Grooming behaviour and the morphology of grooming appendages in the endemic South American crab genus Aegla (Decapoda, Anomura, Aeglidae)

The pereiopods (walking legs) of crustaceans have been shown to have both mechano- and chemosensory functions including: detecting various odors, mechanical stimuli, as well as being used for grooming of gills and brood care. Using scanning electron microscopy, we examined the pereiopods of reproductive male (form I) and reproductive female (glair) crayfish Orconectes rusticus Girard, 1852 and found that the distal portion (dorsal surface) of the propodus of pereiopods 2 through 5 contain smooth, plumose, serrate and cuspidate setae. Various studies have implicated both smooth and serrate setae as being important for grooming; therefore, we used scanning electron microscopy to examine and compare the distribution of smooth and serrate setae on the pereiopods of reproductive male and female crayfish in order to determine if there were differences between sexes. We found that there were no differences in the number of tufts (pockets) or number of smooth setae on the second and third pereiopods (chelipeds) between male and female crayfish. Further, the second and third pereiopods of both male and female crayfish had significantly more smooth setae than the fourth and fifth pereiopods. When the distribution of serrate setae was compared, we found that reproductive female crayfish possess significantly more serrate setae on their fifth pereiopods than their fourth pereiopods and both pereiopods 4 and 5 of form I male crayfish. Overall, increases in serrate setae on the fifth pereiopods of reproductive female crayfish are significant. We suggest that female crayfish may use serrate setae of the fifth pereiopods extensively for grooming eggs and brood care during reproduction.

Respiration, sensory input, movement, and molting rely on crustacean body regions being free of fouling. While the grooming appendages of shrimps have been described, few studies have documented the functional morphology of grooming appendages in brachyuran crabs. Because shrimps and brachyurans have very different body morphology and grooming behaviors, their grooming setae may vary. The morphology of grooming appendages of blue (Callinectes sapidusRathbun, 1896) and stone (Menippe mercenaria (Say, 1818)) crabs were investigated to gain better insight into their efficiencies in decreasing fouling. Callinectes sapidus is an active swimmer, migrates through currents across estuaries, spends less time grooming, and is exposed to more environmental variants in contrast to M. mercenaria, which has a lower activity level and spends more time grooming. To compensate for this higher activity level and lower grooming time budget, C. sapidus was predicted to have more setal types on its grooming appendages as compared to M. mercenaria. Thirteen different body appendages/regions involved in grooming are described in both species by using scanning electron and light microscopy. We documented the morphology, presence or absence of setal patches, and types of setae in 104 different grooming appendages and groomed body regions. Of 25 types of setae, nine are unique to C. sapidus, rejecting the hypothesis that C. sapidus have more diverse grooming setae. Menippe mercenaria has denser setal patches and less fouling than C. sapidus. Nine new setal types are described. Fouling, setal diversities, and functions that correspond to grooming behaviors are discussed.

In crustaceans, grooming behaviors decrease fouling by removing debris from the exoskeleton and body structures; these grooming behaviors improve respiration, sensory reception, movement, and reproduction. Setal morphologies of the following grooming appendages in the decapod crustacean spider crab Libinia dubia are examined including the first pereiopod (cheliped), first, second, and third maxillipeds (mouthparts), and first, second, and third epipods (internal extensions of the maxillipeds). The objective of this study was to describe setal morphologies of these grooming appendages and to elucidate possible functions and efficiencies of setal structures. Spider crabs are hypothesized to have elaborate setal morphologies, mainly for cleaning specialized decorating setae as well as for cleaning inside the gill chamber, which has a higher likelihood of becoming fouled compared to other decapods such as shrimps. Fourteen setal types are documented and included several varieties of serrate and pappose setae as well as simple setae, cuspidate setae, papposerrate setae, and canoe setae. Maxillipodal epipods in the gill chamber are free of fouling, suggesting the setation on the third maxilliped protopod has an efficient functional morphology in removing debris before water enters the gill chamber. Serrate setae may function for detangling and separating structures whereas pappose setae may function for fine detailed grooming. The cheliped is the only grooming appendage that can reach decorating setae and it contains only pappose setae; thus decorating setae is not likely groomed in a manner that would greatly decrease fouling. J. Morphol. 277:1045-1061, 2016. © 2016 Wiley Periodicals, Inc.

