Mastigodiaptomus galapagoensis n. sp. (Crustacea: Copepoda: Diaptomidae), a possibly extinct copepod from a crater lake of the Galápagos archipelago.

Background: A new species of a Neotropical diaptomid copepod is described based on individuals recovered from a small, almost forgotten collection of unique plankton samples from El Junco, a crater lake in San Cristóbal island, Galápagos archipelago. This copepod was regularly reported (1966-2004) as an abundant zooplankter in the lake, but it was not found in subsequent plankton surveys (2007-2018), and its specific identity remained unknown. In 2020, it was declared extinct because of introduced fish predation, rotenone treatment, and other major disturbances. The taxonomic examination of these invaluable specimens allowed us to recognize them as representing an undescribed species of the freshwater diaptomid genus Mastigodiaptomus Light, 1939. Methods: Here, we describe the new species from El Junco crater lake, located in the San Cristóbal island a part of the Galápagos archipelago, collected with plankton nets. The description is based on detailed morphology, based on SEM and light microscopy. Results: The taxonomic examination of these invaluable specimens allowed us to recognize them as representing an undescribed species of the freshwater diaptomid genus Mastigodiaptomus Light, 1939. The new species was readily assigned to this genus and is distinguished from its known congeners by details of (1) the male right fifth leg terminal claw and aculeus, (2) spiniform processes pattern of the right geniculate antennule segments 10-16, (3) length and structure of the spiniform process of the antepenultimate segment of the male right antennule, and (4) details of the dorsal process on the female fourth pediger. This finding represents the first report of this Neotropical copepod genus outside its original biogeographic region, the third species of a diaptomid copepod reported from insular freshwater systems, the southernmost record of Mastigodiaptomus, and the only freshwater calanoid in the Galápagos. The intriguing presence of this chiefly Neotropical copepod genus here could be related either to (1) human agency linked to pirate activities, commercial travelling by Spaniard ships, whaling activities, and intense tortoise hunting in San Cristóbal island. In the past, El Junco was the only freshwater source 600 nautical miles around, or (2) zoochory of resistant dormant stages passively transported by more than 65 migrating bird species known to settle in San Cristóbal. These two hypotheses cannot be properly tested at this time, so the explanation of the presence of this copepod will remain as a new open question in the fascinating natural history of the Galápagos.

New records of Harpacticoids (Crustacea, Copepoda) from a coastal system of northern Colombia

Three species of harpacticoids are herein recorded from the zooplankton of Rodadero beach, Santa Marta, Magdalena, Colombia. Samples were collected from the littoral zone, mainly at inshore areas covered by mangrove vegetation and in an adjacent oyster bank. One of them, Laophonte cornuta Philippi, 1840 is new to the Colombian harpacticoid fauna, the other two species: Distioculus minor (Scott T., 1894) and Microsetella norvegica (Boeck, 1865) are new reports to the Magdalena department. This is the first illustrated record confirming their presence in Colombia and Magdalena, northern Colombia. Comparative morphological comments and illustrations of these species are also provided to document this report.

Se registran tres especies de harpacticoides en el zooplancton de playa Rodadero, Santa Marta, Magdalena, norte de Colombia. Se recolectaron muestras en la zona litoral, principalmente en áreas costeras de manglar y en un banco de ostras. Una de ellas, Laophonte cornuta Philippi, 1840 es nueva para la fauna de harpacticoides de Colombia; las otras dos especies: Distioculus minor (Scott T., 1894) y Microsetella norvegica (Boeck 1865) son nuevos reportes para el departamento del Magdalena. Este es el primer registro ilustrado que confirma su presencia en Colombia y Magdalena. Se proporcionan comentarios morfológicos comparativos e ilustraciones de estas especies.

A new Cardiodectes Wilson, 1917 (Hexanauplia: Copepoda: Siphonostomatoida) parasitic on a scarid teleost (Perciformes: Scaridae) from Roatan Island, Central America.

