Genus Hyalella Research Articles

On the presence of the epibiont (ectosymbiont) Lagenophrys lenticulata (Kellicott, 1885) (Ciliophora) on Hyalella cursvispina Schoemaker, 1942: is it possible to find it on Chilean Hyalella populations?

Abstract The amphipods of the genus Hyalella have many endemic species throughout South America, and these may have poorly studied associated species as epibionts. The aim of the present study was to review the literature on the presence of the protozoon Lagenophrys lenticulata (Kellicott, 1885) on species of Hyalella and contrast the results with the geographical distribution of the reported hosts. The literature records the presence of L. lenticulata on populations of H. azteca from Canada, Mexico and the United States of America, and on populations of H. curvispina from Uruguay. The literature also reports that H. curvispina is widespread throughout southern South America, including Argentina and Chile, and that it would be possible to find the presence of epibionts on other populations of H. curvispina. The corresponding biogeographical and evolutionary topics are discussed.

Checklist of symbionts in Hyalella (Amphipoda, Hyalellidae) from South America

Abstract Despite their ecological importance, research on symbionts of amphipods has been limited in South America. The present study provides a comprehensive overview of symbiont organisms in the freshwater amphipods of the genus Hyalella in South America. Our findings reveal various taxa such as Apicomplexa, Microspora, Peritrichia, Folliculinidae, trematodes, nematodes, cestodes and acanthocephalans, often involving complex life cycles. Studies on symbionts have been done almost exclusively in Argentinean Patagonia. The present overview allows us to know the species that use amphipods, to elucidate their lifecycles and to know their occurrence values.

Two new species of Hyalella (Amphipoda, Dogielinotidae) from the Humid Chaco ecoregion of Paraguay.

The freshwater amphipod genus Hyalella Smith, 1874 is widely distributed in the Neotropics, with several biogeographically restricted species and a high cryptic diversity throughout South America. Tens of species of Hyalella have been documented from nearby Brazil and Argentina, but no systematic record of the genus exists for Paraguay. Here we describe two new species of Hyalella: H.mboituisp. nov. and H.juliasp. nov. from the Ñeembucú wetlands of southwestern Paraguay. Hyalellamboituisp. nov. and H.juliasp. nov. are characterised by a dorsally smooth body, pigmented eyes, uropod 1 endopod with a curved seta, the dorsal margin of uropod 3 ramus without setae, and uropod 3 peduncle longer than wide and with six setae apically. The two species are distinguished by their diagnostic mouthparts, with a median serrated edge on the lacinia mobilis in H.mboituisp. nov. and two elongated lateral denticles with a serrated edge in H.juliasp. nov., and by the presence of a pronounced cup for the dactylus on gnathopod 2 in H.mboituisp. nov. In addition, they show differences in the number of articles on antennae 1 and 2, in the relative length of the pereiopods, and in the numbers and types of setae on their gnathopods and uropods 1-3. Hyalellamboituisp. nov. and H.juliasp. nov. represent the first taxonomically documented occurrence of Paraguayan freshwater amphipods. These new taxa attest to the largely unmapped species richness of freshwater invertebrates in the Humid Chaco of Paraguay. This potential biodiversity hotspot is currently under threat from land conversion, highlighting the need for more systematic studies and effective conservation of the local invertebrate biodiversity.

First reports of inland water benthic crustaceans for a Mediterranean-climate river (Claro River basin, Chile)

Abstract Existing studies on central Chilean inland waters only mention records of decapods, but there are no ecological studies about decapods and other crustacean groups. The aim of the present study was a first characterization of inland water crustaceans in Claro River, a Mediterranean-climate river from Chile. The results of redundance analysis (RDA) revealed that the crab Aegla affinis inhabits waters of high pH and low temperature values, whereas amphipods of the genus Hyalella inhabit habitats with high pH, high temperatures, and low values of dissolved oxygen. Finally, ostracods (family Cyprididae), isopods (Heterias sp.) and the southern river crayfish (Samastacus spinifrons) inhabit water systems with moderate values of pH, temperature, dissolved oxygen, and conductivity. This paper represents the first ecological report for crustaceans of central Chilean inland waters, and the results appear to be similar to comparable descriptions for northern Patagonian rivers.