Qualitative and quantitative observations on G. oerstedii show that its grooming behavior consists (in order of decreasing frequency) of antennae (Al and A2), eye, subcarapace, gill, and general body grooming. As in decapod crustaceans, there is an inverse relationship between bout frequency and bout duration of grooming behaviors in this stomatopod. The only appendage observed in grooming, the first maxilliped, has grooming brushes of rasp, multiscaled, and scaled serrate setae; the microstructure of these setae is described and illustrated with SEM. In the Stomatopoda, low diversity of specialized grooming structures reflects a conservative stomatopod body plan, while the high diversity of cleaning characters in the Decapoda reflects the group's high variation in body morphology. Analysis of the functional morphology of G. oerstedii's fifth maxilliped (M5) propodal brush suggests that it is a reduced and vestigial grooming character. It is concluded that a vestigial M5 grooming brush is a synapomorphy that supports the hypothesis by Jacques (1983) that the Gonodactylidae, Odontodactylidae, and Protosquillidae are closely related. Amputation experiments were performed to test the hypothesis that grooming behavior is an antifouling adaptation. Members of the experimental group had the first maxillipeds amputated; in control groups, exopods of the third pereiopods, a nongrooming appendage, were ablated. Experimental and control animals were exposed to fouling on sea-water tables for 2 weeks. Fouling was quantified by counting strands of Leucothrix, a filamentous bacterium. Both gill filaments and antennular aesthestascs of experimental (nongrooming) stomatopods were heavily fouled by Leucothrix and other bacterial growth after 2 weeks, while those of controls remained clean. The low fouling on eyes and lack of fouling on most other body surfaces in experimentals raises the possibility that some parts of the exoskeleton may be protected from microbial fouling by the secretion of antifouling compounds.

Clusters of specialized serrate setae in patches called "carpal cleaning brushes," or carpal-propodal brushes, are found on the distal margins of the chelipedal carpus in many species of caridean shrimps and other decapod crustaceans. These brushes, used to clean the antennal flagellum, occur in some bresiliid shrimp species associated with hydrothermal vents in the Pacific and Atlantic oceans, and recently their presence has been proposed as a distinguishing taxonomic character at the genus level. Occurrence of such brushes in shrimp that live near hydrothermal vents is of interest because of the high number of bacteria associated with these vents. These shrimp have the potential to be heavily fouled with bacteria, whereas at the same time preliminary studies suggest that they may depend upon these bacteria at least in part (or possibly exclusively) for food. We employ scanning electron microscopy to examine and describe the general morphology and location of carpal brushes on the chelipeds of all known species in two vent shrimp genera, Rimicaris Williams and Rona and Chorocaris Martin and Hessler. The brush is well developed and clearly delimited in all known species of Chorocaris, where it consists of a triangular field of serrate setae and a posterior blunt spine that possibly functions as a "stop" to keep the antennal flagellum in place during grooming. Rimicaris exoculata has no recognizable carpal cleaning brush or any serrate setae on the chelipedal carpus and thus appears derived relative to species of Chorocaris with regard to this feature. A newly described species, R. aurantiaca, is somewhat intermediate, having no carpal brush but with two serrate setae and a blunt spine in the region occupied by the brush in species of Chorocaris. Possible implications and comparisons to the genera Alvinocaris and Opapaele are discussed briefly. J. Morphol. 235:31-39, 1998. © 1998 Wiley-Liss, Inc.

A new species of Scutalus Albers, 1850 (Gastropoda: Bulimulidae), Scutalus chango sp. n., is described from a coastal area of northern Chile. Empty shells of this new species were found buried in sand and under boulders and rocks in the foothills of the Chilean Coastal Range at Paposo, Región de Antofagasta. This new species is distinguished from all other Chilean terrestrial snails by its slender shell with a flared and reflected aperture, and by the presence of a columellar fold. This is the first record of Scutalus in Chile, and the southernmost record for this endemic South American bulimulid genus. The presence of this species in Paposo highlights the need for further research and for conservation guidelines in coastal areas of northern Chile, which have comparatively high levels of biodiversity and endemism.

