Prevalence of Cymothoidae (Isopoda) Infestation in Bigeye Scad (Selar crumenophtalmus) from Batangas, Philippines

Cymothoid isopod research is relatively scarce in the Philippines, despite the local economic significance of bigeye scad as an inexpensive source of protein and other nutrients. Isopod parasitism has also been shown to have detrimental effects on their fish hosts. The current study aimed to define the host-parasite relationship between cymothoid isopod and bigeye scad by determining cymothoid isopod prevalence, intensity, and host-parasite length correlations in bigeye scad (Selar crumenophthalmus) hosts sourced from Batangas, Philippines. Fish samples were sampled from the Tagaytay City Market in Cavite, which sources fish directly from Batangas. Fish samples were immediately measured and inspected for isopods in the branchial and buccal cavities. Isopods found were extracted, measured, and preserved in ethanol for identification. The isopods were identified as cymothoid isopods and consisted mostly of Norileca indica specimens and one Glossobius impressus. Prevalence and mean intensity of cymothoid isopod infections in bigeye scad were 30% and 1.6, respectively. A possible correlation between isopod size and host size was speculated for non-ovigerous female isopods, but data for male and ovigerous female isopod specimens were inconclusive. The host-parasite size relationships between bigeye scad and isopods are less likely based on body size of either the host or the parasite and are more likely based on other factors such as host cavity size.

A new species of Pseudione sensu lato (Isopoda: Bopyridae) on a squat lobster host from the deep South-West Atlantic

A new bopyrid, Pseudione chiesai n. sp., is herein described based on an ovigerous female and an adult male found in the right branchial chamber on a specimen of Munida spinosa Henderson, 1885. This parasite was collected in the Mar del Plata submarine canyon at 819 m depth during the expedition “Talud Continental I” carried out by the Argentine RV Puerto Deseado in 2012. P. chiesai n. sp. belongs to the Pseudione “crénelés” group sensu Bourdon (1972, 1976), which currently contains seven species, all of which have galatheoid crabs as hosts. P. chiesai n. sp. can be separated from the other species in the Pseudione “crénelés” group by the following combination of characters: (1) both sides of the body convex, (2) frontal lamina with a few, shallow indentations, (3) coxal plates 1–4 and tergal projections 1–4 with distinct irregular margins, mainly on the right side, (4) pereomeres 5–7 with single/branched lateral digitations, (5) maxilliped palp well-developed and setose, and (6) pleon with lateral plates 1–5 distally rounded and directed laterally. The taxonomic position of this new species is briefly discussed.

A new species of the squat lobster genus Uroptychodes Baba, 2004 (Decapoda: Anomura: Chirostylidae) from Japan

A new species of the chirostylid squat lobster genus Uroptychodes Baba, 2004, U. fuscilineatus, is described and illustrated on the basis of a single ovigerous female from the Uraga Channel, central Japan, at depth of 250 m. The new species appears most similar to U. spinimarginatus (Henderson, 1885) and U. yapensis Dong, Gan & Li, 2021 among the 13 known congeners, but is notable in the pereopod 2 not being definitely more slender than the pereopods 3 and 4 and the remarkably spinose pereopods 1–4. A possible association of the new species with crinoid is suggested. An updated identification key to species of Uroptychodes is presented.

Population dynamics of Stenothoe valida Dana, 1852 (Amphipoda, Stenothoidae) at Cheongsapo beach of Busan, Republic of Korea

The population dynamics of Stenothoe valida Dana, 1852 were studied at Cheongsapo beach of Busan, Republic of Korea, from March 2019 to March 2020. Sampling was conducted once a month at low tide during spring tides. Specimens were grouped by the cephalic length at 0.025 mm intervals, and classified into four categories: females, ovigerous females, males and juveniles. The sex ratio, defined as females : total males + females, exceeded 0.5 during most of the study period. Brood size was significantly coupled with ovigerous female size. Two to four cohorts appeared at each study period. New cohorts occurred at almost every sampling except in the samples Jun-2, and Nov-2. Life span was estimated at 1-2 months. The juvenile ratio, the ratio of ovigerous females, and the recruitment rate estimated by FiSAT were commonly high in summer and winter. The life history of S. valida was not coupled with water temperature, but had a strong seasonal pattern.

Two new species of Typton Costa, 1844 from tropical American waters, with taxonomic notes on T. tortugae McClendon, 1911 and a new record of T. granulosus Ayón-Parente, Hendrickx & Galvan-Villa, 2015 (Decapoda: Caridea: Palaemonidae)

Two new species of the palaemonid shrimp genus Typton Costa, 1844 are described based on material from Panama and Mexico. Both species are closely related to T. tortugae McClendon, 1911, a species originally described from the Dry Tortugas, off southern Florida, USA, and later scarcely recorded from other western Atlantic localities, from Bermuda to Mexico and Brazil. Some clarification and additional illustrations are provided for the type material of T. tortugae. Typton jonkayei sp. nov., is described based on material from fouling-encrusting communities dominated by sponges, growing on submerged roots of the red mangrove, Rhizhophora mangle L., in Bocas del Toro, Caribbean coast of Panama. This new species differs from T. tortugae in several morphological details, for instance, on the minor and major chelipeds (second pereiopods), telson, uropod, frontal margin and ambulatory pereiopods. Typton cousteaui sp. nov. is described based on a single ovigerous female dredged in the southern Gulf of California off Baja California Sur, Mexico, previously reported as T. tortugae. This new taxon seems to represent a true cryptic species with no significant morphological divergence from the allopatrically isolated T. tortugae, except for slight morphometric differences. In addition, T. granulosus Ayón-Parente, Hendrickx & Galvan-Villa, 2015 is recorded from the Pacific coast of Panama, based on material collected in the Coiba Archipelago. Some taxonomic, distributional and ecological remarks are provided for T. granulosus and the closely related T. serratus Holthuis, 1951.