Members of the parasitic copepod family Pennellidae are highly transformed ecto- or mesoparasites infecting a wide array of marine teleosts. Currently, this family contains more than 20 valid genera. The pennellid genus Cardiodectes Wilson, 1917 is currently known to contain 15 nominal species. Some pennellids exhibit a complex life cycle involving an intermediate host; it is known that planktonic pteropod molluscs are intermediate hosts for Cardiodectes. Pennellid mesoparasites can be detected by the conspicuous female egg-carrying trunk on the host external surface. The copepod cephalothorax is deeply embedded in the host muscle tissue. Members of Cardiodectes have been reported from several teleost families, mainly Myctophidae and Engraulidae. From the parasitological examination of a juvenile individual of a scarid teleost collected in a reef lagoon of Roatan Island, Honduras, Central America, several ovigerous female individuals of a mesoparasitic pennellid copepod were found; these specimens were recognized as representative of an undescribed species of Cardiodectes Wilson, 1917. The new species, C. roatanensis n. sp., differs from its known congeners in several respects, including the presence of neck lobes, paired posterior protuberances of the trunk, trunk shape and proportions, structure of cephalothorax lobes, cephalothorax relative size, and number of legs. The new species from Roatan is the second member of this copepod genus to be reported from the Caribbean region, after C. boxshalli Bellwood, 1981 from off Jamaica (Bellwood 1981). It is also the second report of Cardiodectes on a parrotfish.

A new species of Monstrilla (Copepoda, Monstrilloida) from the western Caribbean with comments on M.wandelii Stephensen, 1913 and M.conjunctiva Giesbrecht, 1893.

The taxonomic study of monstrilloid copepods is hampered by incomplete early descriptions, uncertain synonymies, and the difficulty of reliably matching males and females of species. A re-evaluation of male monstrilloid specimens collected from two reef areas of the Mexican Caribbean allowed me to clarify the status of Monstrillamariaeugeniae Suárez-Morales & Islas-Landeros, 1993 and M.wandelii Stephensen, 1913 based on a comparison of males attributed to each of these species. Males from the Puerto Morelos reef system, northern Mexican Caribbean coast, were first proposed as a tropical subspecies of the subarctic M.wandelii; later on, morphologically close males collected from the Mahahual reef area, southern Mexican Caribbean coast, were designated as the males of M.mariaeugeniae. Their status is here corrected with the description of M.mahahualensis sp. nov. based on the Mahahual males; the new species shares the same type of genitalia with the antarctic M.conjunctiva Giesbrecht, 1892 and the subarctic M.wandelii; Park (1967) linked a single male from Vancouver to M.wandelii. It was realised that Park's (1967) males from the Vancouver area and the two Mexican Caribbean groups of males represent different, undescribed species. I here reassign the males earlier attributed to M.mariaeugeniae as a new species of Monstrilla which is herein described. The new species differs from the males of M.conjunctiva and M.wandelii by details of the genitalia, length of the setae of the fifth legs, armature and integumental structures of the antennules, and size of the outer exopodal spines of legs 1-4. This is the third known species of Monstrilla with a M.conjunctiva-like male genitalia and the first one known from tropical areas. The male of both M.mariaeugeniae and M.wandelii remain unknown.

A new species of Nitokra Boeck, 1865 (Copepoda, Harpacticoida, Ameiridae) from the Caribbean coast of Colombia.

Biological samples obtained from a coastal system of northern Colombia yielded male and female specimens of an undescribed harpacticoid copepod of the diverse ameirid genus Nitokra Boeck, 1865. The new species is a member of the genus group III. We describe the new species based on adult male and female individuals. Nitokrapuebloviejensis sp. nov., appears to be most closely related to N.vietnamensis Tran & Chang, 2012, but they can be separated by the following characters: 1) number of setal elements on second segment of mandibular palp, 2) P1ENP/EXP ratio, 3) relative lengths of P2, P3ENP/EXP, 4) number of elements on male P5EXP and ENP, and 5) segmentation of male antennule. In addition, N.puebloviejensis sp. nov. can be confused with two other congeners: N.taylori Gómez, Carrasco & Morales-Serna, 2012 from South Africa and Colombia and N.kastjanensis Kornev & Chertoprud, 2008 from the White Sea, but the new species can be distinguished from them by: 1) number of setae on the maxillule coxa, 2) P1ENP/EXP ratio, 3) P2,P3ENP/EXP ratio, 4) female and male P5 setophore, 5) setation pattern of female P5EXP and ENP, 6) structure of female P6, 7) ornamentation of female anal operculum, 8) number of setae on male P5EXP, and 9) the male antennule segmentation. Most importantly, the presence of a group of five short setae on the medial surface of the maxilliped syncoxa allows the new species to be readily distinguished from its congeners. Only two subspecies and one species of this genus have been hitherto recorded from Colombia. A key to the 23 known American species of Nitokra is provided.

A new species of Esola Edwards, 1891 (Crustacea, Copepoda, Harpacticoida, Laophontidae) from the Caribbean coast of Colombia.

