An Acad Bras Cienc (2020) 92(Suppl. 2): e20180933 DOI 10.1590/0001-3765202020180933 Anais da Academia Brasileira de Ciências | Annals of the Brazilian Academy of Sciences Printed ISSN 0001-3765 I Online ISSN 1678-2690 www.scielo.br/aabc | www.fb.com/aabcjournal BIOLOGICAL SCIENCES Dendrapta nasicola n. sp. (Copepoda: Running title: Dendrapta nasicola Siphonostomatoida: Lernaeopodidae) a parasite n. sp. from the olfactory sacs of Bathyraja scaphiops Academy Section: BIOLOGICAL (Norman, 1937) in the South Western Atlantic SCIENCES MANUEL M. IRIGOITIA, VERÓNICA TAGLIORETTI & JUAN T. TIMI e20180933 Abstract: During a parasitological survey of the olfactory sacs of 21 species of Rajiformes (Chondrichthyes) from the Southwestern Atlantic Ocean, copepods referable to Dendrapta Kabata (1964) (Siphonostomatoida: Lernaeopodidae) were found parasitizing 92 the cuphead skate Bathyraja scaphiops (Rajiformes: Arhynchobatidae). Morphological (Suppl. 2) analyses using both light and electron microscopy revealed that they belong to a new 92(Suppl. 2) species. It can be easily distinguished from its congeners by the ratio between lengths of posterior process and trunk (1:0.8), the large to width ratio of trunk (1:0.7) and the armature of the antennule (1, 1, 5 + 1 aesthete). Dendrapta cameroni longiclavata is raised to full specifi c status, as Dendrapta longiclavata n. comb. Kabata & Gusev, 1966. Key words: Bathyraja scaphiops, Dendrapta, Mar Argentino, South West Atlantic. INTRODUCTION Gilbert, 1880 from British Columbia and in the Canadian Pacifi c (Kabata 1970). To the best of Dendrapta Kabata, 1964 is a monotypic genus of our knowledge, the last report of a member of lernaeopodid copepods parasites of rajid fi shes this copepod genus was that of D. cameroni on from the Northern Hemisphere. This genus its type host, from the Canadian Atlantic (Khan was erected by Kabata (1964) to accommodate et al. 1980). D. cameroni (Heller 1949), originally described During parasitological studies on the as Charopinus cameroni Heller, 1949 from the parasites of the olfactory sacs of 21 species of external surface, near the fi n bases, of Amblyraja Rajiformes from the Argentinian continental radiata (Donovan, 1808) (as Raja scabrata shelf, Southwestern Atlantic, parasitic copepods Garman, 1913) from the coasts of Quebec, referable to Dendrapta were found only on Canadian Atlantic. Later on, Kabata & Gusev Bathyraja scaphiops (Norman, 1937). They were (1966) described the subspecies D. cameroni found to be representatives of an undescribed longiclavata Kabata & Gusev, 1966 from the skin of species of Dendrapta, which is herein described. the ocellate spot skate Okamejei kenojei (Müller The ZooBank Life Science Identifier & Henle, 1841), Bathyraja smirnovi (Soldatov & (LSID) of this publication is: urn:lsid:zoobank. Pavlenko, 1915) (as Raja kenojei and R. smirnovi, org:pub:1490E34D-A419-4475-9945- respectively) and of an unidentifi ed species of 88BC907469B3. the same genus from the Kamchatkan Peninsula and Sakhalin Island, Russia. This subspecies was successively reported on Raja inornata Jordan & An Acad Bras Cienc (2020) 92(Suppl. 