Exopodal Setae Research Articles

First record of the freshwater copepod Mesocyclops paranaensis Dussart & Frutos, 1986 (Copepoda: Cyclopoida: Cyclopidae) from Colombia

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.

Two new species of the similis-subgroup of Triconia Böttger-Schnack, 1999 (Copepoda, Oncaeidae) and a redescription of T. denticula Wi, Shin & Soh, 2011 from the northeastern equatorial Pacific

Three species of the similis-subgroup of the genus TriconiaBottger-Schnack, 1999 in the family Oncaeidae Giesbrecht, 1893 [“1892”] are described based on specimens collected by using a fine mesh net in the northeastern equatorial Pacific Ocean. One species is newly recorded in the equatorial Pacific, and the other two species are new to science. Triconia komo n. sp. is closely related to T. hawii (Bottger-Schnack & Boxshall, 1990), but differs distinctly in the relative length of the outer basal seta on P5 in the female as well as slightly in the relative length of the seta VI on caudal ramus in both sexes. Triconia onnuri n. sp. closely resembles T. similis (Sars, 1918), but females can be distinguished by the relative length of the outer exopodal seta and the outer basal seta on P5. Both sexes differ from T. similis in the relative lengths of endopodal spines on swimming legs 3 and 4 as well as in the form of caudal seta VI. The female of Triconia denticulaWi, Shin & Soh, 2011, which is newly recorded in the equatorial Pacific, is redescribed including morphological details and differences compared to the original description from Korean waters. The type material of T. denticula deposited in the National Institute of Biological Resources, Incheon (NIBR) was re-examined and found to be inconclusive for taxonomic purposes because the deposited copepod material and its labelling does not correspond to the description of the species. A fundamental revision of the type material of T. denticula is required. The present account includes an indication of the intraspecific variation in the endopodal spine lengths on swimming legs 2 to 4 for all three species, which is essential for assessing the usefulness of these characters for unequivocal identification of Triconia species. The spine lengths on exopodal segments 1 and 2 on swimming legs 3 and 4 are proposed as new morphometric characters for the identification of males of Triconia species, which are otherwise very similar in morphology.

New records of benthic harpacticoids from Korea: I. Three new species of the genus Zosime Boeck (Copepoda: Harpacticoida: Zosimeidae)

ABSTRACTTaxonomic studies of benthic harpacticoids from sublittoral habitats in the Southern Sea of Korea were performed. Three new species belonging to the genus Zosime Boeck, 1873 were discovered: Zosime comata sp. nov., Z. changi sp. nov., and Z. gymnokosmosa sp. nov. They all belong to the typica group, which is characterized by diagnostic female features of a mandibular exopod with three setae, leg 5 fused with baseoendopod bearing an exopodal seta arising from the anterior surface, and elongate caudal rami with a length more than 1.6 times its width. These three new species unusually have only two outer spines on the distal exopodal segments of legs 1–4, a character is unique in the genus except for Z. bathyalis Por, 1967, in contrast to the three outer spines on the corresponding segments in other congeners. However, the three new species can be distinguished from Z. bathyalis and each other by body ornamentation, segmentation of the female antennule, setation of the distal endopodal segment on legs 2–4, and an endopodal lobe on leg 5 in both sexes. Detailed descriptions and illustrations of these three new Zosime species are provided.

First zoeal stage of Plesionika crosnieri Chan Yu, 1991, P. ortmanni Doflein, 1902, and P. semilaevis Bate, 1888, with remarks on the early larvae of Plesionika Bate, 1888 (Crustacea, Decapoda).

The morphology of first stage zoea larvae of three pandalid shrimps Plesionika crosnieri Chan Yu, 1991, P. ortmanni Doflein, 1902, and P. semilaevis Bate, 1888 are described for the first time from larvae obtained in laboratory culture. The zoea I is compared amongst those species of the genus Plesionika with larval morphology known. It is found that the length of the rostrum, the number of anteroventral denticles on the carapace, presence of exopodal setae in the maxillule, and setation pattern of the peduncle of antennule, endopod of antenna, and coxa/basis of maxillipeds are useful characters in distinguishing these larvae.

