery of mantle 03 Jorunna tomentosa. Length 55mm. Menai Strait, Wales. June 2013. but sometimes not discernible 01 Jorunna tomentosa. Length 60 mm. Intertidal. Orkney. April 1975. . Usually, scattered small dark spots and a few dark blotches in a longitudinal row on each side 05 Jorunna tomentosa. Split, Croatia. November 2012. © J. Prkić . ; sometimes blotches absent, or few and small 11 Jorunna tomentosa. 55mm long. Menai Strait, Wales. June, 2013. and occasionally the small spots are absent.
3: Mantle has crowded, small, match-like, retractile tubercles (caryophyllidia) 08 Jorunna tomentosa. Rhinophores from 34 mm and 55 mm long animals. Menai Strait, Wales. with a ring of sharp projecting spicules surrounding the rounded apex. Body has velvety appearance and soft feel.
4: Large yellow-cream to grey gills around brown anal papilla 02 Jorunna tomentosa. & 04 Jorunna tomentosa. West Anglesey, Wales. March 2014. . Gills are often paler than the mantle and sometimes have dark dots.
5: Base of extended gills surrounded by distinct collar-like sheath 09 Jorunna tomentosa, gills and gill sheath. Lengths of animals 55mm and 43mm. Anglesey, Wales. which closes over the gills when they are retracted into a pit 12 Jorunna tomentosa. Length of animal 43mm. Menai Strait, Wales. February 2014. .
6: Slender tapered oral tentacles 15 Jorunna tomentosa. Animal 55mm long. Menai Strait, Wales. June, 2013. .
7: Convex body with raised profile 07 Jorunna tomentosa. West Anglesey, Wales. March 2014. .
8: Short, stout rhinophores have a translucent whitish, or slightly tinted, basal stem and a conical, lamellated, yellow-cream to grey, distal part bearing red to brown pigment dots/marks 08 Jorunna tomentosa. Rhinophores from 34 mm and 55 mm long animals. Menai Strait, Wales. .
9: Posterior of foot protrudes when in motion 19 Jorunna tomentosa. Length 43mm. Menai Strait, Wales. February 2014. .