Abstract The present paper describes a new species of freshwater crayfish of the genus Parastacus Huxley, 1879 from the municipality of Amaral Ferrador in the state of Rio Grande do Sul, southern Brazil, evaluates its conservation status according to the IUCN Red List Criteria (sub-criterion B1), and updates the identification key for the genus. Parastacus longidactylus sp. n. differs from all analyzed species by the large eyes, the prominent and wide rostral carinae, surpassing the rostral basis and extending to the proximal third of the postorbital carinae, postorbital carinae and rostral carinae prominent and with similar lengths, chelipeds carpus dorsomedial surface not divided longitudinally by groove and long dactylus, surpassing the fixed finger. The possible extent of occurrence was estimated to be 6,968 km² and the species was recorded in only one location in the Camaquã River basin. The main threats to the region are the replacement of native vegetation by crops and livestock, water pollution and soil erosion. However, because there is only one known location where Parastacus longidactylus sp. n. occurs we suggest classifying the species as Data Deficient. Huxley 187 Sul Brazil subcriterion sub criterion B1, B1 B , B1) sp n eyes lengths dactylus finger 6968 6 968 6,96 km basin livestock erosion However Deficient 18 696 96 6,9 1 69 9 6,

Abstract Herpyllobiid copepods are highly transformed mesoparasites that infect marine benthic polychaete annelids. The genus Herpyllobius Steenstrup and Lütken, 1861, the most diverse in the family, was known to infect exclusively polychaetes of the family Polynoidae, but it was recently reported also on another family. Species of Herpyllobius have been reported mainly from cold latitudes including Arctic and Antarctic areas, except for two subtropical species. During the taxonomic examination of flabelligerid polychaetes collected from a Western Australian coral reef system, a mesoparasitic copepod was found infecting a specimen of Lamispina horsti (Haswell, 1892). The copepod represents an undescribed species of Herpyllobius. The new species, Herpyllobius paulayi n. sp. belongs to a group of congeneric species (Group III) lacking intergenital processes or sclerotized dots. It diverges from the other species in this group by its possession of a unique combination of characters: 1) a globose ectosoma with pilose surface; 2) elongate, thick cylindrical egg sacs with +10 egg rows; 3) endosoma discoid, short, with two lateral, asymmetrical flattened processes and a medial lobe; 4) it attaches to the host prostomium; and 5) it infects a non-polynoid subtropical polychaete species. annelids Lütken 1861 Polynoidae areas system Haswell, Haswell (Haswell 1892. 1892 . 1892) n sp Group III dots characters 1 surface 2 elongate 10 +1 rows 3 discoid short lateral lobe 4 prostomium 5 nonpolynoid non polynoid 186 189 + 18