A new species of the harpacticoid copepod genus Esola is described from specimens collected in Rodadero Beach, on Gaira Bay, on the Caribbean coast of Colombia. The species, E.wellsi sp. nov., is described, illustrated, and com-pared with its congeners. Esolawellsi sp. nov. differs from its known congeners in details of the armature of legs 1-4. It most closely resembles E.bulbifera (Norman, 1911) in the armature formula of P1-P5 but differs from the latter in several respects, including the female antennule segmentation (7-segmented in E.bulbifera but distinctly 6-segmented in E.wellsi sp. nov.) and in the shape and size of the male P3ENP2 apophysis, among other characters. This is the second species of the genus known from the Caribbean and the second record of Esola in the Northwestern Tropical Atlantic. The genus now contains eight species. A key to the known species of the genus is also included.

First record of the freshwater copepod Mesocyclops paranaensis Dussart & Frutos, 1986 (Copepoda: Cyclopoida: Cyclopidae) from Colombia / Primer registro del copépodo de aguadulce Mesocyclops paranaensis Dussart& Frutos, 1986 (Copepoda: Cyclopoida: Cyclopidae) de Colombia

Abstract The Neotropical free-living freshwater cyclopoid copepod Mesocyclops paranaensis Dussart & Frutos, 1986 was found in a small temporal pond in La Guajira, northern Colombia. Hitherto, it has been reported from Argentina, Paraguay, and Brazil. This is the first record of this species in Colombia, its northernmost finding in South America, and the fourth locality in which this species has been recorded from. Mesocyclops paranaensis can be distinguished from its closest congeners by a unique combination of the characters of the female, including: 1) leg 4 intercoxal sclerite with two large, acute projections; 2) P3, P4 intercoxal sclerite caudal surface lightly pilose; 3) seminal receptacle with narrow lateral arms and weakly convex anterior margin; 4) second antennary endopodite with seven setae, and insertion of antennary exopodal seta with adjacent spinules; 5)frontal surface of P1 basipodite ornamented with long spinules; 6) posterior margin of anal somite with continuous row of spinules; and 7) inner margin of caudal ramus hirsute. The Colombian population shows some subtle morphological differences with respect to previous reports.

Resumen El copépodo ciclopoide de agua dulce Mesocyclops paranaensis Dussart & Frutos, 1986 fue encontrado en un pequeño estanque temporal al norte de La Guajira. Hasta ahora, esta especie había sido registrada en Paraguay, Argentina y Brasil. Este es el primer registro de esta especie sudamericana en Colombia, su registro más septentrional en América del Sur, y la cuarta localidad en la que se registra. Mesocyclops paranaensis se puede distinguir de sus congéneres más cercanos por una combinación única de caracteres que incluyen: 1) esclerito intercoxal de la pata 4 con dos grandes proyecciones puntiagudas, 2) esclerito intercoxal de la pata 3 y pata 4 ligeramente piloso, 3) receptáculo seminal con brazos laterales estrechos y margen anterior débilmente convexo, 4)segundo segmento endopodal de la antena con siete setas, inserción de la seta exopodal de la antena con espínulas, 5) superficie frontal del basipodito de la pata 1 ornamentada con largas espínulas, 6) posterior margen del somita anal de la hembra con hileras continuas de espínulas y 7) margen interno de la rama caudal pilosa. Se proporciona una breve descripción de esta especie e ilustraciones de la población colombiana y se compara con su congénere más cercano. Los especímenes de Colombia muestran algunas diferencias morfológicas con respecto a los reportes previos acerca de esta especie.

A new Bradophila Marchenkov, 2002 (Copepoda, Cyclopoida, Bradophilidae) parasitic on a flabelligerid polychaete from the Chukchi Sea.

The cyclopoid copepod family Bradophilidae includes a few species of mesoparasitic copepods infecting flabelligerid polychaetes. It contains two species of Bradophila Levinsen, 1878, the type genus: B. pygmaea Levinsen, 1878 and B. minuta Boxshall, O'Reilly, Sikorski & Summerfield, 2019, both known from North Europe. Two other genera (i.e., Trophoniphila M'Intosh, 1885 and Flabellicola Gravier, 1918) have some affinities with this family including their host preference. Mesoparasitic copepods are highly specialized, morphologically reduced forms. Part of their body (endosoma) is partially lodged in the host body and the other part is external (ectosoma); both parts are connected by an intersomital stalk. Infection by these copepods can be readily detected by the presence of the egg-carrying ectosoma on the host external surface. From the analysis of flabelligerid polychaetes collected in 2012 from the Chukchi Sea, two ovigerous female individuals of a bradophilid copepod were recorded. These specimens were recognized as representative of an undescribed species of Bradophila. The new species, B. susanae n. sp., shows the generic diagnostic characters and differs from its two other known congeners in several respects, including the cuticular ectosomal ornamentation, body proportions, size of the intersomital stalk, position of the genital pore, and shape and arrangement of egg sacs. Also, the new species ectosomal size range (0.440 - 0.450 µm) falls between the size range of its two known congeners. Our finding expands the known host range of bradophilid copepods to include a new flabelligerid host, Bradabyssa nuda (Annenkova-Chlopina) from the Russsian Arctic region.

