the journal of biodiversity data © Check List : > PENSOFT. NOTES ON GEOGRAPHIC DISTRIBUTION Check List 19 (2): 163-168 https://doi.org/10.15560/19.2.163 New records of mesopelagic siphonophores (Cnidaria, Hydrozoa) from the Colombian Caribbean collected during offshore exploration cruises CRISTINA CEDENO-Posso!", EDGAR FERNANDO DORADO-RONCANCIO! 1 Programa de Biodiversidad y Ecosistemas Marinos, Linea de Inventarios, Taxonomia y Biologia de Especies, Instituto de Investiga- ciones Marinas y Costeras, Playa Salguero, Santa Marta, Magdalena, Colombia « CCP: cristina.cedeno@invemar.org.co ® https:// orcid.org/0000-0001-8622-2947 « EFDR: edgar.dorado@invemar.org.co ® https://orcid.org/0000-0002-0321-5416 * Corresponding author Abstract. Five species of siphonophores are newly recorded in the Colombian Caribbean Sea: the physonects Athorybia rosacea (Forsskal, 1775), Nanomia bijuga (Delle Chiaje, 1844), and Agalma okenii Eschscholtz, 1825 and the calycophores Amphicaryon ernesti Totton, 1954 and Hippopodius hippopus (Forsskal, 1776), from samples col- lected with deep-water trawls in six hydrocarbon exploration areas (GUA OFF 3, COL 1, COL 2, COL 3, COL 4; COL 10) where research projects were undertaken in 2013 and 2018 by the Marine and Coastal Research Institute “Jose Benito Vives de Andreis” in agreement with the National Hydrocarbon Agency. Keywords. Biodiversity, Calycophorae, distribution, Physonectae Academic editor: Ricardo Gonzalez-Mufioz Received 19 July 2022, accepted 3 February 2023, published 10 March 2023 Cedefio-Posso C, Dorado-Roncancio EF (2023) New records of mesopelagic siphonophores (Cnidaria, Hydrozoa) from the Colombian Caribbean collected during offshore exploration cruises. Check List 19 (2): 163-168. https://doi.org/10.15560/19.2.163 Introduction Siphonophores are colonial, oceanic, holoplanktonic animals not permanently attached to a substrate, with the exception of those in the family Rhodaliidae which are epibenthic. Siphonophores present three types of body plans, according to their suborder (Dunn et al. 2005). The most common and easily recognizable sub- order is Calycophorae, which has two nectophores (anterior and posterior) but no pneumatophore. The suborder Cystonectae has a gas-filled float, called a pneumatophore, and a long-stemmed siphosome, and the suborder Physonectae bears a pneumatophore, a nectosome with multiple swimming units (necto- phores), and a long-stemmed siphosome (Mapstone 2014; Dunn et al. 2005). Apart from the typical siphonophore that is well recognized (Physalia physalis cystonect), the study of siphonophores in Colombian waters has been limit- ed because there are few researchers dedicated to the taxonomy of this group; siphonophores are polymor- phism and, like all gelatinous plankton, they are also extremely fragile organisms and have the ability to au- totomize as a defense mechanism, a phenomenon that occurs when they are collected with plankton nets, mak- ing their identification and classification difficult (Dunn et al. 2005; Haddock et al. 2005). For this reason, the taxonomy of this group is often based on parts of the col- ony, such as its bracts, pneumatophores, or young colo- nies (Dunn et al. 2005). The characterization of planktonic communities is an essential component of environmental baseline studies. Given the dependence of these communities on their fluid environment, these planktonic organisms are reliable indicators of an ecosystem’s state and health (Vides 2019). In the Colombian Caribbean Sea, 23 spe- cies of siphonophores have been reported in the latest checklist by Oliveira et al. (2016). Most of these species were collected for zooplankton studies in coastal ar- eas using horizontal plankton trawls to depths of 50 m. ©The authors. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 164 Since 2013, through agreements between Marine and Coastal Research Institute “Jose Benito Vives de An- dreis” (Invemar) and the National Hydrocarbons Agen- cy (ANH), plankton have been sampled in exploration blocks in the Colombian Caribbean using vertical plankton trawls to obtain samples at various depths in the water column, down to 1000 m, with more attention paid depths below 70 m. In the resulting samples, we found five siphonophore species (from two suborders) which are newly recorded from the Colombian Carib- bean Sea. These results highlight the need to train spe- cialists in this group and continue sampling not only in the epipelagic zone (0-200 m) but also in the mesope- lagic zone (200-1000 m). Methods Zooplankton samples have been obtained in seven ex- ploration blocks in the Colombian Caribbean (GUA OFF 3 [2013], COL 4 and 5 [2014], COL 2 [2015], COL 1 [2016]; COL 3 [2017]; COL 10 [2018]) for a total of 61 stations, mostly during the rainy season (November- December), except for COL 1 which was taken during the dry season. Invemar, as an entity linked to Min- isterio de Ambiente y Desarrollo Sostenible (Art.18, Law 99 of 1993), does not require a permit to collect specimens (Paragraph 1. Art. 2.2.2.2.8.1.2., Decree 1076 of 2015). Vertical stratified trawls of zooplankton were carried out at the 61 stations at four depth ranges (0-60 m, 70-140 m, 170-340 m, 540-1000 m) using a General Oceanic double trip mechanism, with 200 pm and bongo nets and a 0.6 m mouth diameter. The sam- ples were narcotized with 10% magnesium chloride and fixed with formaldehyde and neutralized with so- dium tetraborate (borax), leaving the solution at a 5% concentration. Siphonophores were separated and identified with a Leica M205A stereomicroscope and dissected with a Zeiss Primo Star light microscope. We contrasted their specific taxonomic characters with current literature to confirm the taxonomic identities of each specimen (Totton and Bargmann 1965; Pugh 1999; Licandro et al. 2017). The specimens were deposited in the Cnidaria reference collection with their respective catalog num- bers of Museo de Historia Natural Marina de Colom- bia (MHNMC) of Invemar (institution code INV CNI). Some specimens were too deteriorated to be included in this reference collection, but they can be located with the museum’s consecutive number in the plankton sec- tion (ZOOP). The catalog numbers of each specimen are listed in the material examined section, along with the identification section which has information on how the species was recognized. Results Of the seven exploration blocks and 61 stations ana- lyzed, only 16 stations showed the presence of 23 spec- imens of siphonophores that had not been previously Check List 19 (2) recorded for the Colombian Caribbean. Three species belong to the suborder Physonectae and family Agalma- tidae: Athorybia rosacea (Forsskal, 1775) was found at four stations (COL 3-E 564; COL 10-E 617; GUA OFF 3-E 358, E 372); Nanomia bijuga (Delle Chiaje, 1844) was found at 3 stations (COL 1-E 437, E 446; GUA OFF 3-E 357); Agalma okenii Eschscholtz, 1825 was found at 3 stations (COL 1-E 456, E 466; GUA OFF 3-E 358). Two species belong to the suborder Calycophorae and the families Prayidae and Hippopodiidae: Amphicary- on ernesti Totton, 1954 was found at seven stations (COL 1-E 437, E 466, E 467; COL 2-E 418, E 431; COL 4-E 380; COL 10-E 617; GUA OFF 3-E 358) and Hip- popodius hippopus (Forsskal, 1776) was found at 6 sta- tions (COL 1-E 467; COL 10-E 600, E 617; COL 2-E 421; COL 4- E 380, E 383) (Fig. 1). Systematic account Suborder Physonectae Haeckel, 1888 Family Agalmatidae Brandt, 1834 Athorybia rosacea (Forsskal, 1775) Figure 2A Material examined. COLOMBIA - CarIBBEAN SEA ¢ offshore, exploration block GUAOFF 3 - E 358; 12° 50'28"N, 073°34'34"W; 170-340 m depth; 20.X1.2013; INV CNI4613 « GUAOFF 3 - E 372; 12°18'25"N, 