Facelinidae (Bergh, 1889)

Broms, Fredrik, 2024, Diversity of nudibranchs in shallow water habitats in the region of Tromsø, northern Norway, Fauna norvegica 43, pp. 84-109 : 97

Family Facelinidae (Bergh, 1889)

Facelina auriculata (Müller, 1776) Figure 4C

Material examined: One specimen, KVA, 14 November 2021, 15 mm, FB, NUIT-1031 ; One specimen, HIL, 12 February 2022, 15 mm, FB, NUIT-1127 ; One specimen, HIL, 12 June 2022, 30 mm, FB, NTNU-VM-85680/NUIT-1175 ( Figure 4C ) ; One specimen, SKI, 06 August 2022, 28 mm, FB, NTNU-VM-85699/NUIT-1200 .

Localities: HIL, KFS, KVA, SFJ, SGU, SKI, THA, TPR

Distribution and remarks: Facelina auriculata has previously been recorded from most of the Norwegian coast ( Evertsen & Bakken 2005) but not from Russian waters. In this study, F. auriculata was a commonly encountered species. It was found all year round both in the intertidal and at fouling communities. Spawning was mainly observed in July and juveniles were predominantly found in November - December. The present records are, however, the first documented records from the Tromsø region.

Facelina bostoniensis (Couthouy, 1838) Figure 4D

Material examined: Four specimens, HIL, 18 October 2020, FB, photographic record ( Figure 4D ) ; One specimen, HIL, 03 December 2022, 22 mm, FB, NTNU-VM-85712/NUIT-1255 .

Localities: HIL, KFS, TVK

Distribution and remarks: Facelina bostoniensis has previously been recorded north to Nordland ( Evertsen & Bakken 2005) with a few recent unverified observations as far north as Troms ( Artskart 2024). In the present study, animals were found associated with Ectopleura larynx Ellis & Solander, 1786 at fouling communities. All records were made during autumn – winter. The present records are the first documented records of the species from the Tromsø region.

Favorinus branchialis (Rathke, 1806) Figure 4E

Material examined: One specimen, HIL, 18 October 2020 , FB, photographic record ( Figure 4E ); Three specimens, KVA, 14 November 2021 , 7, 10, 5 mm, FB, NTNU-VM-85706/NUIT-1028, NTNU-VM-85721/NUIT-1029, NUIT-1030; One specimen, HIL, 10 April 2022 , 9 mm, FB, NTNU-VM-85662/NUIT-1154; One specimen, HIL, 12 June 2022 , 14 mm, FB, NUIT-1172; One specimen, HIL , 14

November 2023, 7 mm, FB, NUIT-1341.

Localities: EKJ, HIL, KFS, KVA, TVK, UTE

Distribution and remarks: Favorinus branchialis has been reported from most of the Norwegian coast north to Nordland ( Evertsen & Bakken 2005; Moen & Svensen 2020). Old records from Russian waters were later removed due to misidentifications ( Martynov et al. 2006). In the present study, F. branchialis was found to be a fairly common nudibranch occurring all year round. Specimens were found mainly during autumn in association with eggs by Onchidoris muricata and Polycera spp. on Saccharina latissima . The present records are the first records from the Tromsø region and the northernmost known observations of the species.

Figures

Figure 4. A. Aeolidia papillosa, NUIT-1257, B. Aeolidiella glauca, NUIT-1309, C. Facelina auriculata, NTNU VM-85680/NUIT-1175, D. Facelina bostoniensis, photo record, 18 October 2020, E. Favorinus branchialis, photo record, 18 October 2020, F. Coryphella browni, NTNU VM-84427/NUIT- 1104, G. Coryphella chriskaugei, NUIT-1233, H. Coryphella gracilis, NTNU VM-85715/NUIT-1066, I. Coryphella lineata, NUIT-1232, J. Coryphella cf. monicae, NUIT-1275, K. Coryphella cf. orjani, NTNU VM-85713/NUIT-1124, L. Coryphella verrucosa, rufibranchialis form, NTNU VM-85655/ NUIT-1263. Scale bar: 10 mm. All photos: Fredrik Broms.