Probabilistic models for understanding inland amphipods water population abundances in Andean stream (Caspana, 23°S, Antofagasta region, Chile)

Abstract The Andes mountains in northern Chile have numerous small permanent and intermittent streams that are poorly studied; among the most reported species are amphipods of the genus Hyalella, specifically H. fossamanchini and H. kochi. The aim of the present study was to do a first characterization of populations of both amphipod species in a small stream (Caspana, 23°S; 3200 m a.s.l.), that was visited in September 2022. The first results using a Kruskall-Wallis nonparametric test revealed that the abundances of both species and unidentified juveniles were not significantly different in a comparison of two sites, whereas a Mann-Wittney nonparametric U test gave similar results when each species and juveniles were compared between sites. The results of variance/mean ratio revealed the existence of an aggregated pattern, and a negative binomial distribution for all samples. The occurrence of an aggregated pattern and the consequent negative binomial distribution is a very frequent pattern for inland water invertebrates in Chilean rivers.

Two new species of Hyalella Smith, 1874 (Malacostraca: Amphipoda: Hyalellidae) from the state of Santa Catarina, Brazil.

The genus Hyalella Smith, 1874 occurs exclusively in the Americas. In Brazil, the states of Santa Catarina and Rio Grande do Sul have the largest number of records with 20 species. This paper presents two new species for the state of Santa Catarina, Brazil. The serrate setae with accessory seta, a new type of seta, is registered for the genus and observed on gnathopods 1 and 2. Additionally, microtrichs are reported on articles, a detail that has not been mentioned in previous studies. Hyalella carsone sp. nov. is characterized by gnathopod 1 with comb-scales from the basis to the carpus, gnathopod 2 dactylus with proximal margin strongly serrated and the presence of serrate setae on the articles of gnathopods 1 and 2. Hyalella wangarie sp. nov. is characterized by gnathopod 2 palm not sinuous with margin inconspicuously serrated, peduncle and inner ramus of the pleopod with simple setae, presence of curved seta on uropod 1 of male and gnathopod 1 palm on female slightly serrated. In this work we expand the number of species from Brazil and increase the morphological knowledge of the genus Hyalella.

Description of two new epigean species of the genus Hyalella S.I. Smith, 1874 (Crustacea: Amphipoda: Hyalellidae) from Jalisco, Mexico

Description of two new epigean species of the genus Hyalella S.I. Smith, 1874 (Crustacea: Amphipoda: Hyalellidae) from Jalisco, Mexico

Description of a new thermal species of the genus Hyalella from Peru with molecular phylogeny of the family Hyalellidae (Crustacea, Amphipoda)

In recent years, the impact of rising water temperatures associated with global warming on cold-water freshwater organisms has become a major issue, and understanding the physiological and ecological elements that support temperature limits is essential for the conservation biology of freshwater organisms. We describe a new species of thermophilic hyalellid amphipod, Hyalella yashmara sp. nov. from the Peruvian hot spring Baños del Inca Cajamarca and this could potentially contribute to understanding the high temperature preference of these. We found that this new species can live in water temperatures ranging from 19.8 to 52.1°C, that, to our knowledge, is the highest recorded habitat temperature of amphipods. Hyalella yashmara sp. nov. is most similar to H. meinerti Stebbing, 1899 from Peru. However, this new species differs from the latter in features of gnathopods 1 and 2, sternal gills, uropod 3 and telson. A detailed morphological comparison between Hyalella yashmara sp. nov. and Peruvian species is also provided. Our molecular phylogenetic analyses based on the nuclear 28S rRNA and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences strongly support the monophyly of Hyalellidae (=Hyalella). Since Hyalellidae was found to form a sister group with Chiltoniidae, these two families were expected to have originated from a common ancestor that invaded freshwater habitats from marine environments when the continents of South America, Africa and Australia were united as Gondwana. Our findings suggest that the South American species of Hyalella are not monophyletic and that the North American species are likely to share a most recent common ancestor with H. yashmara sp. nov. ZooBank: urn:lsid:zoobank.org:act:190CFB16-7BE4-4786-A97F-0AFD8CD72DEA

Hyalella luciae (Crustacea, Amphipoda, Hyalellidae)a new species of freshwater amphipod from Southern Brazil.