2) MANUEL M. IRIGOITIA, VERÓNICA TAGLIORETTI & JUAN T. TIMI Dendrapta nasicola N. SP. MATERIALS AND METHODS For scanning electron microscopy (SEM), two specimens were dehydrated using a graded A total of 851 skates belonging to 21 species of series of ethanol washed up to 100%, then dried Rajiformes (Table I) were examined for parasites. by evaporation with hexamethyldisilazane, Most fish were obtained from commercial sputter-coated with gold palladium and trawlers in waters off the Buenos Aires province, examined using a JEOL JSM 6460LV SEM (JEOL, Argentina, between 2013 and 2018. Additional Tokyo, Japan). samples of Sympterygia bonapartii Müller & Type material was deposited in the Henle, 1841, Dipturus brevicaudatus (Marini 1933), Carcinological Collection of the Museo de La Amblyraja doellojuradoi (Pozzi, 1935), Bathyraja Plata (MLP-Cr), La Plata, Argentina. magellanica (Philippi, 1902) and Atlantoraja castelnaui (Miranda Ribeiro, 1907) were caught during research cruises of the Instituto Nacional RESULTS de Investigación y Desarrollo Pesquero (INIDEP) Bathyraja scaphiops was the only rajiform at similar and/or higher latitudes during 2011, species parasitized by Dendrapta. 2012 and 2013. Subclass COPEPODA Milne Edwards, 1840; The prevalence and mean intensity were Order SIPHONOSTOMATOIDA Thorell, 1859; calculated following Bush et al. (1997). Sterne’s Family LERNAEOPODIDAE Milne Edwards, 1840; exact 95% confidence limits (CL) were calculated Genus Dendrapta Kabata, 1964. for prevalence using Quantitative Parasitology 3.0 software (QP3.0) (Reiczigel & Rózsa 2001, Dendrapta nasicola n. sp. Reiczigel 2003). Skates were examined fresh or kept frozen Adult female [based on 15 ovigerous specimens, at –20°C until examination. Olfactory sacs were including holotype, 10 paratypes and four excised and examined using a stereo microscope. additional specimens used for dissection and In order to isolate copepods from host tissues, SEM]. Total body length (excluding posterior the entire attachment section was removed and processes) 11.1±1 (9.7–12.8, 15). Cephalothorax the host remaining tissues, surrounding the heart-shaped, 2.9±0.4 (2.3–3.7, 15) long, 3.2±0.3 holdfast, were degraded by enzymatic digestion (2.9–3.8, 15) maximum width, slightly tilted with pepsin. Fifteen female copepods were fixed ventrally to long axis of trunk (Figs. 1a, b; 2a, b), its in 4% formalin for storage before being studied posterior part fully occupied by maxillary basis and measured. Two specimens were cleared (Figs. 2b; 3a), dorsal shield indistinct. Buccal in lactic acid; appendages were dissected cone situated anteriorly on ventral surface of and examined using a light microscope. cephalothorax (Figs. 2b; 3b). Trunk 8.3±1.1 (6.1– Measurements are indicated in millimetres as 9.6, 15) long, 5.8±0.5 (5.2–6.8, 15) maximum width, mean ± standard deviation, with ranges and with short anterior part (neck), 1.6±0.2 (1.4–2.0, 12) number of specimens measured in parentheses. long part separated by shallow constriction from Anatomical terminology followed Boxshall roughly pyriform posterior part, 6.7±0.9 (4.7–7.7, & Halsey (2004), terminology of appendages 15) long (Figs. 1a, b; 2a). Abdomen small, rather armature and segmentation follows Kabata dorsal. Paired posterior processes situated on (1979). both sides of abdomen, club-shaped, 6.7±1.0 (5.3–8.9, 27) long, representing 81.0% (62.2–102.4) An Acad Bras Cienc (2020) 92(Suppl. 