Abstract Heterochely is an important phenomenon in decapod crustaceans. Nevertheless, it was rarely examined in freshwater crayfish. Therefore, the aim of this study was to investigate cheliped loss and abnormalities of the narrow-clawed crayfish, Pontastacus leptodactylus. The crayfish samples were captured using 17 mm mesh-sized fyke-nets from Atikhisar Reservoir in Çanakkale, Turkey between July 2020 and June 2021. The cheliped loss was classified and compared between sexes and length groups. The cheliped surface was calculated for each specimen for both the right and left cheliped. Results of the study indicate that the percentages of the sampled individuals were 5.46% for the right cheliped missing group, 5.23% for the left cheliped missing group, 10.37% for both chelipeds missing group, and 78.94% for both chelipeds present group. There was a statistical difference between cheliped loss and size groups (p < 0.05). Although cheliped loss is almost non-existent in low-size groups (10.0-29.9 mm), it reaches high values in the 40.0-69.9 mm size groups. The most intense loss occurs in the 40.0-49.9 and 50.0-59.9 mm size groups. It was determined that 10.69% of the sampled individuals examined had a single cheliped (10.03% female, 11.14% male). A statistically significant difference was found between cheliped loss and sex (p < 0.05). The percentage of female and male individuals with no chelipeds is 9.83% for females and 10.73% for males, and with both chelipeds it is 80.14% for females and 78.14% for males. While the number of abnormalities observed in chelipeds was higher in males, abnormalities in both chelipeds were higher in females. Moreover, it was found that cheliped loss significantly differed according to the months of collection (p < 0.05). Cheliped losses increased in July, August, and September when feeding was comparatively intense. In conclusion, the fact that the individuals were obtained alive, was an indication that the abnormalities detected did not significantly affect their vital activities directly. However, morphological abnormalities in the appendages, especially in the chelipeds, may impair their functional use compared to a healthy cheliped. This abnormal condition is assumed to share the disadvantageous limitations experienced by the absence of a cheliped. crustaceans Nevertheless Therefore narrowclawed narrow clawed leptodactylus 1 meshsized mesh sized fykenets fyke nets Çanakkale 202 2021 546 5 46 5.46 group 523 23 5.23 1037 10 37 10.37 7894 78 94 78.94 p 0.05. 005 0.05 . 0 05 0.05) nonexistent non existent lowsize low 10.029.9 100299 10.0 29.9 29 9 (10.0-29. mm, , mm) 40.069.9 400699 40.0 69.9 40 69 40.0-69. 40.049.9 400499 49.9 49 40.0-49. 50.059.9 500599 50.0 59.9 50 59 50.0-59. 1069 10.69 10.03% 1003 03 (10.03 1114 11 14 11.14 male. male) 983 83 9.83 1073 73 10.73 males 8014 80 80.14 7814 78.14 Moreover August conclusion alive directly However appendages 20 54 4 5.4 52 2 5.2 103 3 10.3 789 7 78.9 00 0.0 029 10.029. 10029 100 10. 299 29. (10.0-29 069 40.069. 40069 400 40. 699 69. 6 40.0-69 049 40.049. 40049 499 49. 40.0-49 059 50.059. 50059 500 50. 599 59. 50.0-59 106 10.6 10.03 (10.0 111 11.1 98 8 9.8 107 10.7 801 80.1 781 78.1 5. 78. 0. 02 10.029 1002 (10.0-2 06 40.069 4006 40.0-6 04 40.049 4004 40.0-4 50.059 5005 50.0-5 (10. 11. 9. 80. 10.02 (10.0- 40.06 40.0- 40.04 50.05 50.0- (10 (1 (

Abstract Intermediate metabolism and oxidative balance markers help to better understand environmental dynamics and how they influence the physiological patterns of organisms. Procambarus clarkii (Girard, 1852), a crayfish native to the United States of America and Mexico, represents an appealing case study for understanding invasive species’ metabolic dynamics. This species has sexual dimorphism and two male morphotypes: reproductive (M1) and non-reproductive (M2). We evaluated the seasonal variations of biomarkers in M1 and M2 males, collected in each season of 2016 at Parque Alfredo Volpi (São Paulo, Brazil). Hemolymph, hepatopancreas and abdominal muscle samples were extracted to determine markers of intermediate metabolism, oxidative balance, the hepatosomatic index and the stomach repletion degree. The results showed differences between the two male morphotypes. M1 showed a predominance of medium to full stomachs throughout the year, with an allocation of energetic substrates mainly used in reproduction (gametogenesis and reproductive behaviors). They also presented increased lipoperoxidation, SOD and GST activities. M2, on the other hand, had a lower capacity to allocate energy reserves in the period leading up to and during reproduction, which may be associated with a lower degree of gastric repletion. However, M2 maintained alternating antioxidant strategies that helped preserve low levels of lipoperoxidation in the hepatopancreas throughout the year. This pattern observed for the degree of gastric repletion indicates an intraspecific competition between the categories of males, which, together with the profile of energy reserve usage, seems decisive for M2 to reproduce. organisms Girard, Girard (Girard 1852, 1852 , 1852) Mexico morphotypes M (M1 nonreproductive non M2. . (M2) males 201 São Paulo Brazil. Brazil Brazil) Hemolymph year gametogenesis behaviors. behaviors behaviors) activities hand However usage reproduce 185 (M (M2 20 18 2 1

Abstract Isopods of the suborder Cymothoida include ectoparasite species that cause physical damage and affect the development of the host by feeding on blood and tissues. On fishes, these parasites attach themselves to the skin, fins, gills, and oral cavity using claws on articulated legs. The ability to remain hidden in cavities even after the fish is caught enables isopods to be transported to new areas along with the host, making these parasites potential co-invaders. Understanding the role and environmental impact of parasites is essential, although research on parasitism in the context of biological invasions lags in comparison to general research on such invasions. Previous records indicate only two species of parasitic isopods in the São Francisco River basin. However, the present study reports the first record of two other species (Braga patagonica and Braga nasuta) on Pygocentrus piraya and in the basin itself. This demonstrates a lack of knowledge regarding fish parasites in the region, despite the presence of other parasites. Collaborations with research groups conducting fish sampling in the basin can contribute to expanding knowledge on these parasites and the training of human resources in fish parasitology. The present study provides important information on the presence of unidentified parasitic isopods on fishes in the São Francisco River basin, underscoring the need for further studies and expanding the geographic distribution of these parasites, as well as the host list for these isopods. tissues skin fins gills legs coinvaders. coinvaders co invaders. invaders co-invaders essential However nasuta itself region parasitology

