Tenellia puellula (Baba, 1955) [Cratena]

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Tenellia puellula has a translucent pink body with a large opaque white patch between the first pair of cerata and the oral tentacles, including the base of the rhinophores. The cerata have white longitudinal lines. The smooth rhinophores are basally opaque white, then translucent orange, the apex is opaque white. The oral tentacles are basal translucent, then white. There is a distinctive orange line on and between the oral tentacles. The posterior end of the foot is white.
Baba described Cratena puellula on a single 10 mm specimen, a modified copy of the painting accompanying his description is here, it shows an orange V-shaped mark on the dorsal surface between the first pair of cerata, the open half is black/brown. The digestive glands in the cerata are series of black/brown spots, there are thin white longitudinal lines on the cerata, and there is a single orange spot about a third the way down from the tip.
There are only a few pictures of this species online, from Japan, also Japan, and from the Sunshine Coast, Queensland, Australia. Those pictures show that Tenellia puellula seems to be very variable. Some specimens lack the large white patch between the first pair of cerata and the oral tentacles, in some specimens is the orange spot on the cerata faint or even absent. In most specimens are the digestive glands tan/brown. The most reliable characters for defining Tenellia puellula are the transverse orange stripe between the oral tentacles, and the longitudinal white lines on the cerata. This specimen is the closest match to Baba’s original painting.
Pretty similar with thin white longitudinal lines on the cerata is
Tenellia sp. 24 which differs by the uniformly milky-white body colour, by the distinctive orange patch on the head, by the colour ot the rhinophores, which are basally translucent orange, the outer half is frosted opaque white, and it lacks the orange line on and between the oral tentacles, and lacks also the large opaque white patch.
This species was posted on 4 July 2011 at these websites as Trinchesia sp. J  Genus: von Ihering, 1879, and changed on 15 July 2011 into
Trinchesia sp. 10  Genus: von Ihering, 1879. I identified it on 13 July 2017
For some genera, such as Trinchesia was the alphabet almost through. I had to change the distinguishing alphabetic character into a number. I had chosen 2-digit numbers, even though '01' looks a little bit stupid, and now is only the genus italic written.
Cella et al. (2016) restricted the genus Cuthona  Alder & Hancock, 1855 to the type species, C. nana (Alder & Hancock, 1842) just like Miller (2004) did, and synonymised the genera
- Catriona  Winckworth, 1941,
- Phestilla  Bergh, 1874,
- Cuthona  Alder & Hancock, 1855 (partim), and
- Trinchesia  Ihering, 1879
with Tenellia  A. Costa, 1866 in the Family Fionidae  J.E. Gray, 1857.
I moved on 25 December 2016 Trinchesia sp. 10  Genus: von Ihering, 1879 to the Genus Tenellia  A. Costa, 1866.
Miller, M.C. 2004. An appraisal of the identity of the New Zealand species of the aeolid nudibranch family Tergipedidae (Gastropoda: Opisthobranchia). Journal of Natural History 38: 1183-1192.
Kristen Cella, Leila Carmona, Irina Ekimova, Anton Chichvarkhin, Dimitry Schepetov & Terrence M. Gosliner (2016)
A Radical Solution: The Phylogeny of the Nudibranch Family Fionidae.
PLoS ONE 11(12): e0167800. doi:10.137 1/journal .pone.0167800
The above publication is completely online, open access, CC-license
Baba, K. (1955) Opisthobranchia of Sagami Bay, Supplement.
Iwanami Shoten: Tokyo. 59pp., 20 Plates
How to cite:
Köhler, E. (2017), published 13 July 2017, Tenellia puellula (Baba, 1955)
available from https://www.Philippine-Sea-Slugs.com/Nudibranchia/Dexiarchia/Tenellia_puellula.htm