2) e20180933 2 | 8 MANUEL M. IRIGOITIA, VERÓNICA TAGLIORETTI & JUAN T. TIMI Dendrapta nasicola N. SP. Table I. Composition of samples of 21 skate species in the Argentine Sea and population descriptors of Dendrapta nasicola n. sp. Host species Common name N P MA Amblyraja doellojuradoi (Pozzi, 1935) southern thorny skate 52 0 0 Atlantoraja castelnaui (Miranda Ribeiro, 1907) spotback skate 31 0 0 Atlantoraja cyclophora (Regan 1903) eyespot skate 65 0 0 Atlantoraja platana (Günther 1880) La Plata skate 3 0 0 Bathyraja albomaculata (Norman 1937) spotted skate 42 0 0 Bathyraja brachyurops (Fowler, 1910) broadnose skate 31 0 0 Bathyraja griseocauda (Norman 1937) graytail skate 29 0 0 Bathyraja macloviana (Norman 1937) Patagonian skate 32 0 0 Bathyraja magellanica (Philippi 1902) Magellan skate 18 0 0 Bathyraja multispinis (Norman 1937) multispine skate 1 0 0 63.2 1.6 Bathyraja scaphiops (Norman 1937) cuphead skate 19 (39.2-82.4) (0.9-2.6) Dipturus brevicaudatus (Marini 1933) yellownose skate 95 0 0 Psammobatis bergi Marini 1932 blotched sand skate 31 0 0 Psammobatis extenta (Garman 1913) zipper sand skate 36 0 0 Psammobatis lentiginosa McEachran 1983 freckled sand skate 2 0 0 Psammobatis rudis Günther 1870 smallthorn sand skate 41 0 0 Psammobatis rutrum Jordan 1891 spade sand skate 2 0 0 Psammobatis normani McEachran, 1983 shortfin sand skate 35 0 0 Rioraja agassizii (Müller & Henle 1841) Rio skate 41 0 0 Sympterygia acuta Garman 1877 bignose fanskate 65 0 0 Sympterygia bonapartii Müller & Henle, 1841 smallnose fanskate 192 0 0 N: number of examined fish; P: prevalence; MA: mean abundance. Sterne´s exact 95% confidence limits are given between parentheses after P and MA values. of trunk length, dorsal to multiseriate egg sacs, two-segmented, first segment with ventral patch 8.5±1.6 (4.9–10.7, 20) long, 2.4±0.3 (1.8–2.8, 20) of spinules, distal segment armed with robust wide (Figs. 1a, b; 2a, c). curved hook 1, slender seta 2, and process 5 Antennule (Fig. 1c) three-segmented, first located on spinulose process 4 on distoventral segment carrying short dorso-median whip; margin; process 3 absent. Mouth cone small, second segment short, carrying small distal labrum and labium fringed by setules (Figs. solus, terminal segment with rounded tip, 3b, c, d); mandible (Fig. 1d) represented by bearing three subterminal tubercles (processes narrow blade with three secondary teeth; dental 1-3), digitiform aesthete (4), and two short setae formula: P1, S1, P1, S1, P1, S1, B5. Maxillule (Figs. (5 and 6) (armature formula -base to apex- as 1f; 3f) bilobate, exopod cylindrical ending in follows: 1, 1, 5 + 1 aesthete). Antenna (Figs. 1e; two subequal setae; endopod longer, with 3b, c, e) biramous, basis with a distoventral three terminal papillae and proximal patch of patch of spinules, rami subequally long; exopod spinules. Maxilla (Figs. 1a; 2a; 3g) developed as 1-segmented with spinulose lateral and distal a profusely branched holdfast characteristic of margins, bearing two short setae (one lateral the genus, basal part robust (Figs. 2b, c), 4.1±0.9 and one medial) near distal end; endopod (2.2–5.4, 26) long, 1.5±0.3 (0.7–2.1, 26), narrowing An Acad Bras Cienc (2020) 92(Suppl. 2) e20180933 3 | 8 MANUEL M. IRIGOITIA, VERÓNICA TAGLIORETTI & JUAN T. TIMI Dendrapta nasicola N. SP. Figure. 1 Dendrapta nasicola n. sp. (adult female) from Bathyraja scaphiops (Arhynchobatidae). a general habitus (lateral view), composite drawing. b general habitus (ventral view) c antennule.