Validation of Cymbasoma turcorum and Monstrillopsis pontoeuxinensis, two monstrilloids from Turkey described by Suárez-Morales amp; Üstün in 2018 (Crustacea: Copepoda: Monstrilloida).

Recently, Suárez-Morales Üstün (2018) described two new species of monstrilloid copepods, Cymbasoma turcorum and Monstrillopsis pontoeuxinensis from Turkish coastal waters of the Black Sea. The morphological descriptions, illustrations, and type designations presented in that paper fully characterized both new species; however, the journal issue in which the description appeared was published only online, with no print version (Suárez-Morales Üstün 2018), and the article in which these new names were introduced did not include a ZooBank registration number (LSID) for the article or any other evidence of such registration. This is currently required by Article 8.5 of the International Code of Zoological Nomenclature for an electronic work to be deemed "published" under the Code (International Commission on Zoological Nomenclature 2012). Inasmuch as Suárez-Morales Üstün (2018) is an "unpublished work", the specific names turcorum and pontoeuxinensis proposed in it are unavailable. The present note is intended to fully validate these two names by proposing them once again as new while also fulfilling all of the Code's current conditions for nomenclatural availability of this work itself and the two new names. The date and authorship of these two specific names will, accordingly, be those of this note, not Suárez-Morales Üstün (2018).

Discovery of the fish host of the 'planktonic' caligid Caligus undulatus Shen & Li, 1959 (Crustacea: Copepoda: Siphonostomatoida).

The siphonostomatoid copepod Caligus undulatus Shen & Li, 1959 has been widely reported from plankton samples obtained from neritic and oceanic waters off coasts of the Indo-West Pacific and Atlantic Oceans. Until now, its fish host has remained unknown. This copepod belongs to an intriguing group of congeners that, despite being part of a chiefly parasitic group, are consistently found as zooplankters. Quite unexpectedly, in October 2019, a fish host of C. undulatus was discovered in the Seto Inland Sea, Japan-namely, the Japanese sardinella Sardinella zunasi (Bleeker, 1854). Both juvenile (chalimus) and adult individuals of this caligid were observed as parasites of the fish host. The discovery suggests that the species has an alternative life cycle as previously proposed for other purportedly 'planktonic' congeners and might frequently switch hosts during the adult stage. Thus, the C. undulatus group is newly proposed as a species group in the genus, in which five species are known as planktonic. Some hypotheses on the modified life cycle of caligids also briefly discussed.

The 2015-2016 El Niño increased infection parameters of copepods on Eastern Tropical Pacific dolphinfish populations.

The oceanographic conditions of the Pacific Ocean are largely modified by El Niño (EN), affecting several ecological processes. Parasites and other marine organisms respond to environmental variation, but the influence of the EN cycle on the seasonal variation of parasitic copepods has not been yet evaluated. We analysed the relation between infection parameters (prevalence and mean intensity) of the widespread parasitic copepods Caligus bonito and Charopinopsis quaternia in the dolphinfish Coryphaena hippurus and oceanography during the strong 2015-16 EN. Fish were collected from capture fisheries on the Ecuadorian coast (Tropical Eastern Pacific) over a 2-year period. Variations of sea surface temperature (SST), salinity, chlorophyll a (Chl-a), Oceanic Niño Index (ONI), total host length (TL) and monthly infection parameters of both copepod species were analysed using time series and cross-correlations. We used the generalised additive models for determine the relationship between environmental variables and infection parameters. The total body length of the ovigerous females and the length of the eggs of C. bonito were measured in both periods. Infection parameters of both C. bonito and Ch. quaternia showed seasonal and annual patterns associated with the variation of environmental variables examined (SST, salinity, Chl-a and ONI 1+2). Infection parameters of both copepod species were significantly correlated with ONI 1+2, SST, TL and Chl-a throughout the GAMLSS model, and the explained deviance contribution ranged from 16%-36%. Our results suggest than an anomaly higher than +0.5°C triggers a risen in infection parameters of both parasitic copepods. This risen could be related to increases in egg length, female numbers and the total length of the ovigerous females in EN period. This study provides the first evidence showing that tropical parasitic copepods are sensitive to the influence of EN event, especially from SST variations. The observed behaviour of parasitic copepods likely affects the host populations and structure of the marine ecosystem at different scales.