Occurrence of Dicolpomys (Echimyidae) in the late Holocene of Argentina: The most recently extinct South American caviomorph genus

Revealing the cryptic diversity of the widespread and poorly known South American blind snake genus<i>Amerotyphlops</i>(Typhlopidae: Scolecophidia) through integrative taxonomy

The elaboration of a comprehensive database about the distribution of the South American genus Nassauvia has allowed investigate its conservation biogeography. The combined use of historical (Dispersal Vicariance Analysis) and ecological (UPGMA) biogeographical approaches has led to detecting past, present and future critical areas in the evolution and persistence of the genus. According to the size of distribution areas, number of locations, environmental niche models, and predicted shifts of these spatial characteristics following the Intergovernmental Panel on Climate Change forecasts for the next decade, it has been possible to award the level of global and national risk for all species of the genus and assign their corresponding IUCN categories. Severe gaps in legal and in situ conservation policies have been detected within the region, making it urgent the adoption of measures aimed at preventing the extinction of the most endangered species. We identify a future dramatic loss of Nassauvia species in the Andes and conversely a species increase in Patagonia. Patagonia has emerged as the cradle of the genus and could be its refuge in the future according the predictions targeted by climate change.

A monotypic South American genus Micreurygenius Pic, 1942 (hitherto in Eurygeniinae LeConte, 1862) is synonymized with Ischyropalpus La Ferté-Sénectère, 1849 (Anthicini Latreille, 1819) and, accordingly, moved to Anthicinae Latreille, 1819. A new combination is proposed for its only known species, Ischyropalpus angustatus (Pic, 1942) comb. nov., the species is herein tentatively attributed to the I. eryngii Werner, 1966 informal species-group. The Lemodinae Matthews, 1987 is synonymized with Copobaeninae Abdullah, 1969 and Copobaenus Fairmaire & Germain, 1863 is found congeneric with Trichananca Blanchard, 1891 syn. nov. based on adult morphology. New combinations are proposed for species hitherto attributed to Trichananca Blackburn, 1891: Copobaenus apterus (Lea, 1922) comb. nov., C. bicoloratus (Gemminger in Gemminger & Harold, 1870) comb. nov., C. cheesmanae (Telnov, 2019) comb. nov., C. concolor (King, 1869) comb. nov., C. frenchi (Pic, 1913) comb. nov., C. fulgidus (Werner & Chandler, 1995) comb. nov., C. hornabrooki (Uhmann, 1995) comb. nov., C. inexpectatus (Telnov & Degiovanni, 2021) comb. nov., C. marziae (Moore & Vidal, 2005) comb. nov., C. micromelas (Lea, 1922) comb. nov., C. neotropicus (Telnov & Degiovanni, 2021) comb. nov., C. nigripennis (Lea, 1917) comb. nov., C. novacaledonicus (Telnov, 2019) comb. nov., C. pisoniae (Lea, 1917) comb. nov., C. poggii (Telnov & Degiovanni, 2021) comb. nov., C. poqui (Guerrero & Diéguez, 2018) comb. nov., C. rugulosus (Uhmann, 2007) comb. nov., C. uniformis (Lea, 1922) comb. nov., C. valenciai (Moore & Vidal, 2005) comb. nov., C. victoriensis (Blackburn, 1891) comb. nov., C. vinctus (Erichson, 1842) comb. nov. Copobaenus erratus sp. nov. from Chile is described. The Eurygeniinae LeConte, 1862 tribe Ictistygnini Borchmann, 1936 is found contribal and is synonymized with Eurygeniini LeConte, 1862 based on adult morphology. An updated key to Eurygeniinae LeConte, 1862 tribes is presented. Setosicornia Pic, 1911, an obscure monotypic South American tenebrionoid genus, is redescribed and moved to the anthicid tribe Eurygeniini (Eurygeniinae) from Ripiphoridae Laporte 1840. A monotypic South American genus Atenizoides Gilmour, 1968, originally placed in Cerambycinae Audinet-Serville, 1832 (Cerambycidae Audinet-Serville, 1832), and placed in the Eurygeniini by Phillip and Ivie (1989), is found to be congeneric with Setosicornia and a new generic synonym is introduced. A new combination is proposed for its only known species, Setosicornia curacaoae (Gilmour, 1968) comb. nov., and this species is redescribed herein.

A molecular and morphological phylogenetic analysis of South American Podocominae is herein performed. Taxa of both South American and Australasian Podocominae as well as members of other subtribes of Astereae were included in the analyses. Sequence data from the nuclear internal transcribed spacer (ITS), and the plastid trnL–trnF intergenic spacer regions were used in the molecular analysis to assess relationships among the South American genera of Podocominae. The trnL–trnF intergenic spacer provided only six informative characters. In contrast, the ITS region was more variable. Our results showed that: 1) neither the South American genera of Podocominae nor the whole subtribe Podocominae are monophyletic; 2) South American and Australasian genera, initially placed in the subtribe Podocominae on the basis of morphological characters, show no evidence of close relationship in our phylogenetic analyses based on molecular data; 3) Our results do not confirm Podocoma in its current concept as monop...

