The nudibranch Eubranchus farrani Alder and Hancock, 1844 is recorded from the Azores for the first time. The presence of the sacoglossan Placida cremoniana (Trinchese, 1892) in the Azores is confirmed. Pleurobranchus sp. from the Azores, Madeira and the Canary Islands is compared with P. garciagomesi Cervera et al. 1996; it probably is an undescribed species.info:eu-repo/semantics/publishedVersio

Fontes, Jorge

Tempera, Fernando

Wirtz, Peter

English

Universidade do Algarve

On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores

Sapientia

 85SHORT COMMUNICATION ON SOME INTERESTING OPISTHOBRANCHS (MOLLUSCA, GASTROPODA) FROM THE AZORES  JORGE FONTES, FERNANDO TEMPERA & PETER WIRTZ FONTES, J., F. TEMPERA & P. WIRTZ 2001. On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores. Arquipélago. Life and Marine Sciences 18A: 85-87. Ponta Delgada. ISSN 0873-4704. The nudibranch Eubranchus farrani Alder and Hancock, 1844 is recorded from the Azores for the first time. The presence of the sacoglossan Placida cremoniana (Trinchese, 1892) in the Azores is confirmed. Pleurobranchus sp. from the Azores, Madeira and the Canary Islands is compared with P. garciagomesi Cervera et al. 1996; it probably is an undescribed species. J. Fontes (e-mail: fontes@notes.horta.uac.pt), F. Tempera & P, Wirtz; Universidade dos Açores, Departamento de Oceanografia e Pescas, Cais de Santa Cruz, PT - 9901-862 Horta, Portugal. INTRODUCTION WIRTZ (1998) summarized the state of knowledge on the opisthobranch gastropods of the Azores. He did, however, overlook a paper on deep-sea opisthobranchs by BOUCHET (1977). Since then, ORTEA et al. (1999) and ÁVILA (2000) have recorded additional species for this Atlantic archipelago. During diving surveys around Faial Island, we recently encountered three interesting opisthobranch species, on which we here report. MATERIAL AND METHODS The material was collected during the fieldwork carried out during the project MARÉ - a programme which includes the description of the shallow subtidal communities of three Sites of Community Interest (Habitats Directive) in the channel between Faial and Pico Islands as one of its objectives - and during an ongoing inventory of the shallow-water invertebrate fauna of the Azores by the third author. Specimens are collected whenever in situ identification is uncertain or not possible. Voucher material is deposited in the reference collection of the Department of Oceanography and Fisheries of the University of the Azores. Photos of live animals are deposited in the department’s image archives (ImagDOP). The species were identified with the help of SCHMEKEL & PORTMANN (1982), WEINBERG (1993), PICTON & MORROW (1994) and ORTEA et al. (1999). RESULTS Eubranchus farrani Alder and Hancock, 1844 (Nudibranchia, Arminiacea) During summer 1999, the first author encountered an individual of Eubranchus farrani Alder and Hancock, 1844 (Fig. 1) at Monte da Guia (western coast of Faial Island). Two additional animals were found at Baixa do Sul, an underwater seamount located between Faial and Pico Islands. All three animals were found in between 35 to 40 metres depth, feeding on