A NEW SPECIES OF Halicyclops (Copepoda, Cyclopoida, Halicyclopinae) FROM AN ESTUARINE SYSTEM OF THE CARIBBEAN COAST OF COLOMBIA / Una nueva especie de Halicyclops (Copepoda, Cyclopoida, Halicyclopinae) de un sistema estuarino de la Costa Caribe de Colombia

ABSTRACT Plankton samples obtained from the Ciénaga Grande de Santa Marta, an extensive estuarine system in northern Colombia, yielded adult male and female specimens of an undescribed halicyclopine cyclopid copepod of the genus Halicyclops. Cyclopid copepods are frequently found in freshwater and transitional habitats. Members of the subfamily Halicyclopinae are chiefly brackish water forms with a few freshwater species. The new species described herein is assignable to the group of species "F" of Halicyclops (sensu Pesce, 2018) with a 2333 exopodal spine formula. Currently, this group contains five species and one subspecies. Halicyclopsgutierrezi sp. n. can be distinguished from its known congeners by the absence of an anal operculum, the relative length of setae of the female and male P5, the relative length of the inner setae of P4EXP3, and details of the male antennule. This is the fifth species of Halicyclops recorded from Colombia and the first one of Halicyclops group "F" described from the Caribbean region. With the addition of H. gutierrezi sp. n., the number of species of the genus known from the Neotropics increased to 20. A key to the species of the genus recorded in Colombia is also provided.

RESUMEN Muestras de plancton obtenidas de la Ciénaga Grande de Santa Marta, un extenso sistema estuarino en el norte de Colombia, produjeron especímenes machos y hembras de una especie no descrita del género Halicyclops. Los copépodos de la familia Cyclopidae son dominantes en los hábitats de agua dulce y transicionales. Los miembros de la subfamilia Halicyclopinae son predominantemente de hábitats salobres, con algunas especies de agua dulce. La nueva especie aquí descrita es asignable al grupo de especies denominado "F" de Halicyclops (sensu Pesce, 2018) con una fórmula de espinas exopodales (P1-4) = 2333. Actualmente, este grupo contiene cinco especies y una subespecie. Halicyclops gutierrezi sp. n. puede distinguirse de sus congéneres conocidos por la ausencia de un verdadero opérculo anal, la longitud relativa de las setas de la P5 de la hembra y del macho, la longitud relativa de las setas internas de P4EXP3 y por detalles de la anténula del macho. Esta es la quinta especie de Halicyclops registrada en Colombia y la primera del grupo "F" de Halicyclops descrita en la cuenca del Caribe. Con la adición de H. gutierrezi sp. n., aumentó a 20 el número de especies del género que se conocen en la región Neotropical. Se proporciona una clave para la identificación de las especies del género registradas en Colombia.

A new species of Monstrilla (Copepoda, Monstrilloida) from the plankton of a large coastal system of the northwestern Caribbean with a key to species.

The genus Monstrilla Dana, 1849 is the most diverse of the copepod order Monstrilloida. Monstrilloid copepods are endoparasites of benthic polychaetes and molluscs; adult individuals are free-living, non-feeding reproductive forms that briefly become part of the zooplankton community, where they are occasionally captured by plankton nets. Monstrilloid copepods are frequently found during routine plankton samplings of coastal and estuarine habitats, but they are rarely found in large numbers. The western sector of the Caribbean Sea is known to harbor a diverse monstrilloid fauna. The analysis of zooplankton samples obtained during nine years from Chetumal Bay, a large embayment of the Mexican Caribbean coast, yielded a male monstrilloid that was found to represent a new species. It is herein described following upgraded standards and compared with its congeners. A key to males and females of the Monstrilla species known from the northwestern Caribbean is also provided.

Recognition and partial solution of nomenclatural issues involving copepods of the family Monstrillidae (Crustacea: Copepoda: Monstrilloida).