Digestive and appendicular soft-parts, with behavioural implications, in a large Ordovician trilobite from the Fezouata Lagerst\xe4tte, Morocco

Trilobites were one of the most successful groups of marine arthropods during the Palaeozoic era, yet their soft-part anatomy is only known from a few exceptionally-preserved specimens found in a handful of localities from the Cambrian to the Devonian. This is because, even if the sclerotized appendages were not destroyed during early taphonomic stages, they are often overprinted by the three-dimensional, mineralised exoskeleton. Inferences about the ventral anatomy and behavioural activities of trilobites can also be derived from the ichnological record, which suggests that most Cruziana and Rusophycus trace fossils were possibly produced by the actions of trilobites. Three specimens of the asaphid trilobite Megistaspis (Ekeraspis) hammondi, have been discovered in the Lower Ordovician Fezouata Konservat-Lagerstätte of southern Morocco, preserving appendages and digestive tract. The digestive structures include a crop with digestive caeca, while the appendages display exopodal setae and slight heteropody (cephalic endopods larger and more spinose than thoracic and pygidial ones). The combination of these digestive structures and the heteropody has never been described together among trilobites, and the latter could assist in the understanding of the production of certain comb-like traces of the Cruziana rugosa group, which are extraordinarily abundant on the shallow marine shelves around Gondwana.

A new marine cyclopoid copepod of the genus Neocyclops (Cyclopidae, Halicyclopinae) from Korea.

A new cyclopoid species of the genus Neocyclops Gurney, 1927 is described. Type specimens were collected from a beach on south-western coast of the Korean Peninsula by rinsing intertidal coarse sandy sediments. Neocyclops hoonsooi sp. n. is most characteristic in showing the conspicuous chitinized transverse ridges originating from the medial margins of the coxae of all swimming legs. The new species is most similar to Neocyclops vicinus, described from the Brazilian coast, and Neocyclops petkovskii, from Australia. All three species share a large body size (more than 750 µm long), the presence of an exopodal seta on the antenna, two setae on the mandibular palp, the same seta/spine armature on the third endopodal segment of leg 3 (3 setae + 3 spines), and the fairly long inner distal spine on the third endopodal segment of the female leg 4. However, Neocyclops hoonsooi sp. n. differs from both species by the much shorter caudal rami (less than 1.7 times as long as wide) and the shorter dorsal caudal seta VII. Furthermore, Neocyclops hoonsooi is clearly distinguished from Neocyclops vicinus by the 10-segmented antennule (vs 12 segments in Neocyclops vicinus), and from Neocyclops petkovskii by the elongate inner distal spine on leg 5 exopod and the 3-segmented leg 5 in male (vs 4-segmented in Neocyclops petkovskii). A tabular comparison of characters separating Neocyclops hoonsooi from its closest allies and a key to Neocyclops species from the Indo-Pacific Ocean are provided. This is the first record of the genus Neocyclops from the northern Pacific.

Two new species of ectinosomatid copepods (Harpacticoida: Ectinosomatidae) from the Caribbean coast of Colombia

Biological samples from the lagoonal system Laguna Navío Quebrado, Caribbean Colombian coast, yielded 2 undescribed species of harpacticoid copepods of the family Ectinosomatidae. The first species, Halectinosoma arangureni sp. nov., is most closely related to H. langi Wells, 1967, H. curticorne (Boeck, 1873) and H. abyssicola (Bodin, 1968), but diverges from these congeners in: 1) the length-width ratio of the maxillipedal basis; 2) the outer caudal seta(II)/caudal ramus length ratio; 3) details of the mandible palp and blade; 4) the length of the inner exopodal seta of P5; 5) the accessory seta on the male P5 exopod, and 6) a T-shaped incision on the male third urosomite. The second species, Pseudobradya gascae sp. nov. closely resembles P. robusta Sars, 1910 and P. barroisi (Richard, 1893), but diverges from these species by: 1) the number of antennular segments in the female; 2) the absence of a seta on the antennary EXP2; 3) proportions of the maxilliped; 4) the relative length of P1EXP; 5) caudal seta III/caudal ramus length ratio, and 6) the unusually long middle seta of P5EXP. Both genera are recorded for the first time in Colombia.