Currently, the freshwater amphipod Hyalella Smith, 1874 includes 91 valid species distributed only in the Americas. This study describes the fifth species for the Vrzea River basin, located in the northwestern region of the state of Rio Grande do Sul, Southern Brazil. Among its most prominent features are the presence of the curve seta on the inner ramus of uropod 1 of the males, sternal gills on segments 2-7, propodus ventral face of the gnathopod 1 with nine serrate setae and several small simple and triangular setae, peduncle of uropod 3 with 11-12 distal cuspidate setae with accessory setae, and telson with fifteen cuspidate setae with accessory setae distributed on distal margin. This study presents a detailed comparison of the species we are describing with those already discovered. The diversity of freshwater amphipods in southern Brazil is intriguing. Further investigations should open the way to elucidate the evolutionary history of these crustaceans, uncovering the potential and patterns of diversification of the genus Hyalella.

First island species of Hyalella (Amphipoda, Hyalellidae) from Florianpolis, state of Santa Catarina, Southern Brazil.

The Hyalella comprises a group of freshwater amphipods endemic to the Americas. In Brazil, the greatest diversity of species known so far is concentrated in the state of Rio Grande do Sul, but recently discoveries were made in the neighboring state of Santa Catarina. The present work describes the first island species of the genus Hyalella in Brazil and the fifth with occurrence in the state of Santa Catarina. The species was found in streams of two watersheds, located at the Monumento Natural Municipal da Lagoa do Peri, an important environmental protection area on the island of Florianpolis, Southern Brazil. Hyalella insulae n. sp. shows the following characters: inner face of propodus of gnathopod 1 with 7 serrate setae, gnathopod 2 with propodus ovate, peduncle of uropod 3 with 10 cuspidate setae, telson rectangular, wider than long, with 6 cuspidate setae and 2 plumose setae laterally close to each distal seta. H. insulae n. sp. differs from the other species with occurrence in Santa Catarina, H. catarinensis, H. rioantensis, H. sambaqui and H. lagoana, mostly concerning to the number and shape of setae of the gnathopods, uropods and telson. A comparison was also made with species from the neighboring states, Rio Grande do Sul and Paran. The description of H. insulae n. sp. in the present study contributes to increasing the knowledge of the Hyalella diversity in the state of Santa Catarina, little known so far.

Diversity and distribution of the genus Hyalella (Crustacea: Amphipoda: Hyalellidae) in temporary wetlands from the southern Brazilian Coastal Plain, with a taxonomic key to the species in the region

ABSTRACT The knowledge of the diversity and distribution of Hyalella species is scarce in the subtropical regions of Brazil. The present study investigated the diversity and distribution of Hyalella species in subtropical temporary wetlands in the southern Brazilian Coastal Plain. Six species were registered in the study region, including three new species of the genus. The spatial distribution of the species in the study region suggests that the hydrographic region (or freshwater ecoregion) is an important driver of the geographic distribution of the species. Thus, the present study increases to 19 the diversity of species with distribution in the southern region, with one new record for the state of Santa Catarina, one for the state of Rio Grande do Sul, and one for both states. We also expanded the distribution ranges of H. bonariensis, H. castroi, and H. kaingang. In addition, we elaborated a taxonomic key to the species of Hyalella known to southern Brazil. Thus, we demonstrate the need for more taxonomic studies to better understand the diversity of macroinvertebrates in Brazilian wetlands, in order to protect our fauna and contribute to the development of future conservation policies.

A new species of freshwater amphipod (Crustacea, Peracarida, Hyalellidae) from Southern Brazil

The freshwater amphipod of the genus Hyalella is typical from continental American waters and shows high levels of endemicity and Brazil has the second largest diversity. A new species is described here, Hyalella longipropodus n. sp. that occurs in a spring of southern Brazil in the municipality of Palmeira das Misses, in the northwestern region of state of Rio Grande do Sul, southern Brasil. Hyalella longipropodus n. sp. shows the following character states: antenna 2 more than half body length, gnathopod 2 propodus elongated, uropod 1 inner ramus of male without apical curved setae, uropod 3 peduncle with seven strong distal setae with accessory setae, ramus of uropod 3 with ten cuspidate setae with accessory setae. Hyalella longipropodus n. sp. occurs in sympatry with H. gauchensis, but these differ especially in the size and shape of gnathopod 2, the presence of curved setae on uropod 1 in H. gauchensis and the absence in H. longipropodus n. sp., antenna length (longer in H. longipropodus n. sp.) and number of cuspidate setae on uropods 1, 2, and 3. Besides the morphological differences, H. longipropodus n. sp. presented genetic differences always above 19% for the COI gene and 29 % for the 16S rRNA gene, when compared with other species found in the northwestern region of the state of Rio Grande do Sul, showing that it is really a species not yet described by science.