hydroids of the genus Obelia. They ranged in size from 1.5 to 2 cm total length. The species is variable in colour with four different morphs (PICTON & MORROW 1994). The animals observed in the Azores belonged to the common morph usually found in the British Isles: translucent body with scattered yellow/orange  86patches on the dorsum and on the tips of the cerata, rhinophores and oral tentacles (cf. Fig. 1). In the British Isles, Eubranchus farrani is usually found in the shallow subtidal. Obelia hydroids do not occur in the shallow subtidal in the Azores and this might be the reason why E. farranni has not been collected previously.  The species is known from all around the British Isles and from Norway to western Mediterranean (PICTON & MORROW 1994). Placida cremoniana (Trinchese, 1892)  (Sacoglossa) In the middle of August 1999, while collecting data on the algal communities of Porto Pim bay (south-eastern coast of Faial island, Azores), the second author collected two Placida cremoniana. The two individuals were just a few centimetres apart on an algal turf dominated by Cladophora sp. and geniculated Corallinacea in a depth of ca. 4 m, over the jagged rocks located just off São Sebastião fortress. In late June 2000, the same author once again observed the species on a small reef near Feteira Islets (south coast of Faial). The single animal was on filamentous Chlorophyta growing on an Antipathes wollastoni colony at 20 m depth. A colour photo of the species can be found in WEINBERG (1993) and the Azorean specimens correspond perfectly to this. According to ORTEA et al. (1999) the known distribution of P. cremoniana comprises the Mediterranean Sea and the archipelagos of the Canaries, Madeira and the Azores. ORTEA et al. (1999) were the first to record the species from the Azores. They found P. cremoniana at São Miguel island, one of the islands of the eastern group of the Azores, whereas Faial is one of the islands of the central groups, about 300 km west of São Miguel. Pleurobranchus sp.  (Pleurobranchomorpha) While snorkelling at night in a large tidal pool at Varadouro, western coast of Faial Island, in September 1999, a large snail of the genus Pleurobranchus Cuvier, 1804 was encountered. The animal, shown in figure 2, had a body length of approximately 7 cm. It obviously belongs to the same species as the animal from the Canary Islands (photo by Rogelio Herrera) figured in Wirtz 1995, page 163 top, and the animal from Madeira island (photo by Joe Klenk) figured in WIRTZ 1999, plate 2, photo number 5. CERVERA et al. (1996) summarised the knowledge about the Mediterranean and eastern Atlantic Pleurobranchus species and described Pleurobranchus garciagomezi from the Cape Verde Islands. L. Cervera (personal communication to PW) suggested that the species from the Canary Islands and Madeira could be a colour morph of P. garciagomezi. This view was shared by MALAQUIAS (2000) who apparently found the same species at the Selvagens Islands (a small group of islands between the Canary Islands and Madeira). Fig. 3 shows a colour photo of P. garciagomezi taken at Tarrafal, north-western coast of São Tiago Island, Cape