A new species of Schizopera (Copepoda: Harpacticoida: Miraciidae) from Colombia

ABSTRACTObjective. The present contribution aims at the description of a new species of the genus Schizopera. Materials and methods. Water samples were collected in littoral areas with mangrove and macrophytes, and in the limnetic zone. Twenty five liters of water were taken. Water samples were filtered with a zooplankton net (45μm) and preserved in 70% ethanol. The filtered samples were concentrated to 100 ml and examined in a Bogorov camera. Copepods were separated. Observations and drawings of S. evelynae sp. nov. were made at a magnification of 1000X. Results. Schizopera evelynae sp. nov. seems to be closely related to S. giselae Jiménez -Álvarez 1988 and to S. pratensis Noodt 1958 based on the armature formula of P1-P4, but can be separated from these two species based on the relative length of P1ENP, length/width ratio of P1ENP2, relative length of the outer proximal and distal spines on P4EXP3, shape of the exopod and relative length of the exopodal setae of the female P5, shape and length/width ratio of the male P2ENP2, and male P5 baseoendopodal lobe:exopod length ratio. A key to the species of Schizopera from America is given. Conclusion. A new species of the genus Schizopera is described. The Colombian material shares most characters with S. giselae and S. pratensis.

A new species of Peltidium Philippi, 1839 (Crustacea, Copepoda, Harpacticoida) from the Pacific coast of Mexico

During the analysis of phytal meiobenthic samples collected from a rocky-sandy beach in the state of Nayarit, in the Mexican Pacific, several specimens of harpacticoid copepods were obtained and taxonomically examined. These specimens were found to represent an undescribed species of the peltidiid genus Peltidium Philippi, 1839. The new species, Peltidium nayarit sp. n. is described herein. It resembles Peltidium nichollsi Geddes and Peltidium lerneri Geddes from Bahamas but also the widespread Peltidium speciosum Thompson & Scott and Peltidium purpureum Philippi. The new species from the Mexican Pacific differs from its known congeners by its possession of a unique combination of characters, including a modified pectinate seta on the antennary exopod, three terminal setae on the second endopodal segment of leg 1, third exopodal segment of leg 1 with three elements, inner terminal claw twice as long as outer claw, female fifth leg with 5 exopodal setae, exopodal setae I-III stout, spinulose and seta IV being as long as seta V. This is the second species of the family known to be distributed in the Eastern Tropical Pacific and in Mexico. Pending additional data, the distribution of this species appears to be restricted to this area of the Mexican Pacific.

Two new species belonging to the dentipes- and conifera-subgroups of Triconia (Copepoda: Cyclopoida: Oncaeidae) from the East China Sea

Two new species of Triconia in Oncaeidae, including both sexes of Triconia constricta n. sp. and females of Triconia pararedacta n. sp., are described from south of Jeju Island in the East China Sea. Triconia constricta belongs to the dentipes-subgroup of Triconia characterized by the absence of integumental pockets on the anterior surface of the labrum. It is distinguished from the closely related species of this subgroup, T dentipes (Giesbrecht, 1891), T elongata Bottger-Schnack, 1999, and T giesbrechti Bottger-Schnack, 1999, by the following combination of morphological features in females: 1) lateral margins of genital double-somite in dorsal view slightly constricted at midlength; 2) P5 with very long outer basal seta, reaching beyond paired secretory pores on posterior part of genital doublesomite, as well as distinctive length ratios of exopodal setae; in both sexes; 3) length ratios of caudal setae, and 4) relative spine lengths on distal endopodal segments of swimming legs 2 to 4. Triconia pararedacta is a member of the conifera-subgroup characterized by a dorsal projection on the second pedigerous somite in the female. It differs from females of other species of this subgroup in the following: 1) very small-sized dorsal projection on second pedigerous somite, 2) different length to width ratio of P5 exopod, 3) relative lengths of outer basal seta and exopodal setae of P5, and 4) different length ratio of outer distal spine to distal spine on endopods of P2-P4. Additional character states are proposed for defining the dentipes-subgroup within Triconia and for recognizing three sets of species within the conifera-subgroup.