ABSTRACT The calanoid copepod family Epacteriscidae is one of the most representative cave-dwelling copepods worldwide, especially in the Caribbean region. We provide new records of two epacteriscid copepods from anchialine habitats of the Yucatan Peninsula (YP); both were previously known only from their type locality in Jamaica and Caicos Islands. We document the occurrence of Edaxiella rubra Fosshagen, Boxshall and Iliffe, 2001 in Cozumel Island and Bofuriella spinosa Fosshagen and Iliffe, 2007 in Playa del Carmen, the adjacent continental region of the YP. We found slight morphological differences compared to the original descriptions of both species, including some characters not previously described; also, the male of B. spinosa remained unknown and is herein described. These records show the growth of the epacteriscid copepod listings and expand the morphological knowledge of these species in the Yucatan Peninsula into the Western Caribbean, likely harboring one of the most diverse anchialine copepod fauna worldwide and currently going through intense anthropogenic pressure, thus enhancing the intrinsic value of these new findings. It is expected that new samplings will reveal the true diversity and distribution of the Mexican Caribbean anchialine copepod fauna, where knowledge of its biological diversity is still incipient. cavedwelling cave dwelling YP (YP) Islands Iliffe 200 Carmen described also B pressure findings incipient (YP 20 2

Abstract Despite the recent increase in knowledge about Brazilian Cladoceromorpha (Cladocera and Cyclestherida), this group of fauna is poorly known in some regions of the country, including Alagoas State. Based on the literature and a few original samples, the present paper reports 35 species of Cladoceromorpha from Alagoas, 18 of which are new records for the state. The observed taxa are illustrated. In addition, distributional and taxonomic comments on selected taxa are provided. Cladocera Cyclestherida, Cyclestherida , Cyclestherida) country State samples 3 1 state illustrated addition provided

Abstract Procambarus montebelloensis, new species, is described from Montebello lake district in Chiapas, Mexico. The new species can be distinguished from P. mirandai by a gonopod with shorter and more slender mesial process apically directed, a less pronounced cephalic shoulder and a shorter central projection. Regarding the external morphology, in the new species the anterior portion of the head is notably directed downwards, and it has a more elongated chela with a distinct dentition. montebelloensis Chiapas Mexico P projection morphology downwards dentition

Abstract A simple, cheap, and yet effective technique to allow easy mounting and imaging of small crustacean (or arthropod) limbs or appendages under the scanning electron microscope using custom-made aluminum mounts, cut from commercial aluminum cans, is explained and illustrated. simple cheap arthropod custommade custom made mounts cans illustrated

Abstract It is known that several animals are sensitive to magnetic fields. Magnetoreception in animals is the ability to sense the geomagnetic field of the Earth and to use their vectorial properties for navigation and terrestrial location. Animals can also show magneto-sensitivity, unrelated to navigation and show changes in behavior during the application of magnetic fields. The aim of the present study was to analyze the behavior of the shrimp Litopennaeus vannamei under the presence of artificial magnetic fields of different intensities under laboratory conditions. Shrimps were chosen because of their economic importance and because they have been neglected in the study of magneto-sensitivity in animals. The laboratory experiments were performed with the use of a pair of circular coils and four aquariums (three treatments and a control, with 20 shrimps each). Our results show for the first time that L. vannamei shrimps are magneto-sensitive, showing a preference to swim against the magnetic field lines direction as is done by magnetotactic bacteria from the Southern Hemisphere. Also, it was observed that the shrimps remain still after the application of magnetic field intensities from 44 to 237 µT, which could be useful for maintaining shrimps in their captive areas. location magnetosensitivity, magnetosensitivity magneto sensitivity, sensitivity conditions three control 2 each. each . each) L magnetosensitive, magnetosensitive sensitive, magneto-sensitive Hemisphere Also 4 23 µT areas