073° 31'5"W; 0-60 m depth; 11.XII.2013; INV CNI4614 - COL 3 - E 564; 11°58'57"N, 074°59'38"W; 70-140 m depth; 4.X.2017; consecutive number: 62016 « COL 10 - E 617; 13°30'22"N, 072°40'25"W; 0-60 m depth; 1-VI. 2018; consecutive number: ZOOP 66374. Identification. There are two accepted species of Atho- rybia Eschscholtz, 1829, A. rosacea, and A. lucida Biggs, 1978 (Schuchert 2022). Two of the most distinguish- ing characteristics of these genus is the large, red-pig- mented pneumatophore, making up almost the entire volume of the colony (Fig. 2A) and the absence of nec- tosomes. Four colonies observed in this study (not all of them were in good condition and were not deposited in the reference collection) had an average width of 10 mm. There are few bracts attached along the short stem, giving the colonies a typical rose-petal shape. Nanomia bijuga (Delle Chiaje, 1844) Figure 2B Material examined. COLOMBIA - CarIBBEAN SEA offshore, exploration block GUAOFF 3 - E 357; 12°50' 46"N, 073°50'24"W; 70-140 m depth; 19.XI.2013; INV CNI4615 ¢ COL 1 - E 437; 12°35'0"N, 074°7'30"W; 70- 140 m depth; 10.IV.2016; consecutive number: ZOOP 56181. COL 1 - E 446; 12°45'0"N, 074°52'30"W; 70-140 m depth; 14.IV.2016; consecutive number: ZOOP 56189. Identification. There are two accepted species of Na- nomia A. Agassiz, 1865, N. cara Agassiz, 1865 and N. bi- juga (Delle Chiaje, 1844) (Totton and Bargmann 1965; Schuchert 2022). Three colonies were observed in this study (not all of them were in good condition and were Cedeno-Posso and Dorado-Roncancio | New records of siphonophores in Colombia Caribbean Sea » _ COLOMBIA South America —_ 11°40'0"N 10°0'0"N i 76°30'0"W 74°50'0"W QLOMBYA 165 ee ) - _ ® Agalma okenii _ @ Amphicaryon ernesti @ Athorybia rosacea j 4 @ Hippopodius hippopus _ _™ @ Nanomia bijuga : an T fA 73°10'0"W 71°30'0"W Figure 1. Location of the stations and exploration blocks where siphonophores were collected in 2013 and 2018. Map produced by the Invemar LabSIS information systems laboratory. not deposited in the reference collection). One of them was a young colony with a width of 12 mm; adult colo- nies reach 100-450 mm long when in a state of con- traction, according to Totton and Bargmann (1965). The nectophores of the colony were deteriorated or lost during collection; their identification was based on the bracts and the unicornuate tentilla at the base of the in- volucre (Fig. 2B) (Alvarifio 1981). Agalma okenii Eschscholtz, 1825 Figure 3A Material examined. COLOMBIA - CarIBBEAN SEA offshore, exploration block COL 1 - E 456; 12°55'00"N, 075°22'30" W; 70-140 m depth; 17.IV.2016; INV CNI4616 e GUAOFF 3 - E 358; 12°50'28"N, 073°34'34"W; 170- 340 m depth; 20.X1.2013; consecutive number: 63100 « COL 1 - E 466; 12°05'00"N, 075°37'30"W; 540-1000 m depth; 20.IV.2016; consecutive number: ZOOP 56211. Identification. It is the type species of Agalma Esch- scholtz, 1825; there are three accepted species: A. clausi Bedot, 1888, A. elegans (Sars, 1846) and A. okenii (Tot- ton and Bargmann 1965; Schuchert 2022). Four colo- nies were observed in this study (not all of them were in good condition and were not deposited in the reference collection). Two of colonies were young and had an av- erage width of 13 mm; the nectophore height reaches 12 mm in adult colonies according to Pugh (1999). The nectophores of the colonies had deteriorated during their collection; their identification was based on the bracts, which have four distal facets, and the tricornu- ate tentilla, which have an ampulla and two terminal filaments (Fig. 3A) (Pugh 1999). Suborder Calycophorae Leuckart, 1854 Family Prayidae Kolliker, 1853 Subfamily Amphicaryoninae Chun, 1888 Amphicaryon ernesti Totton, 1954 Figure 3B Material examined. COLOMBIA - CARIBBEAN SEA offshore, exploration blocks; COL 4 - E 380; 11°10'41"N, 076°50'11"W; 70-140 m depth; 