A review ofLeptocarisincluding a description ofL. ryukyuensissp. nov. (Copepoda: Harpacticoida: Darcythompsoniidae)

We provide a review on scientific contributions concerned withLeptocaris(Harpacticoida: Copepoda) that includes the zoogeography, ecology, biology, and morphology of this genus. A tabular key is given to aid in the identification of theignavus-group.Leptocaris ryukyuensissp. nov. is included on the basis of specimens collected from Akeijima sandy beach of the Ryukyu Islands in Japan. The new species can be distinguished from its congeners by an abexopodal seta and 3 exopodal setae on A2, a barbed inner seta on the proximal, endopodal segment of female P1 to P3, setae of the caudal ramus (setae I and II are very small, and the basal seta is transformed to a big spine), and modified inner setules of P2 enp-2 and P3 enp-2 in the males. The new species belongs to theignavus-group established by Kunz (1994) and is the third species of the genusLeptocarisin East Asia.

Early zoeal development of the shrimp Hippolyte leptocerus (Decapoda, Caridea, Hippolytidae) GUILLERMO GUERAO (Spain), ESTEBAN HERNÁNDEZ (Spain) & ÁNGEL URZÚA (Germany)

The morphology of the first three zoeal stages of Hippolyte leptocerus (Heller, 1863) are described and illustrated in detail from laboratory-hatched material. The ovigerous females were collected on the Alfacs Bay, Ebro Delta, Spain (Western Mediterranean). The early larval stages (ZI, ZII, ZIII) showed the anterolateral margin of carapace with denticulations, a median tubercle behind rostrum, scaphocerite segmented distally (only ZI and ZII), exopodal seta at the maxillule and pleonite 5 with a pair of dorsolateral spines. The morphology of the first three zoeal stages of H. leptocerus is typical of species with an extended larval development. Morphological characteristics of the genus Hippolyte are discussed.

Taxonomic re-examination and distribution of copepods reported as Oncaea notopus Giesbrecht, 1891 (Copepoda, Oncaeidae) in the Mediterranean Sea

A new species of the pelagic marine copepod family Oncaeidae, Oncaea serrulata, is described from the Mediterranean Sea. The species belongs to the notopus-group of Oncaeidae, which are characterized by a long, free exopod on leg 5. It differs from Oncaea notopus Giesbrecht 1891 and any other described species of this group by a combination of morphological characters, including: (1) the relative lengths of distal endopod spines on swimming legs 2 and 3, (2) the denticulate ornamentation of the exopod segment and the two exopodal setae on leg 5, (3) the proportional lengths of the caudal setae, and (4) the comparatively small body length. The species occurs widespread in the Mediterranean Sea in mesopelagic and deep-sea layers down to 3,000 m depth and was also found in near-bottom sediment traps moored at a bottom depth of 2,347 m in the Ligurian Sea. O. serrulata appears to be the only representative of the notopus-group in the Mediterranean Sea and seems to have consistently been confounded with the allegedly cosmopolitan O. notopus Giesbrecht in most earlier studies in this area. The taxonomic history of Giesbrecht’s O. notopus, which was originally described from the Pacific, is summarized and morphological identification parameters applicable for the species identification of notopus-type oncaeids are discussed. In the future, identification may be facilitated by using genetic barcodes in comparison with those recently analysed for the Mediterranean O. serrulata (as Oncaea sp. 7 sensu Bottger-Schnack 1997). Published data on the zoogeographical and vertical distribution as well as the abundance of notopus-type oncaeids in the Mediterranean Sea are reviewed. Possible causes for the lack of positive records of this taxon in Mediterranean studies earlier than 1980 are discussed.