Verde Islands. The authors believe that the opisthobranch shown in Fig. 2 is an undescribed species of the genus Pleurobranchus. It differs from P. garciagomezi not only in its colour pattern but also in body shape and behaviour. A comparison of Figs. 2 and 3 shows the differences in colour: while Pleurobranchus garciagomezi from Cape Verde has conspicuous white lines on a cream-coloured to dark brown smooth body, Pleurobranchus sp. has a much denser network of much thinner pale lines on an orange-coloured slightly rugose body. The body shape of Pleurobranchus sp. is more ovoid and higher-backed than that of P. garciagomezi. The Pleurobranchus sp. captured at the Azores is larger than any P. garciagomezi recorded so far (the maximum size of P. garciagomesi given by CERVERA et al. (1996) is 5 cm). Finally, P. garciagomezi is a day-active species that can commonly be seen on open substrates throughout the day at the Cape Verde Islands (personal observations by the third author during ca. 60 dives between 1988 and 2000), whereas the two Pleurobranchus sp. from Madeira and the Azores were active at night and never encountered in about 1000 dives during the day (between 1983 and 2000) in these two archipelagos.  87 Fig. 1. Eubranchus farrani Alder and Hancock, 1844, Faial Island, Azores Islands (photo J. Fontes)   Fig. 2. Pleurobranchus sp., Faial Island, Azores (photo P. Wirtz).   Fig. 3. Pleurobranchus garciagomezi Cervera, 1996, São Tiago Island, Cape Verde Islands (photo P. Wirtz). REFERENCES ÁVILA, S. 2000. Shallow-water marine molluscs of the Azores: biogeographical relationships. Arquipélago. Life and Marine Sciences. Supplement 2 (A): 99-132. BOUCHET, P. 1977. Opisthobranches de profondeur de l’océan atlantique: II – Notaspidea et Nudibranchiata. The Journal of Molluscan Studies 43: 28-66. CERVERA, J.L., R. CATTANEO-VIETTI & M. EDMUNDS 1996. A new species of Notaspidean of the genus Pleurobranchus Cuvier, 1804 (Gastropoda, Opisthobranchia) from the Cape Verde Archipelago. Bulletin of Marine Science 59 (1): 150-157 MALAQUIAS, W.A.E. 2000. Additions to the knowledge of the opisthobranch molluscs of Selvagens Islands, NE Atlantic, Portugal. Arquipélago. Life and Marine Sciences. Supplement 2 (A): 89-98. ORTEA, J., L. MORO, J.J. BACALLADO & J. ESPINOSA 1999. Catálogo abreviado de las espécies del orden Sacoglossa (= Ascoglossa, Mollusca: Opisthobranchia) de las islas Canarias y de Cabo Verde. Revista de la Academia Canaria de Ciencias 1998 10 (4):85-96. SCHMEKEL, L. & A. PORTMANN 1982. Opisthobranchia des Mittelmeeres. Nudibranchia und Saccoglossa. Monografia della Stazione Zoologica di Napoli 40. Springer-Verlag, Berlin. I-x + 410 pp., 122 figs. 36 pls. WEINBERG, S. 1993. Découvrir la Mediterranée. Éditions Nathan, Paris. 352 pp. WIRTZ, P. 1995. Unterwasserführer Madeira Kanaren Azoren Niedere Tiere – Underwater Guide Madeira Canary Islands Azores Invertebrates. Naglschmid, Stuttgart. 247 pp. WIRTZ, P. 1998. Opisthobranch molluscs from the Azores. Vita Marina 45 (1-2): 1-16. WIRTZ, P. 1999. Opisthobranch molluscs from the archipelago of Madeira. Vita Marina 46 (1-2): 1-19.  Accepted 29 November 2000.   