23.X.2014; INV CNI 4617 » COL 2 - E 418; 12°25'0"N, 074°52'30"W; 70- 140 m depth; 25.XI.2015; INV CNI4618 « COL 10 - E 617; 13°30'22"N, 072°40'25"W; 70-140 m depth; 1.VI.2018; INV CNI4619 « COL 1 - E 437; 12°35'0"N, 074°7'30"W; 70-140 m depth; 10.IV.2016; consecutive number: ZOOP 56181 « COL 1 - E 466; 12°05’00"N, 075°37'30"W; 70-140 m depth; 20.IV.2016; consecutive 166 Check List 19 (2) Figure 2. Newly reported siphonophore species from the Colombian Caribbean Sea, collecting. Physonect zooids: A. Athorybia rosacea, less bracts. B. Nanomia bijuga. Labels: b = bract; gz = gastrozooid; pn = pneumatophore (float); t = tentacle with tentilla; te = tentilla; inv = involucre. number: ZOOP 56209 « COL 1 - E 467; 12°05'00"N, 075°52'30"W; 70-140 m depth; 21.IV.2016; consecutive number: ZOOP 56213 « COL 2 - E 431; 11°45’00’N, 075°37'30"W; 70-140 m depth; 3.XII.2015; consecutive number: ZOOP 56249. Identification. There are three accepted species of Am- phicaryon Chun, 1888: A. acaule Chun, 1888, A. ernesti, and A. peltifera (Haeckel, 1888) (Totton and Bargmann 1965; Schuchert 2022). This study found seven poly- gastric phases of A. ernesti (not all specimens were in good condition, and not all were deposited in the ref- erence collection); these had an average height of 8.5 mm; the nectophore height of adult colonies reaches 8 mm according to Pugh (1999). The specimens were identified by two characteristics: the definitive necto- phore is not embraced by the larval one, and the os- tium has lost contact with the nectophore surface but is connected by a fine strand of tissue (Fig. 3B) (Map- stone 2009). Family Hippopodiidae Kolliker, 1853 Hippopodius hippopus (Forsskal, 1776) Figure 3C Material examined. COLOMBIA - CARIBBEAN SEA e offshore, exploration blocks; COL 4 - E 380; 11°10'41"N, 076°50'11"W; 170-340 m depth; 23.XI.2014; INV CNI 4620 « COL 4 - E 383; 10°40’4"N, 076°05'21"W; 540- 1000 m depth; 27.X1.2014; INV CNI4621 » COL2-E 421; 11°55'00"N, 075°07'30" W; 170-340 m depth; 29.XI. 2015; INV CNI4622 « COL 1 - E 467; 12°05'00"N, 075° 52'30"W; 170-340 m depth; 21.V.2016; INV CNI4623 « COL 10 - E 600; 14°22'12"N, 072°13'48"W, 170-340 m depth; 12-VI.2018; INV CNI4624 « COL 10 - E 617; 13° 30'22"N, 072°40'25"W; 170-340 m depth; 1.V1.2018; consecutive number: ZOOP 66375. Identification. Hippopodius Quoy & Gaimard, 1827 is monotypic genus (Totton and Bargmann 1965). Two of the most representative characteristics of H. hippopus Cedefo-Posso and Dorado-Roncancio | New records of siphonophores in Colombia 1 mm 167 Figure 3. Newly recorded siphonophore species from the Colombian Caribbean Sea. Physonect zooids: A. Agalma okenii, caly- cophores. B. Amphicaryon ernesti, polygastric phase in lateral view. C. Hippopodius hippopus, nectophore. Labels: b = bract; gz = gastrozooid; pn = pneumatophore (float); t = tentacle with tentilla; te = tentilla; inv = involucre; am = ampulla; tf = terminal filament; In = larval nectophore; df = defninitive nectophore; ns = nectosac; o = ostium; kn = knob. are that the nectophore is shaped like a horse’s hoof and the four rounded dorsal knobs vary in size and form an arc above the ostium (Fig. 3C) (Totton and Bargmann 1965). Six nectophores observed in this study (not all of them were in good condition and not all were deposited in the reference collection). They had an average height of 8.1 mm; adult colonies reach 20 mm high according to Pugh (1999). Discussion According to the most updated revision of siphonophore species in the Colombian Caribbean (Oliveira et al. 2016), the family Agalmatidae is represented by Agalma elegans, Halistemma striata, Nanomia cara, and Lychnagalma utricularia, the family Prayidae by Praya reticulata and Rosacea cymbiformis, and the family Hippopodiidae by Vogtia pentacantha and Vogtia spinosa. Therefore, the five species of siphonophores reported