Revision of the larval morphology (Zoea I) of the family Hippolytidae (Decapoda, Caridea), with a description of the first stage of the shrimp Hippolyte obliquimanus Dana, 1852

The aim of this study was to summarize the available data on larval morphology of the first zoea of the family Hippolytidae and describe the first zoeal stage of H. obliquimanus from two geographically distinct populations, Brazilian and Caribbean in order to discuss interand intraspecific variability. Ovigerous females of Hippolyte obliquimanus were collected at Cahuita (Limón, Costa Rica) and at Ubatuba (São Paulo, Brazil). We compiled the published descriptions of all available hippolytid Zoea I (66 spp., 21%), and all zoeae share several characteristics. However, such morphological features cannot be used to distinguish the first zoeae of Hippolytidae from other caridean larvae. Historically, the presence of an exopodal seta at the maxillule and the absence of the anal spine/papilla have been considered as characteristic for the Zoea I of the genus Hippolyte. The results of our revision, however, did not support these conclusions: although H. obliquimanus showed an exopodal seta at the maxillule, four congeners did not bear such structure; moreover, H. obliquimanus as well as one other congener have an anal spine/papilla. All morphological characters observed in the first zoeal stage of H. obliquimanus are shared with others species of the family Hippolytidae. Intraspecific variability in Hippolyte obliquimanus was detected in one morphological aspect: the first zoea had four denticles on the ventral margin of the carapace in the Brazilian population, while specimens from the Costa Rican population had three.

Revision of the larval morphology (Zoea I) of the family Hippolytidae (Decapoda, Caridea), with a description of the first stage of the shrimp Hippolyte obliquimanus Dana, 1852

The aim of this study was to summarize the available data on larval morphology of the first zoea of the family Hippolytidae and describe the first zoeal stage of H. obliquimanus from two geographically distinct populations, Brazilian and Caribbean in order to discuss interand intraspecific variability. Ovigerous females of Hippolyte obliquimanus were collected at Cahuita (Limon, Costa Rica) and at Ubatuba (Sao Paulo, Brazil). We compiled the published descriptions of all available hippolytid Zoea I (66 spp., 21%), and all zoeae share several characteristics. However, such morphological features cannot be used to distinguish the first zoeae of Hippolytidae from other caridean larvae. Historically, the presence of an exopodal seta at the maxillule and the absence of the anal spine/papilla have been considered as characteristic for the Zoea I of the genus Hippolyte. The results of our revision, however, did not support these conclusions: although H. obliquimanus showed an exopodal seta at the maxillule, four congeners did not bear such structure; moreover, H. obliquimanus as well as one other congener have an anal spine/papilla. All morphological characters observed in the first zoeal stage of H. obliquimanus are shared with others species of the family Hippolytidae. Intraspecific variability in Hippolyte obliquimanus was detected in one morphological aspect: the first zoea had four denticles on the ventral margin of the carapace in the Brazilian population, while specimens from the Costa Rican population had three.

A newAllocyclops(Crustacea, Copepoda, Cyclopoida) from bromeliads and records of freshwater copepods from Mexico

Suárez-Morales E., Mendoza F. & Mercado-Salas N. 2010. — A new Allocyclops (Crustacea, Copepoda, Cyclopoida) from bromeliads and records of freshwater copepods from Mexico. Zoosystema 32 (3): 393-407.The cyclopoid copepod fauna of freshwater systems of the Mexican state of Veracruz, on the Gulf coast of Mexico, was completely unknown. During routine surveillance for larval mosquitoes, several types of aquatic habitats, including ephemeral ponds, springs, and bromeliads, were sampled and cyclopoid copepods were taxonomically studied. Five species were identified, among them a new species of the cyclopine genus Allocyclops Kiefer, 1932. This species, collected from the bromeliad Tillandsia heterophylla Morren, 1873, resembles A. excellens Kiefer, 1956, A. consensus Karanovic, 2003, and A. silvaticus Rocha & Björnberg, 1988, but it can be easily distinguished by its strong, ornamented anal operculum and the shape of the genital double somite, among other characters. The new species is tentatively assigned to the subgenus Psammocyclops sensu Karanovic by having an exopodal seta on the antenna, but it is clear that the subgeneric limits should be revised with a complete set of characters. The genus has not been hitherto found from bromeliads. This is also the first record of Allocyclops in continental North America and the first records of freshwater cyclopoid copepods from this part of Mexico.

