Cirrholovenia Polynema (Hydrozoa: Leptothecata) in the Western Atlantic Ocean
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Ocean BRIEF COMMUNICATION and Coastal https://doi.org/10.1590/2675-2824069.20-001egt Research ISSN 2675-2824 First record of Cirrholovenia polynema (Hydrozoa: Leptothecata) in the Western Atlantic Ocean Everton Giachini Tosetto1,* , Sigrid Neumann-Leitão1 , Arnaud Bertrand1,2,3 , Miodeli Nogueira Júnior4 1 Departamento de Oceanografia, Universidade Federal de Pernambuco, Avenida Arquitetura, S/N, 50670-901, Recife, PE, Brazil. 2 Institut de Recherche pour le Développement (IRD), MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France 3 Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, Rua D. Manuel de Medeiros, S/N, 52171-900, Recife, PE, Brazil 4 Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, Cidade Universitária, 58051-900, João Pessoa, PB, Brazil *Corresponding author: [email protected] Meroplanktonic hydromedusae of the family ecosystem functioning (Tewksbury et al. 2014, Hays Cirrholoveniidae Bouillon, 1984 are distinguished et al. 2018). During two cruises characterizing the from other Leptothecata medusae mainly by the zooplanktonic communities from the tropical and presence of four simple radial canals, marginal cirri, equatorial Western Atlantic Ocean (Bertrand 2015, at least four closed statocysts and absence of a Neumann-Leitão et al. 2018, Tosetto et al. 2019) gastric peduncle (Bouillon 1999, Bouillon et al. 2006). specimens of C. polynema were observed for the first The genus Cirrholovenia Kramp, 1959 is to date the time on the Western side of the Atlantic Ocean. In sole representative of Cirrholoveniidae, presenting the present study, we report these occurrences and characteristics of the family (Bouillon and Boero provide a detailed review of the global distribution 2000, Bouillon et al. 2006, Schuchert 2020). of the species along with some insights into the Cirrholovenia was described with the species taxonomy of the group. Cirrholovenia polynema Kramp, 1959 and Specimens were obtained during the “Camadas Cirrholovenia tetranema Kramp, 1959 collected in Finas III” survey conducted in October, 2012, the Indo-Pacific. The genus was first included in the aboard the research vessel NHo. Cruzeiro do Sul - family Lovenellidae Russell, 1953 (Kramp 1959) and H38 (DHN/Brazilian Navy) off North Brazil and the later classified as a new family by Bouillon (1984). “Acoustics along the Brazilian coast (ABRACOS 1)” Two additional species were described in the genus, survey conducted in October 2015, aboard the Cirrholovenia reticulata Xu & Huang, 2004 and French R/V ANTEA off Northeast Brazil (Coordinates: Cirrholovenia violacea Gershwin, Zeidler & Davie, 7.5°N, 46.0°W; 8.0°N, 42.0°W; 7.0°N, 38.0°W; 2.0°N, 2010, both in the Western Pacific Ocean (Xu and 38.0°W; 3.93°S, 32.52°W). Samples were collected in Huang 2004, Gershwin et al. 2010), resulting in four oblique hauls, using a bongo plankton net with 300 valid species to date (Schuchert 2020). µm mesh and 0.6 m opening, from near bottom to Hydromedusae are diversified, important surface over the continental shelf, and 200 m depth predators in marine habitats; information on their to surface in open waters. Material was fixed with distribution is essential for understanding species 4% formaldehyde buffered with sodium tetraborate diversity, biogeographic patterns and marine (0.5 g L-1). Specimens were deposited in the Museu de Invertebrados Paulo Young from Universidade Federal Submitted on: 08-August-2020 Approved on: 19-September-2020 da Paraíba (CIPY1121, CIPY 1124, CIPY 1125). The seven specimens sampled presented a Editor: Rubens M. Lopes lenticular umbrella ranging from 2.4 to 6 mm © 2021 The authors. This is an open access article distributed under the terms of the Creative Commons license. wide (Fig. 1 a; b), with thin mesoglea. The velum is Ocean and Coastal Research 2021, v69:e21006 1 Tosetto et al. Cirrholovenia polynema in the Atlantic Ocean broad. Manubrium were large with crenulated lips rudimentary bulbs and reticular papillae on the (Fig. 1 a; b). Only one of the specimens presented exumbrella (Xu and Huang 2004; Table 1), typically gonads, which were still developing along the present in recently released medusae (Bouillon et middle of the four radial canals (Fig. 1 b). The al. 2006). Moreover, considering that only a single two largest species presented 12 fully developed small medusa of C. reticulata has been described, it tentacles with heart-shaped bulbs and about two is not known whether the rudimentary bulbs will or three rudimentary bulbs between them (Fig. develop tentacles or remain rudimentary as the 1 a; b). Up to eight marginal cirri and one or two medusa grows. Thus, C. reticulata may be a juvenile closed statocysts distributed between successive of another species, a hypothesis that should be tentacles (Fig. 1 c). tested pending more specimens to be found and/ The four radial canals, presence of closed or molecular analyses performed. In any case, statocysts and marginal cirri, and absence of a the present specimens match with