Comparative Mitogenomics in Hyalella (Amphipoda: Crustacea).

We present the sequencing and comparative analysis of 17 mitochondrial genomes of Nearctic and Neotropical amphipods of the genus Hyalella, most from the Andean Altiplano. The mitogenomes obtained comprised the usual 37 gene-set of the metazoan mitochondrial genome showing a gene rearrangement (a reverse transposition and a reversal) between the North and South American Hyalella mitogenomes. Hyalella mitochondrial genomes show the typical AT-richness and strong nucleotide bias among codon sites and strands of pancrustaceans. Protein-coding sequences are biased towards AT-rich codons, with a preference for leucine and serine amino acids. Numerous base changes (539) were found in tRNA stems, with 103 classified as fully compensatory, 253 hemi-compensatory and the remaining base mismatches and indels. Most compensatory Watson–Crick switches were AU -> GC linked in the same haplotype, whereas most hemi-compensatory changes resulted in wobble GU and a few AC pairs. These results suggest a pairing fitness increase in tRNAs after crossing low fitness valleys. Branch-site level models detected positive selection for several amino acid positions in up to eight mitochondrial genes, with atp6 and nad5 as the genes displaying more sites under selection.

A new species of the genus Hyalella (Crustacea, Amphipoda) from northern Mexico.

A new species, Hyalella tepehuanasp. nov., is described from Durango state, Mexico, a region where studies on Hyalella have been few. This species differs from most species of the North and South American genus Hyalella in the number of setae on the inner plate of maxilla 1 and maxilla 2, characters it shares with Hyalella faxoni Stebbing, 1903. Nevertheless, H. faxoni, from the Volcan Barva in Costa Rica, lacks a dorsal process on pereionites 1 and 2. Also, this new species differs from other described Hyalella species in Mexico by the shape of the palp on maxilla 1, the number of setae on the uropods, and the shape of the telson.

First record of the genus Hyalella (Amphipoda: Hyalellidae) from Santa Catarina State, Brazil, with description of two new species

Abstract: The amphipod HyalellaSmith, 1874 is exclusive to the Americas, and the South region of Brazil presents the greatest diversity of the genus. This paper presents two species of Hyalella from Santa Catarina state, Brazil. A new species from the municipality of Palmeira is characterized by oval eyes, absence of flanges, epimeral plates not accuminated, presence of three lateral pappose setae on article 4 in antenna 2, absence of plumose setae in the maxilliped, presence of comb-scales and absence of serrate setae in the gnathopods, presence of curved seta on the inner ramus of the uropod 1 and absence of lateral setae on the telson. A new species from Rio das Antas municipality main characteristics are absence of flanges, epimeral plates accuminated, absence of plumose setae and distal nail in the maxilliped, presence of comb-scales and absence of serrate setae in gnathopods, presence of curved seta on the inner ramus of the uropod 1 and absence of lateral setae on the telson. Here we expand the distribution and increase the morphological and taxonomic knowledge of the genus.

A new species of Hyalella Smith, 1874 (Crustacea: Amphipoda: Hyalellidae) from Oklahoma, USA.

The genus Hyalella is endemic to the North and South America. There are currently 14 species described in North America and the Caribbean. For a long time, it had been assumed that different populations of these animals represented a single species, Hyalella azteca (Saussure, 1858). However, molecular analyses have demonstrated H. azteca sensu lato to be a complex of multiple species, so some species that occur in the United States have been mistakenly identified. Our aim in this paper was to describe a new species of Hyalella, found in Oklahoma, USA. The new species can be differentiated from the others, mainly because it presents serrated setae in the maxilla 2, because it does not have flanges on the surface of the body, presents the palm of the gnathopod 2 of the same size as the distal-posterior margin of the propodus, by shape and number of setae on the uropod 3 and telson. The description of this new species of Hyalella increases to 15 the number of species of the genus for the USA. It is important to understand the diversity of Hyalella with consideration of their possible role as bioindicators of environmental quality, and further consideration of their conservation status, and especially for species known from a single spring.