Taxonomy of Oncaeidae (Copepoda, Cyclopoida s.l.) from the Red Sea. IX. Epicalymma bulbosa sp. nov., first record of the genus in the Red Sea

The oncaeid genus Epicalymma comprises small copepod species usually living at meso- and bathypelagic depth layers in oceanic areas. The genus had previously been assumed to be absent from the Red Sea, due to the unusually high deep-sea temperatures and salinities in this area. In the present account a new species, Epicalymma bulbosa, is described from the Red Sea, which appears to be the only representative of the genus in the region. The new species is the smallest Epicalymma species so far recorded, with a total body length of ∼0.32 and ∼0.29 mm in the female and male, respectively. Apart from its small size, it differs from all known Epicalymma species by an extremely long exopodal seta on P5 in both sexes, and by a free exopod segment of P5 and a very long and basally swollen spinule on the syncoxa of the maxilliped in the female. In contrast to other Epicalymma species, which are distributed between 500 and >2500 m depth, the new species occurred much shallower (100–750 m) in the Red Sea, which may be interpretated as an avoidance mechanism of the unfavourable environmental conditions in the deep Red Sea. The taxonomic status of the new species within the genus Epicalymma is discussed and the few available ecological data on Epicalymma species in the world ocean are summarized.

Two New Species of <i>Monstrillopsis</i> Sars (Crustacea: Copepoda: Monstrilloida) from the White Sea and Norway, with Comments on <i>M. dubia</i> Scott

A new species of monstrilloid copepod, Monstrillopsis ferrarii n. sp., based on four adult female specimens collected in the White Sea, northern Russia, is described and illustrated. The new species is most closely related to M. dubia Scott from Scotland and the Mediterranean and M. dubia (sensu Sars, 1921) from Norwegian fjords. The latter is considered to represent a distinct species, described herein as M. dubioides n. sp. It differs from M. dubia in characters related to antennule length compared to body length, but mainly to the shape and relative size of the genital double somite and other urosomal somites. Records of M. dubia in Norway and off Lisbon are referable to M. dubioides n. sp. On the other hand, M. ferrarii n. sp. differs from M. dubia, M. dubioides, and the other species of the genus by a combination of characters, including 1) two rounded protuberances in the cephalic area, flanking the ocelli; 2) a wide zone of transverse cuticular striations encircling the cephalic area; 3) very long exopodal setae on the fifth legs, with no distal elongation of the exopodal lobe beyond the setal bases; 4) a relatively long genital double somite with the margins of the anterior half produced laterally; and 5) the nearly equal sizes of the anal somite and the preceding somite. It is considered that M. dubia and related forms represent a species complex with subtle morphological differences and a wide distribution. This is the first record of a species of Monstrillopsis in Russia and the sixth species of this order to be recorded in polar environments.

The complete larval development of the spider crab, Macropodia parva (Crustacea, Decapoda, Majidae) from laboratory culture

Summary Two zoeae and the megalopa of the majid crab Macropodia parva were obtained from laboratory material. At 25±1°C and 35% salinity, the first crab appeared 12 days after hatching; survival to the first crab instar was 27%. The larval stages are described in detail and compared with those of the previously described species of the genus Macropodia. Zoeal characteristics of M. parva that differentiate it from other known Macropodia larvae are the naked telson furcae and the absence, in zoea II, of the exopodal setae on the basis of the maxillule.

Two new species of the Diacyclops languidoides-group (Copepoda, Cyclopoida) from groundwaters of Austria

Two new syntopic species of the Diacyclops languidoides-group (D. danielopoli n. sp. and D. felixn. sp.) are described from interstitial groundwaters of Lobau wetlands, Austria. Both species lack the exopodal seta on antenna basipod, but differ in several minute morphological details of antennules, antennae, maxillulary palp, coxal plates, P4 basipod and caudal rami. Some of these characters are present in D. danielopoli n. sp. in an apomorphic state (reduction of setation patterns, longer aesthetascs on male and female antennules, absence of exopodal seta on maxillulary palp, longer dorsal caudal seta) suggesting a higher degree of specialization to the subterranean environment than in D. felix n. sp. The relationship between the reduction of setation patterns on mouthparts and the degree of stygobitization in the Diacyclops languidoides-species group is critically discussed.