This work seeks to expose and clear up nomenclatural irregularities involving copepods of the order Monstrilloida, family Monstrillidae. The diagnostic text related to Monstrilla minuta Isaac, 1974 and four nominal species of Thaumaleus Krøyer, 1849 (now Cymbasoma Thompson, 1888) proposed by Isaac in 1974 is sufficient for all names to be available from their original description except for Thaumaleus similirostratus, which was proposed conditionally in 1974 and was first made available by Isaac in 1975; "similirostris" as used by Grygier in 1995 is an incorrect subsequent spelling. Four other specific names proposed in 1975 by Isaac, but disclaimed by him as nomina nuda (an action permitted retroactively by the Fourth Edition of the International Code of Zoological Nomenclature) have never been made available. By quoting the necessary information from Isaac's doctoral dissertation, two of them are validated herein under the names Thaumaleus frondipes Isaac in Grygier Suárez-Morales, sp. nov., and Strilloma scotti Isaac in Grygier Suárez-Morales, sp. nov., and are immediately reassigned as new combinations to Cymbasoma and Monstrilla Dana, 1849, respectively. A fifth such name, Thaumaleus tumorifrons, has already been made available under the authorship of Suárez-Morales, 1999, but its females are excluded from the type series; the spelling of the specific name of the new species recently proposed for those females, Cymbasoma mediterranea Suárez-Morales, Goruppi, Olazabal Tirelli, 2017, is emended to mediterraneum to match the gender of the genus. For Cymbasoma bowmani Suárez-Morales Gasca, 1998, the "Form B" female mentioned in the original description is excluded from the type series. The authorship and date of availability of Haemocera (currently Cymbasoma) morii depends on which language version of Article 13.1.1 of the Code is followed; a ruling by the International Commission on Zoological Nomenclature under Article 87 of the Code is necessary to resolve the matter. The composition of the type series of Cymbasoma bullatum (Scott, 1909) in terms of both number and sex has become unclear; its type locality is restricted herein to the vicinity of Obi Island in the Moluccas. Despite a published statement to the contrary, the syntype series of Cymbasoma germanicum (Timm, 1893) included specimens from other localities than just Helgoland. The type series of Cymbasoma guerrerense Suárez-Morales Morales-Ramírez, 2009 consists only of the holotype, which was mistakenly reported under the wrong registration number. The supposed invalidity of Monstrilla capitellicola Hartman, 1961 is discussed. Monstrilla javensis Isaac, 1974, nomen nudum, has remained unavailable owing to lack of adherence to Article 16.1 of the Code by later authors; the specific name is made available herein, under Suárez-Morales' authorship, in the combination Cymbasoma javense sp. nov. The taxonomic (and eventual nomenclatural) question of the status of M. mariaeugeniae Suárez-Morales Islas-Landeros, 1993 vis à vis M. wandelii Stephensen, 1913, i.e. as a separate species or a subspecies of the latter, remains unsettled. Cymbasoma lenticula Suárez-Morales McKinnon, 2014 and Monstrillopsis boonwurrungorum Suárez-Morales McKinnon, 2014 are fixed herein as the correct original spellings of those two specific names. Resolution of the problem posed by assignment of the specific name reticulata to supposedly non-conspecific males and females in the genus Monstrillopsis Sars, 1921 requires the designation of a neotype by the International Commission on Zoological Nomenclature.

A new species of Pupulina van Beneden, 1892 (Copepoda, Siphonostomatoida, Caligidae) from Aetobatuscf.narinari (Pisces, Myliobatidae) from the Pacific coast of Ecuador.

A new caligid copepod species, Pupulinamantensissp. n. is described based on female and male specimens collected from the gills of the myliobatid elasmobranch Aetobatuscf.narinari Euphrasen, 1790 captured off the Pacific coast of Ecuador. The new species has a unique combination of characters that diverges from its known congeners, including: (i) weakly developed posterolateral processes on the genital complex; (ii) large spines on posterior surface of maxilliped basis (iii) abdomen slender, unsegmented, approximately 1/2 length and 1/5 width of genital complex; (iv) third exopodal segment of leg II with single long naked spine adjacent to minute, naked lateral spine; (v) velum of leg II with adjacent patch of denticles; (vi) caudal rami slightly less than half the length of genital complex; (vii) post-antennal process with robust, posteriorly directed tine, sclerotized stump posterolaterally, and two multi-sensillate papillae located on or near base of process (viii) post-oral process oval. The overall prevalence of P.mantensissp. n. on its host was 37.5% and its mean abundance was 1.87 specimens per host. This is the second record of the genus Pupulina from Ecuador and the second record of Pupulina infecting rays of the Myliobatinae genus Aetobatus, of the subfamily Myliobatinae, after its discovery on A.ocellatus in Australia, thus confirming this expansion of its previously known host range to a new elasmobranch subfamily.

