Cerberilla ambonensis Bergh, 1905

Description

In life the animal was 15 mm long and 5 mm wide; the foot tentacles and oral tentacles are both very long. The colour was light brownish, with a single black dot at the tip of each ceras. The preserved specimen measured 9 mm long, 5 mm wide and 2 mm high, the cerata reaching 4 mm. The colour was overall pale dirty yellowish; the oral tentacles greyish-violet, as were the nape and the anterior part of the back (both also bearing white dots). The same coloration appeared on the upper side of the foot tentacles and the front part of the foot. The upper half of the rhinophores was black; the tips of the cerata were grey, with a blackish-brown spot on the outer side just below each tip — visible also on the smaller cerata.

The body form was rather short. The front of the head was flattened, 2 mm wide, with loose margins. The closely-set rhinophores stood between the first ceratal rows of the two sides. On either side of the broad back rose 11 slightly elevated ceratal pedestals, each carrying a transverse row of firmly-attached cerata (3 in the 1st row, 4 in the 2nd-3rd, 6 in the 4th-5th, 7 in the 6th-9th, 6 in the 10th and 4 small ones in the 11th). The cerata were almost cylindrical, pointed above. The anal papilla lay laterally on the back in front of the 5th pedestal.

Distribution

Type locality: a reef off Ambon, Moluccas, Indonesia, at 36 m depth. The species inhabits sandy and silty-sandy substrates across the tropical Indo-West Pacific.

Etymology

The specific epithet ambonensis is a Latinised toponymic adjective meaning "from Ambon", referring to the type locality.

Remarks

The genus Cerberilla is characterised by long oral tentacles, tentacle-like foot extensions and robust dentition — all associated with a burrowing lifestyle in soft substrata.

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References

• Cerberilla ambonensis Bgh. n. sp., Bergh R. (1905). Die Opisthobranchiata der Siboga-expedition. https://doi.org/10.5962/bhl.title.11223
• アンボンカスミミノウミウシ（新称）, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.