Abstract A total of 340 specimens of hermit crabs belonging to 34 species, included in four families and 10 genera were collected from the northern coast of Halmahera, in North Maluku, Indonesia. Two species are reported for the first time from Indonesia: Coenobita pseudorugosus Nakasone, 1988, and Trichopagurus macrochela Komai and Osawa, 2005. The color in life for Diogenes spinicarpus Rahayu and Forest, 1995, Diogenes foresti Rahayu and Hortle, 2002, and Clibanarius bistriatus Rahayu and Forest, 1993 is also reported for the first time. A list of hermit crabs found in northern Halmahera, including its habitat and distribution is presented here. 3 1 Halmahera Maluku Indonesia Nakasone 1988 Osawa 2005 Forest 1995 Hortle 2002 199 here 198 200 19 20 2

Abstract The poorly known xanthiform crab Pilumnus palmeri Garth, 1986, is known only from two poorly preserved specimens collected from Ecuador. Garth had only provisionally placed the species in Pilumnus Leach, 1816, and it was subsequently referred to a new genus, Garthopilumnus Števčić, 2011 and a new family Garthopilumnidae Števčić, 2011. Garthopilumnus currently sits as a valid genus within Pilumnidae Samouelle, 1819. A re-examination of the holotype male, now in poor condition, shows that it is a juvenile, and key aspects of the original figure of the species given in the account of the type are inaccurate. Given the incompleteness and immaturity of available material, we could not confidently assign the species to an existing family, but we are also not convinced a new family for the species is warranted. The morphological features of Garthopilumnus palmeri suggest it is a member of the Portunoidea, where we provisionally place it. 1986 Ecuador Leach 1816 Števčić 201 Samouelle 1819 reexamination re examination male condition juvenile inaccurate material warranted Portunoidea 198 181 20 19 18 2 1

Abstract In this study, we report six records of the non-native giant river prawn Macrobrachium rosenbergii (De Man, 1879) in the Furnas mega reservoir, state of Minas Gerais (Southeast Brazil), during continuous monitoring conducted from 2006 to 2023. All recorded specimens were males of the blue claw (BC) morphotype and possibly entered interior areas of the reservoir via accidental escapes. There was no occurrence of established populations in the region, nor any evidence of disease in the specimens obtained. However, continuous monitoring is recommended to record new escapes and determine the possibility of establishment of giant river prawn populations in the aquatic environment of the Furnas mega reservoir. study nonnative non native De Man 1879 Southeast Brazil, Brazil , Brazil) 200 2023 BC (BC region obtained However 187 20 202 18 2 1

Abstract The Gulf of California is known for its high productivity, diversity, and unique oceanography. Based on old and recent contributions, we estimate a richness of 160 copepod species in this province. This work seeks to identify latitudinal and seasonal patterns of the copepod composition, abundance, and diversity in the Gulf of California during 1985. Differences between four zones of the gulf (NGC, CGC, SGC, EGC) and between the cold and warm seasons were hypothesized, based on taxonomic and ecological data. Samples were collected during the CORTES cruises (1985), which also measured salinity, temperature, and dissolved oxygen at each station. We analyzed the latitudinal and seasonal variation of the copepod community with multivariate analyses (NMDS-PCA) and correlated these with the environmental data (CCA). Seventy-nine copepod species were identified, averaging 265,649 and 98,885 ind/10 m3 in the cold and warm seasons, respectively. Only 53 of these occurred in both seasons, indicating seasonal change in species composition. Composition and diversity varied latitudinally in the cold season (P < 0.05 in all comparisons but CGC vs. SGC), but not in the warm season (except NGC vs. the rest of the gulf). There was seasonal change in the composition and the abundance (P < 0.005 cold vs. warm season). Richness and diversity were negatively correlated with salinity (decreasing from the north of the gulf); the abundance and composition were mainly affected by the shift in temperature. These patterns also match the phytoplankton abundance and size structure in the gulf, probably the main factors affecting copepod distribution. productivity oceanography contributions 16 province 1985 NGC, (NGC SGC EGC hypothesized 1985, , (1985) temperature station NMDSPCA NMDS PCA (NMDS-PCA CCA. CCA . (CCA) Seventynine Seventy nine identified 265649 265 649 265,64 98885 98 885 98,88 ind10 ind 10 ind/1 m respectively 5 P 005 0 05 0.0 vs SGC) except gulf. gulf) 0005 0.00 season. season) decreasing distribution 1 198 (1985 (CCA 26564 26 64 265,6 9888 9 88 98,8 ind1 ind/ 00 0. 000 19 (198 2656 2 6 265, 988 8 98, (19 (1 (