C. polynema, gastric peduncle assigned the specimens to the which may have up to 20 marginal tentacles, linear family Cirrholovenidae and genus Cirrholovenia gonads along the middle portion of radial canals (Bouillon et al. 2006). Among the four currently and up to eight marginal cirri and two statocysts described species in the genus, C. tetranema differs between adjacent tentacles (Kramp 1959; Table 1). from present specimens by always having four The remaining species of the genus, C. marginal tentacles and no rudimentary bulbs. violacea, was described with a short and broad Its umbrella typically higher than flatter and gastric peduncle (Gershwin et al. 2010). However, cylindrical gonads, occupying almost the whole the absence of gastric peduncle is a remarkable length of the radial canals, also differ in shape characteristic distinguishing Cirrholovenidae from and position from our specimens (Kramp 1959, other Leptothecata medusae with closed statocysts Bouillon et al. 2004; Table 1). C. reticulata also such as Lovenellidae, where the genus Cirrholovenia was described with only four marginal tentacles. was previously included, and Eirenidae Haeckel, 1879 However, this species was described based on medusae (Kramp 1959, Bouillon 1984, Bouillon et a single small specimen (0.8 mm) presenting al. 2006). This issue was apparently overlooked in Figure 1. Cirrholovenia polynema medusae from North Brazil. (a and b) Oral view. (c) Detail of bell margin showing statocysts and marginal cirri. Ocean and Coastal Research 2021, v69:e21006 2 Tosetto et al. Cirrholovenia polynema in the Atlantic Ocean the C. violacea description; it seems likely that the into one of these two species. Further analysis of the species has been included in the wrong family and material is necessary to elucidate this question. genus. Among Eirenidae, the genus Phialopsis Torrey, C. polynema was first described from the Java Sea 1909 include species with a short and broad gastric (Kramp 1959), and is widely distributed in tropical and peduncle, more than 8 statocysts and marginal cirri, subtropical areas from the Indo-Pacific, mainly between matching with the description of the specimen 30°N and 30°S (Kramp 1959, 1962, 1965, Bouillon et al. classified as C. violacea. Although it differed in 1986, Du et al. 2012; Fig. 2). Occurrences outside this the number of marginal structures and shape of range also were recorded in temperate areas off New the gonads from the other two known species of Zealand and Chile (Kramp 1965, Fagetti 1973; Fig. 2). In Phialopsis (Table 1), the description was based on a the Atlantic Ocean the species was only recorded in St. small and immature individual that could develop Helena Bay, South Africa (Buecher and Gibbons 2000, Gibbons and Buecher 2001; Fig. 2), this area is under Table 1. Comparison of main characteristics of the valid medusae species from the genus Cirrholovenia and Phialopsis NI = Not informed. Species Bell diameter Tentacles Rudimentary bulbs Marginal cirri Up to 3 between successive Up to 8 between successive Present specimens 2.4 to 6 mm Up to 12 tentacles tentacles Cirrholovenia polynema Up to 8 between successive Up to 8 mm Up to 20 Few Kramp, 1959 tentacles Cirrholovenia tetranema Up to 8 between successive Up to 1.5 mm 4 None Kramp, 1959 tentacles Cirrholovenia reticulate Xu & Up to 0.8 4 1 between successive tentacles 5 between successive tentacles Huang, 2004 Cirrholovenia (?) violacea Gershwin, Zeidler & Davie, 1.34 mm 12 Apparently absent Same number as statocysts 2010 Phialopsis diegensis Torrey, 8-9 between successive More numerous than marginal NI 16-28 1909 tentacles papillae Phialopsis averruciformis Huang, Xu & Lin, 2013 3 - 5 between successive 32 mm 52 Absent tentacles Species Statocysts Gonads Reference 1 or 2 between successive Linear, along the middle of radial Present specimens This study tentacles canals Cirrholovenia polynema Kramp, Linear, along the middle of radial Twice as numerous as tentacles Kramp, 1959 1959 canals Thick and cylindrical, occupying Cirrholovenia tetranema Kramp, 1 or 2 between successive almost the whole length of the Kramp, 1959 1959 tentacles radial canals Cirrholovenia reticulate Xu & Cylindrical, occupying almost the 1 between successive tentacles Xu & Huang, 2004 Huang, 2004 whole length of the radial canals Cirrholovenia (?) violacea Gershwin et al, 3 - 5 between successive tentacles On the middle of radial canals Gershwin, Zeidler & Davie, 2010 2010 Linear, occupying 3/4 of the distal Phialopsis diegensis Torrey, 1909 2 - 5 between successive tentacles Torrey, 1909 portion of radial canals Phialopsis averruciformis Huang, Xu & Lin, 2013 Linear, extending from the basal 1 or 2 between successive part of peduncle to almost to the Wang et al, 2013 tentacles bell margin Ocean and Coastal Research 2021, v69:e21006 3 Tosetto et al. Cirrholovenia polynema in the Atlantic Ocean Figure 2. Global distribution of Cirrholovenia polynema based on this study and published records. The continuous line shows the 250-m isobath, roughly corresponding to the shelf break (generated using Ocean Data View software; Schlitzer, 2007).