Species of Euryplacidae (Brachyura) in western Mexico

Two species of Euryplacidae were collected in western Mexico. Trizocarcinus dentatus (12 localities) and Euryplax polita (4 localities) were both found in the Gulf of California. In the case of E. polita 11 specimens (5 males, 5 females, one ovigerous female) were obtained, while in the case of T. dentatus 42 specimens (25 males, 10 females, 7 ovigerous females) were collected. The northern distribution limit of E. polita is extended to the northern Gulf of California (28°16′N 111°36′W). Environmental data for both species are provided, including depth range, temperature, dissolved oxygen, and sediment composition.

A new deep-sea species of Epimeria Costa in Hope, 1851 (Amphipoda, Amphilochidea, Epimeriidae) from off southwestern Mexico

A single ovigerous female specimen of a new species of Epimeria Costa in Hope, 1851 was collected from deep sea, off southwestern Mexico, in the eastern Pacific. Epimeria karamani sp. nov., is most similar to females of E. cora J.L. Barnard, 1971, E. pacifica Gurjanova, 1995 and Epimeria morronei Winfield, Ortiz & Hendrickx, 2013. However, it differs from these species by: eyes long and slightly kidney-shaped; pleonite 3 strongly carinate, with dorsal tooth produced and acute; urosomite 1 with a wide mid-dorsal notch and a strong, upright blunt tooth; coxa 3 anterior margin slightly truncate and with two processes marginally; coxa 4 ventral margin linear, with facial granules and simple setae; gnathopods palm with distal bifid setae; telson straight medially, distal margin crenulate and with minute setae. The new species described herein increases the number of Epimeria species from the Pacific Ocean to 14, and from the eastern Pacific to three.

Preliminary investigation of the critically imperiled Caney Mountain cave crayfish Orconectes stygocaneyi (Hobbs III, 2001) (Decapoda: Cambaridae) in Missouri, USA

The Caney Mountain cave crayfish (Orconectes stygocaneyi) is one of North America’s rarest crayfish, endemic to one cave in southern Missouri, USA. The species is listed as “critically imperiled” by Missouri, and “threatened” by the American Fisheries Society. Previously, only 15 crayfish have been observed in Mud Cave, and only two have been collected (for original species description). We aimed to collect the first natural history data on the species and search adjacent caves and springs for additional populations. Twelve visual searches and supplemental trapping over four years, in all seasons, yielded 69 O. stygocaneyi (including 11 young-of-year) observations and capture of 22 crayfish, including one ovigerous female. Visual searches of nearby caves and springs yielded no O. stygocaneyi records. However, multiple surveys of those caves and springs, using environmental DNA detected the species in one additional cave adjacent to Mud Cave, but only during spring high flow events when the caves may be ephemerally connected. Orconectes stygocaneyi’s distribution is among the most restricted of any North American crayfish, and further evaluation of its conservation status designations might be warranted. Long term conservation of O. stygocaeyi would benefit from management practices promoting sustained, unimpacted surface runoff within Mud Cave’s recharge area.

A new species of the hairy crab genus Pilumnus (Decapoda: Brachyura: Pilumnidae) from Belize

A new species of the pilumnid crab genus Pilumnus Leach, 1815, P. mantelattoi n. sp., is described and illustrated on the basis of a single ovigerous female specimen from Belize, bordering the northwestern Caribbean Sea. The holotype, an ovigerous female, was taken from an epifaunal accumulation of sponges, ascidians, and hydroids on red mangrove roots suspended in the water column. Superficially resembling Pilumnus floridanus Stimpson, 1871, with which it occurs sympatrically, it is distinguished from this and all other known western Atlantic species on the basis of both morphology and molecular markers.

Morphology of the complete larval stages of Portunus segnis (Forskål, 1775) (Crustacea: Brachyura: Portunidae) from the Gulf of Aqaba, Saudi Arabia

Portunus pelagicus (Linnaeus, 1758) sensu lato has been recognized as a species complex comprising four species. Of these four species, the larval stages of all except Portunus segnis (Forskål, 1775), have been described. The larvae of P. segnis, hatched from an ovigerous female, caught in the Gulf of Aqaba, were cultured in the laboratory up to the megalopa stage. All the larval stages are described herein for the first time. The number of aesthetascs of the antennules of all the zoeal stages of P. segnis differs from those of the larvae of the other species of the P. pelagicus species complex. In the telson forks of zoea I–IV of P. segnis, there is a pair of ventral spines and two pairs of dorsal spines, whereas in the other P. pelagicus species complex larvae, there is a pair each of ventral and dorsal spines. Another unique feature, in the megalopa of P. segnis, are two endopod hooks in pleonites I–V. Different zoeal and megalopal stages of P. segnis can be distinguished clearly from the other P. pelagicus species complex larvae based on the number of setae and patterns of different appendages.