Notes on Halicyclops (Copepoda, Cyclopoida, Cyclopidae) from Colombia and the western Caribbean: a new record with a key to species of Group "B" sensu Rocha (1991) / Notas sobre Halicyclops (Copepoda, Cyclopoida, Cyclopidae) de Colombia y el Caribe occidental: un nuevo registro con una clave para las especies del Grupo "B" sensu Rocha (1991)

Three species of brackish waters microcrustaceans are herein recorded; they belong to the cyclopoid copepod genus Halicyclops and were collected from a coastal system in northern Colombia: H. exiguus Kiefer, 1934,H. venezuelaensis Lindberg, 1954, and H. hurlberti Rocha, 1991. The former has intraspecific variations that deserve further study. The finding of the latter species, previously known from the Eastern Tropical Pacific, represents a new record for Colombia and the Caribbean Sea Basin in the Northwestern Tropical Atlantic. With the finding of H. hurlberti the number of species of Halicyclops known from the Neotropical region and Colombia increases to 20 and 5, respectively. The regional diversity of the genus is probably underestimated. A key to species of the genus belonging to group "B" sensu Rocha (1991) is also provided.

Se registran tres especies de microcrustáceos de aguas salobres; son copépodos ciclopoides del género Halicyclops procedentes de un sistema costero en el norte de Colombia: H. exiguus Kiefer, 1934, H. venezuelaensis Lindberg, 1954 y H. hurlberti Rocha, 1991. La primera especie tiene una variación intraespecífica que merece estudios más profundos. El hallazgo de la última especie es conocida sólo en el Pacífico Tropical Oriental, representa un registro nuevo para Colombia y la cuenca del Mar Caribe en el Atlántico tropical noroccidental. Con el hallazgo de H. hurlberti, la cantidad de especies de Halicyclops reconocidas en la región Neotropical y Colombia aumenta a 20 y 5, respectivamente. La diversidad regional del género probablemente está subestimada. Se proporciona una clave para las especies del género que pertenecen al grupo "B" sensu Rocha (1991).

A new species of Monstrillopsis (Crustacea, Copepoda, Monstrilloida) from the lower Northwest Passage of the Canadian Arctic.

A new species of monstrilloid copepod, Monstrillopsis planifronssp. n., is described from an adult female that was collected beneath snow-covered sea ice during the 2014 Ice Covered Ecosystem - CAMbridge bay Process Study (ICE-CAMPS) in Dease Strait of the Canadian Arctic Archipelago. Currently, up to six species of this order are known to occur in polar latitudes. The new species described herein shares similarities with Monstrillopsis dubia (Scott, 1904) but differs in its body proportions and cephalothorax ornamentation; the cephalothorax is covered by minute scattered papillae on dorsal and ventral surfaces; this species has a reduced fifth leg endopod, fifth leg exopod armed with three setae, antennule with fused segments 3-4, and the genital double-somite bears unique posterolateral processes. This is the second species of this genus recorded in the Arctic, after Monstrillopsis ferrarii (Suárez-Morales & Ivanenko, 2004), described from the White Sea, and is the first record of Monstrillopsis in Canadian waters. With the addition of this new species and the recognition of Monstrillopsis bernardensis comb. nov. as a member of this genus, the number of nominal species is now 15. Overall, this genus has a tendency to be distributed in temperate and cold waters, while only three species have been found in tropical and subtropical latitudes.

A new anchialine Stephos Scott from the Yucatan Peninsula with notes on the biogeography and diversity of the genus (Copepoda, Calanoida, Stephidae).

Surveys of the anchialine crustacean fauna of the Yucatan Peninsula (YP), Mexico, have revealed the occurrence of calanoid copepods. The genus Stephos Scott, 1892, belonging to the family Stephidae is among the most frequent and widely distributed groups in anchialine caves but has not been hitherto recorded from the YP. Recent collections from an anchialine cave in an island off the northern coast of the YP yielded many specimens of a new species of Stephos. The new taxon, S. fernandoisp. n., is described here based on male and female specimens. The new species is clearly distinguished from its congeners by the following characters: male left fifth leg with three terminal lamellae plus subdistal process, right leg with distal row of peg-like elements; female fifth leg with single long, acute apical process; genital double-somite with two rows each of 4 long spinules adjacent to operculum; legs 2-4 with articulated setae. The diversity of the genus shows regional differences; the Australia-Western Pacific region is the most diverse (eleven species), followed by the Mediterranean (seven species) and the Northeastern Atlantic (six species); only four species are known from the Northwestern Tropical Atlantic (NWTA). The morphology of the female fifth leg was examined to explore possible biogeographic trends in the genus; patterns suggest multiple colonization events in the highly diverse regions and a relatively recent radiation in the NWTA, characterized by anchialine forms. The introduction of stephid copepods in the region may be a relatively recent event derived from colonization of benthopelagic ancestral forms and subsequent invasion onto cave habitats. The new species appears to be linked to the strictly anchialine Miostephos.