here are newly re- corded in Caribbean Colombian waters. The physonects Athorybia rosacea, Nanomia bijuga, and Agalma oke- nii, and the calycophores Amphicaryon ernesti and Hip- popodius hippopus have been previously recorded in the western Caribbean Sea and Gulf of Mexico (Gasca 2002, 2009; Pugh and Gasca 2009) and in the Atlantic Ocean (Brazil to Argentina) by Oliveira et al. (2016). Athorybia rosacea, which was collected at depths of 0-340 m, is an epi- and mesopelagic species found in the water column in the northeastern Colombian Ca- ribbean blocks COL 3, GUA OFF 3, and COL 10, which correspond to the Magdalena River influence zone, the oceanic Colombian zone, and offshore north-east zone (Aruba Passage), respectively (Dorado-Roncancio et al. 2022) (Fig. 1). The records reported here are the first of this short-stem agalmatid species from Colombian Ca- ribbean waters; the species is now known from both the Caribbean Sea and the Pacific Ocean. Nanomia bijuga was collected at depths of 70-140 m, and it is an epi- and mesopelagic species that undergoes short- and long-distance vertical diel migrations (Bar- ham 1963; Pugh 1999). It was found in the water column in the northeastern Colombian Caribbean in blocks GUAOFF 3 and COLI, which correspond to the oceanic Colombian zone (Dorado-Roncancio et al. 2022; Fig. 1). Previous records Colombian waters were from the Pacific Ocean (Oliveira et al. 2016; Uribe-Palomino et al. 2018). 168 Agalma okeniiis an epi- to mesopelagic species, which was collected at depths of 70-1000 m in the northeast- ern Colombian Caribbean in blocks GUA OFF 3, COL 1, and COL 2, which correspond to the oceanic Colom- bian zone (Dorado-Roncancio et al. 2022; Fig. 1). Pre- vious records in Colombia waters were from the Pacific Ocean (Oliveira et al. 2016; Uribe-Palomino et al. 2018). Amphicaryon ernesti was collected at depths of 70- 140 m. It is an epipelagic species, which was collected in the northeastern Colombian Caribbean blocks COL 1, COL 2, COL 4, and COL 10. These areas correspond to the oceanic Colombian zone and offshore northeast zone (Aruba Passage) (Dorado-Roncancio et al. 2022; Fig. 1). Previously, this species has been recorded in Co- lombian Pacific waters (Oliveira et al. 2016). Hippopodius hippopus is an epi- and mesopelagic spe- cies that undergoes small-scale diel migrations (Pugh 1999). This species was collected at depths between 170 and 1000 m in the northeastern Colombian Caribbean blocks COL 4, COL 2, COL 1, and COL 10. These blocks which correspond to the oceanic Colombian zone and offshore north-east zone (Aruba Passage) (Dorado-Ron- cancio et al. 2022; Fig. 1). Alvarifio (1981) hypothesized that the initial stages of development of H. hippopus oc- cur in the mesopelagic or bathypelagic strata, away from the surface waters. Previous records of H. hippopus in Colombian waters were from the Pacific Ocean (Oliveira et al. 2016; Uribe-Palomino et al. 2018). Acknowledgements We thank the National Hydrocarbons Agency (ANH) and to the Marine and Coastal Research Institute “Jose Benito Vives de Andreis” (Invemar) for the co-financ- ing the research and for logistic support (agreements 171-2013, 188-2014, 290-2015, 167-2016, 379-2017, 340- 2018). We thank Felipe Valencia from the LabSIS in- formation systems laboratory of the Coordination of Research and Information for Marine and Coastal Management (GEZ) for the map elaboration, GTSEM -Taxonomy, Systematics and Marine Ecology Research Group of Invemar for their collaboration and good friendship. We also thank the editors and reviewers for their helpful comments and suggestions. This is contribution no. 1353 of the Marine and Coastal Research Institute (Invemar). Authors Contributions Conceptualization: CCP. Data curation: CCP. Investi- gation: CCP, EFDR. 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