Freshwater decapod crustaceans are often ecologically important keystone species in their habitats. The freshwater hillstream decapods of Shenzhen City, Guangdong, China, were systematically surveyed for the first time from June to September 2019. We identified a total of 19 decapod species from 10 genera and six families. Of these, one Macrobrachium species and one potamid species could not be assigned to any known species. The latter clearly belongs to the monotypic genus Megapleonum Huang, Shih & Ahyong, 2018, and resembles the type species M. ehuangzhang in general external morphology. Striking differences in male gonopodal morphology along with genetic evidence based on mitochondrial 16S rDNA sequences strongly suggest that this species is distinct from the type species and it is herein described as Megapleonum shenzhen n. sp. Our survey data sheds light on the biodiversity of hillstream decapods in Shenzhen and highlights areas of conservation interest.

ABSTRACTAimThe climatic oscillations of the glacial–interglacial cycles significantly influenced species diversification, playing an essential role in shaping the current patterns of biodiversity. However, the effects of the Pleistocene climate on species diversification and their current distribution are poorly understood for the Southern Hemisphere and some taxonomic groups, such as invertebrates. Here, we explore the role of Pleistocene climate changes in the diversification and distribution of four species of South American freshwater crustaceans.LocationSouthern South America.TaxonGenus Aegla (Aeglidae).MethodsWe performed phylogenetic analyses, estimated genetic diversity and neutrality indices for Aegla alacalufi, Aegla neuquensis, Aegla platensis and Aegla uruguayana using nuclear and mitochondrial sequences. We used the mitochondrial genes to estimate divergence times, calculate historical demography and reconstruct the ancestral area range. We also estimated current and past potential distributions using ecological niche modelling.ResultsAlthough all species studied had their diversification influenced by Pleistocene glacial cycles, the Patagonian species A. alacalufi and A. neuquensis, which were directly influenced by the glacial ice cap, appear to have benefited from lower sea levels and melting of glaciation ice. As for the species A. platensis and A. uruguayana, their diversification was affected by the dry and cold climate on the continent during the glacial period.Main ConclusionsOur study unveils the intricate interplay between Pleistocene climatic fluctuations and the evolutionary history of freshwater crustaceans in South America. Distinct phylogeographic patterns were observed in Aegla. Some underwent significant diversification due to glaciation, while the cold, arid conditions of the continent shaped others. These findings underscore the crucial role of past climate dynamics in the distribution and genetic diversity of species. As freshwater ecosystems confront escalating threats, our study highlights the urgency for conservation measures and continued research to unveil species' adaptive mechanisms in the face of climate change.

During a survey of the epipelagic zooplankton carried out off the coast of the Mexican states of Jalisco and Colima, in the Eastern Tropical Pacific, female and male specimens of the poorly known calanoid copepod Pontellopsis lubbockii (Giesbrecht, 1889) were collected. Because previous descriptions and illustrations are largely incomplete and have caused some taxonomical confusion, this species is fully redescribed from specimens from the Mexican Pacific. The species has some characters that have been overlooked, but those related to the female genital double-somite are the most striking, it has two conical dorsal protuberances and a long ventral spiniform process unique of this species. The mouthparts of this species have not been hitherto described and figured, the flexible terminal setae of legs 3 and 4 is noteworthy. The male general morphology agrees in general with previous data, but new details of the leg 5 and geniculate antennule are added. Its mouthparts, with strong, serrate setae on the maxillae and maxillules, and a strong mandibular edge, suggest that this is a predator form. A dichotomous key for the identification of males and females of the species of Pontellopsis known from the Eastern Tropical Pacific is included.

Recent published molecular analyses have shown that the genus Polycarpon is polyphyletic and includes only the members belonging to the Polycarpon tetraphyllum aggregate. Morphologically, dehiscence of the capsule by valves that elastically roll inwards and eject the seeds provides a clear synapomorphy for Polycarpon in this restricted sense. Among the excluded taxa, the South American P. anomalum, P. suffruticosum and P. coquimbense are not described taxonomically, although molecular and morphological evidence exists. We here propose to recognise these species as a new South American endemic genus (Augustea gen. nov.) with three recognized species. The names Polycarpon suffruticosum (var. suffruticosum, and var. virens), P. australe, and P. anomalum are lectotypified. A diagnostic key is provided, as well as descriptions, ecological information and distribution for each species.