COMPLEMENTARY DESCRIPTION AND RECORD OF Neocyclops ferrarii (Cyclopidae: Halicyclopinae) FROM NORTHERN COLOMBIA / Descripción complementaria y registro de Neocyclops ferrarii (Cyclopidae: Halicyclopinae) en el norte de Colombia

ABSTRACT The interstitial cyclopoid copepod Neocyclops ferrarii Rocha, 1995 was found in samples obtained from littoral areas of Rodadero Bay, northern Colombia. The specimens from Colombia share the diagnostic features of N. ferrarii presented in the original description. However, the Colombian specimens show some degree of variation with respect to the type material in: 1) the number of teeth in the labrum; 2) the length of outer exopodal spine on female leg 5; 3) the relative length of the mandibular palp setae; 4) length/width ratio of caudal rami; 5) the length ratio of caudal setae VI/III; 6) the length ratio of caudal setae VII/VI; 7) the male body size; 8) the male caudal rami length/width ratio; 9) This is the second record of this species after its original description from Belizean waters. In the Caribbean region N. ferrarii most closely resembles N. vicinus Herbst, both of them bear an antennary exopod, a 12-segmented female antennule, P3ENP3 armature formula 3,III, but can be separated from the latter by difference in the length/width ratio of the female caudal ramus, the length ratio of caudal setae VI/III, the length ratio of caudal setae VII/VI, the male body size, the number of segment of P4ENP, the armature details of mandibular palp and the number of segments of male P5. This is the second species of Neocyclops recorded from Colombia and represents a distributional range expansion of N. ferrarii in the Caribbean Basin.

RESUMEN El copépodo ciclopoide intersticial Neocyclops ferrarii Rocha, 1995 fue encontrado en muestras litorales obtenidas de la bahía Rodadero, al norte de Colombia. Los especímenes de Colombia comparten las características diagnósticas de N. ferrarii de la descripción original. Sin embargo, los especímenes colombianos muestran cierta variación con respecto al material tipo en: 1) el número de dientes en el labro; 2) la longitud de la espina exopodal externa de la pata 5 de la hembra; 3) la longitud relativa de las setas del palpo mandibular; 4) la relación largo/ancho de la rama caudal; 5) la longitud proporcional de las setas caudales VI / III; 6) la longitud proporcional de las setas caudales VII / VI; 7) la talla del macho; 8) la relación largo/ancho de la rama caudal del macho. Este es el segundo registro de esta especie después de su descripción original en aguas de Belice. En la región Caribe N. ferrarii se asemeja más estrechamente a N. vicinus Herbst, ambos poseen exópodo antenal, anténulas con 12 segmentos en la hembra, la fórmula P3ENP3 de 3, III, pero difieren en la proporción de la rama caudal en la hembra, la longitud de las setas caudales VI / III y VII / VI, el tamaño del macho, el número de segmento de P4ENP, en detalles del armamento del palpo mandibular y en el número de segmentos de la P5 del macho. Esta es la segunda especie de Neocyclops registrada en Colombia y representa una expansión de la distribución conocida de N. ferrarii en la Cuenca del Caribe.

Complementary description of Ergasilus arthrosis Roberts, 1969 (Copepoda: Poecilostomatoida: Ergasilidae), a new parasite of cichlid teleosts in southeast Mexico.

During a parasitological survey of the ichthyofauna of Lake Catemaco, a freshwater system in the Mexican State of Veracruz, the widespread copepod Ergasilus arthrosis Roberts, 1969 was recovered from two cichlid teleosts, Mayaheros urophthalmus (Günther) and Oreochromis sp. This is the first confirmed record of this copepod species outside of the United States and from Mexico; its finding as a parasite of cichlids represents an expansion of the known host range for this copepod. The local prevalence and intensity of infection of E. arthrosis was highest in M. urophthalmus. The infection prevalence of E. arthrosis on M. urophthalmus (60%) was higher than that known for other ergasilids on cichlids. Ergasilus arthrosis can be distinguished from its closest congener E. lizae Krøyer, 1863 by the morphometry of the antennary segments, the ventral ornamentation of the thoracic sclerites and by details of the antennulary setation, but also by its habitat and host preferences. Taxonomic illustrations and morphological details of the specimens examined are also provided together with comments on the variability of this species.