The nudibranch Eubranchus farrani Alder and Hancock, 1844 is recorded from the Azores
for the first time. The presence of the sacoglossan Placida cremoniana (Trinchese, 1892) in the Azores is confirmed. Pleurobranchus sp. from the Azores, Madeira and the Canary Islands is compared with P. garciagomesi Cervera et al. 1996; it probably is an undescribed species

Repositório da Universidade dos Açores

 85 SHORT COMMUNICATION ON SOME INTERESTING OPISTHOBRANCHS (MOLLUSCA, GASTROPODA) FROM THE AZORES  JORGE FONTES, FERNANDO TEMPERA & PETER WIRTZ FONTES, J., F. TEMPERA & P. WIRTZ 2001. On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores. Arquipélago. Life and Marine Sciences 18A: 85-87. Ponta Delgada. ISSN 0873-4704. The nudibranch Eubranchus farrani Alder and Hancock, 1844 is recorded from the Azores for the first time. The presence of the sacoglossan Placida cremoniana (Trinchese, 1892) in the Azores is confirmed. Pleurobranchus sp. from the Azores, Madeira and the Canary Islands is compared with P. garciagomesi Cervera et al. 1996; it probably is an undescribed species. J. Fontes (e-mail: fontes@notes.horta.uac.pt), F. Tempera & P, Wirtz; Universidade dos Açores, Departamento de Oceanografia e Pescas, Cais de Santa Cruz, PT - 9901-862 Horta, Portugal. INTRODUCTION WIRTZ (1998) summarized the state of knowledge on the opisthobranch gastropods of the Azores. He did, however, overlook a paper on deep-sea opisthobranchs by BOUCHET (1977). Since then, ORTEA et al. (1999) and ÁVILA (2000) have recorded additional species for this Atlantic archipelago. During diving surveys around Faial Island, we recently encountered three interesting opisthobranch species, on which we here report. MATERIAL AND METHODS The material was collected during the fieldwork carried out during the project MARÉ - a programme which includes the description of the shallow subtidal communities of three Sites of Community Interest (Habitats Directive) in the channel between Faial and Pico Islands as one of its objectives - and during an ongoing inventory of the shallow-water invertebrate fauna of the Azores by the third author. Specimens are collected whenever in situ identification is uncertain or not possible. Voucher material is deposited in the reference collection of the Department of Oceanography and Fisheries of the University of the Azores. Photos of live animals are deposited in the department’s image archives (ImagDOP). The species were identified with the help of SCHMEKEL & PORTMANN (1982), WEINBERG (1993), PICTON & MORROW (1994) and ORTEA et al. (1999). RESULTS Eubranchus farrani Alder and Hancock, 1844 (Nudibranchia, Arminiacea) During summer 1999, the first author encountered an individual of Eubranchus farrani Alder and Hancock, 1844 (Fig. 1) at Monte da Guia (western coast of Faial Island). Two additional animals were found at Baixa do Sul, an underwater seamount located between Faial and Pico Islands. All three animals were found in between 35 to 40 metres depth, feeding on hydroids of the genus Obelia. They ranged in size from 1.5 to 2 cm total length. The species is variable in colour with four different morphs (PICTON & MORROW 1994). The animals observed in the Azores belonged to the common morph usually found in the British Isles: translucent body with scattered yellow/orange  86patches on the dorsum and on the tips of the cerata, rhinophores and oral tentacles (cf. Fig. 1). In the British Isles, Eubranchus farrani is usually found in the shallow subtidal. Obelia hydroids do not occur in the shallow subtidal in the Azores and this might be the reason why E. farranni has not been collected previously.  The species is known from all around the British Isles and from Norway to western Mediterranean (PICTON & MORROW 1994). Placida cremoniana (Trinchese, 1892)  (Sacoglossa) In the middle of August 1999, while collecting data on the algal communities of Porto Pim bay (south-eastern coast of Faial island, Azores), the second author collected two Placida cremoniana. The two individuals were just a few centimetres apart on an algal turf dominated by Cladophora sp. and geniculated Corallinacea in a depth of ca. 4 m, over the jagged rocks located just off São Sebastião fortress. In late June 2000, the same author once again observed the species on a small reef near Feteira Islets (south coast of Faial). The single animal was on filamentous Chlorophyta growing on an Antipathes wollastoni colony at 20 m depth. A colour photo of the species can be found in WEINBERG (1993) and the Azorean specimens correspond perfectly to this. According to ORTEA et al. (1999) the known distribution of P. cremoniana comprises the Mediterranean Sea and the archipelagos of the Canaries, Madeira and the Azores. ORTEA et al. (1999) were the first to record the species from the Azores. They found P. cremoniana at São Miguel island, one of the islands of the eastern group of the Azores, whereas Faial is one of the islands of the central groups, about 300 km west of São Miguel. Pleurobranchus sp.  (Pleurobranchomorpha) While snorkelling at night in a large tidal pool at Varadouro, western coast of Faial Island, in September 1999, a large snail of the genus Pleurobranchus Cuvier, 1804 was encountered. The animal, shown in figure 2, had a body length of approximately 7 cm. It obviously belongs to the same species as the animal from the Canary Islands (photo by Rogelio Herrera) figured in Wirtz 1995, page 163 top, and the animal from Madeira island (photo by Joe Klenk) figured in WIRTZ 1999, plate 2, photo number 5. CERVERA et al. (1996) summarised the knowledge about the Mediterranean and eastern Atlantic Pleurobranchus species and described Pleurobranchus garciagomezi from the Cape Verde Islands. L. Cervera (personal communication to PW) suggested that the species from the Canary Islands and Madeira could be a colour morph of P. garciagomezi. This view was shared by MALAQUIAS (2000) who apparently found the same species at the Selvagens Islands (a small group of islands between the Canary Islands and Madeira). Fig. 3 shows a colour photo of P. garciagomezi taken at Tarrafal, north-western coast of São Tiago Island, Cape Verde Islands. The authors believe that the opisthobranch shown in Fig. 2 is an undescribed species of the genus Pleurobranchus. It differs from P. garciagomezi not only in its colour pattern but also in body shape and behaviour. A comparison of Figs. 2 and 3 shows the differences in colour: while Pleurobranchus garciagomezi from Cape Verde has conspicuous white lines on a cream-coloured to dark brown smooth body, Pleurobranchus sp. has a much denser network of much thinner pale lines on an orange-coloured slightly rugose body. The body shape of Pleurobranchus sp. is more ovoid and higher-backed than that of P. garciagomezi. The Pleurobranchus sp. captured at the Azores is larger than any P. garciagomezi recorded so far (the maximum size of P. garciagomesi given by CERVERA et al. (1996) is 5 cm). Finally, P. garciagomezi is a day-active species that can commonly be seen on open substrates throughout the day at the Cape Verde Islands (personal observations by the third author during ca. 60 dives between 1988 and 2000), whereas the two Pleurobranchus sp. from Madeira and the Azores were active at night and never encountered in about 1000 dives during the day (between 1983 and 2000) in these two archipelagos.  87  Fig. 1. Eubranchus farrani Alder and Hancock, 1844, Faial Island, Azores Islands (photo J. Fontes)   Fig. 2. Pleurobranchus sp., Faial Island, Azores (photo P. Wirtz).   Fig. 3. Pleurobranchus garciagomezi Cervera, 1996, São Tiago Island, Cape Verde Islands (photo P. Wirtz). REFERENCES ÁVILA, S. 2000. Shallow-water marine molluscs of the Azores: biogeographical relationships. Arquipélago. Life and Marine Sciences. Supplement 2 (A): 99-132. BOUCHET, P. 1977. Opisthobranches de profondeur de l’océan atlantique: II – Notaspidea et Nudibranchiata. The Journal of Molluscan Studies 43: 28-66. CERVERA, J.L., R. CATTANEO-VIETTI & M. EDMUNDS 1996. A new species of Notaspidean of the genus Pleurobranchus Cuvier, 1804 (Gastropoda, Opisthobranchia) from the Cape Verde Archipelago. Bulletin of Marine Science 59 (1): 150-157 MALAQUIAS, W.A.E. 2000. Additions to the knowledge of the opisthobranch molluscs of Selvagens Islands, NE Atlantic, Portugal. Arquipélago. Life and Marine Sciences. Supplement 2 (A): 89-98. ORTEA, J., L. MORO, J.J. BACALLADO & J. ESPINOSA 1999. Catálogo abreviado de las espécies del orden Sacoglossa (= Ascoglossa, Mollusca: Opisthobranchia) de las islas Canarias y de Cabo Verde. Revista de la Academia Canaria de Ciencias 1998 10 (4):85-96. SCHMEKEL, L. & A. PORTMANN 1982. Opisthobranchia des Mittelmeeres. Nudibranchia und Saccoglossa. Monografia della Stazione Zoologica di Napoli 40. Springer-Verlag, Berlin. I-x + 410 pp., 122 figs. 36 pls. WEINBERG, S. 1993. Découvrir la Mediterranée. Éditions Nathan, Paris. 352 pp. WIRTZ, P. 1995. Unterwasserführer Madeira Kanaren Azoren Niedere Tiere – Underwater Guide Madeira Canary Islands Azores Invertebrates. Naglschmid, Stuttgart. 247 pp. WIRTZ, P. 1998. Opisthobranch molluscs from the Azores. Vita Marina 45 (1-2): 1-16. WIRTZ, P. 1999. Opisthobranch molluscs from the archipelago of Madeira. Vita Marina 46 (1-2): 1-19.  Accepted 29 November 2000.   

On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores.

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On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores

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