A new species of the Hyalella 'azteca' complex (Crustacea: Amphipoda: Hyalellidae) from Florida.

Examination of material from the Wakulla River in north-western Florida revealed the presence of a new species of the amphipod genus Hyalella. It appears to be most closely related to H. azteca (Saussure) sens. strict., but can be distinguished by the nature of maxilla 1 and the telson. The setation of uropod 3 has been given systematic importance for this genus, but we show in the present paper that this character exhibits high intraspecific variation, even within the same individual. This is the first formally described species of Hyalella from Florida.

Ecological aspects of natural populations of Hyalella pampeana (Crustacea, Amphipoda, Hyalellidae) from the Natural Reserve Island of Martín García (Río de La Plata, Argentina).

Freshwater amphipods of the genus Hyalella have a great importance in aquatic ecosystems due to their role in matter and energy cycling and its utilization as bioindicators of environmental health. The aim of this work was to analyze relevant population parameters of Hyalellapampeana, such as population density and structure, individual body size, sex ratio, fecundity and recruitment, and to study the possible relation of these parameters to variations in environmental variables. Samples were taken monthly during a one-year period (2006) at three small ponds in the Natural Reserve Island of Martín García, Argentina. The inland aquatic environments showed distinctive physicochemical characteristics, mainly related to pH and conductivity values. Amphipod population density varied among sites and throughout the year, with population peaks during spring, positively correlating with pH values. The operational sex ratio of the total population was almost equal to 1 male: 1 female, displaying seasonal variation. Mean fecundity and mean size of ovigerous females were higher during winter and early spring months than in summer months. The presence of ovigerous females and juveniles in all months indicated that reproduction is continuous during the year for Hyalella, in its natural environment.

Reproductive aspects of Hyalella carstica (Amphipoda: Hyalellidae) in a natural environment in southeastern Brazil

The reproductive aspects of populations are important determinants of their ability to maintain themselves throughout time. In the case of amphipods from the genus Hyalella Smith, 1874, the reproductive period is easily determined by the presence of ovigerous females and pre-copula pairs in the population. This study evaluated the fecundity, pairing patterns and reproduction period of Hyalella carstica Bastos-Pereira and Bueno, 2012 in a karst environment in the West of Minas Gerais, Brazil. Monthly, from April, 2010 to April, 2011, amphipods were sampled using a hand net with 15 cm diameter and 250 µm mesh size. In the laboratory, animals were sexed and measured, and the ovigerous state of females was evaluated. Couples in pre-copula and ovigerous females were found throughout the year, with the exception of the dry months (September−November). During drought, the stream's superficial water dried out, and only a few refuges for the population remained. Although couples were found in all months with a water flow, a higher number of unpaired males and females was found after the dry season. In all months, ovigerous females were more abundant than non-ovigerous, and the relationship between head length and the number of eggs in the marsupium was positive. Most eggs were in the first developmental stage, although all other stages were found before the dry season. Considering the frequency of pre-copula pairs, as well as ovigerous females, the reproduction in this H. carstica population seems to be continuous throughout the year, without a distinct peak.

An empirical test of stable species coexistence in an amphipod species complex.

The ability of phenotypically similar species to coexist at local scales is paradoxical given that species that closely resemble each other should compete strongly for resources and thus be subject to competitive exclusion. Although theory has identified the key requirements for species to stably coexist, empirical tests of coexistence have rarely been conducted. We explored a key requirement for species to stably coexist: a species can invade a community when it is initially rare. We also assessed whether primary productivity (manipulated using phosphorus availability) affected invasion success by increasing the amount of resources available. Using two mesocosm experiments and an assemblage of phenotypically similar amphipod species in the genus Hyalella, we found no evidence for invasion success among the three Hyalella species. Further, patterns of species exclusions differed among the species, which suggests that one species is an especially poor competitor. Finally, these patterns were consistent regardless of whether mesocosms were fertilized with low or high levels of phosphorus. Our results, suggest that species differences in resource competition and predator avoidance ability found in previous studies using these Hyalella species may not be sufficient to allow for coexistence. Moreover, our study demonstrates the importance of using a variety of empirical approaches to test species coexistence theory.