Morphometric analysis of Littoraria angulifera (Caenogastropoda) in estuarine regions of northeastern Brazil

Abstract

<jats:p>Abstract The gastropod Littoraria angulifera (Littorinidae) is an exclusively estuarine mollusk with Neotropical anfiatlantic distribution. Recent studies indicate a possible use of the species as bioindicator. The aim of this study was to analyze the shell height, as well as to perform a morphometric analysis of the reproductive apparatus of L. angulifera collected in 22 sampling points located between latitudes 13º54'S and 15º44'S in the South Atlantic, State of Bahia, Northeastern Brazil. The specimens were obtained in different estuarine environments including mangroves, as well as on rocks and concrete walls in places close to ports, shipyards and berths during January and February 2014. All specimens (n = 880) were analyzed regarding the sex and shell height/morphology, 440 were analyzed about the reproductive apparatus morphometry and 15 in histological description. The average shell height of animals from artificial substrates in nautical areas was lower (p&lt;0.05) than the animals from mangroves, mainly in preserved areas, evidencing relation with human impacts and desiccation. The morphometric analysis of L. angulifera reproductive tract allowed us to conclude that the length of prostate in males and of palial oviduct in females may be useful in the reproductive evaluation of the species.</jats:p>

The Mangrove Periwinkle Littoraria angulifera (Mollusca: Littorinidae) in the Urabá Gulf (Colombian Caribbean): Finding Ways in an Urbanizing Coast?

“…Hence, an alternative hypothesis to explain the smaller size range of L. angulifera in urban anthropogenic substrates would be that it represents an urban signature of phenotypic change, as reported for many various marine species elsewhere (Alberti, 2015;Alberti et al, 2020). First, a significantly smaller shell length has been here reported for L. angulifera populations inhabiting urban anthropogenic substrates as compared with populations in mangrove forests studied in the Brazilian states of Espírito Santo (Costa et al, 2013) and Bahía (Zeidan et al, 2020), suggesting that shifts to smaller body sizes are related to urbanization. Second, mangrove clearing has been empirically related to increased temperature in both water and sediment matrices (Granek and Ruttenberg, 2008;Kon et al, 2010) and temperature is higher in intertidal artificial structures than in natural adjacent habitats (Aguilera et al, 2019).…”

“…We could not rule out this possibility from our snapshot samplings, but L. angulifera -as most tropical mollusks dodisplay a continuous reproduction and hence populations are not commonly dominated by clearly defined cohorts (Urban and Riascos, 2001;Boehs and Freitas, 2021). Indeed, it was precisely the observed persistence of a population thriving in artificial substrates in Turbo and elsewhere through the distribution range (Gallagher and Reid, 1979;Costa et al, 2013;Zeidan et al, 2020) was what motivated this study. Hence, an alternative hypothesis to explain the smaller size range of L. angulifera in urban anthropogenic substrates would be that it represents an urban signature of phenotypic change, as reported for many various marine species elsewhere (Alberti, 2015;Alberti et al, 2020).…”

“…It is therefore a remarkable finding that the relative abundance of L. angulifera was one or two orders of magnitude higher in its southernmost, urbanized and osmotic-limiting boundary than in remnant mangrove patches or in woody debris at sandy beaches. Although the fossil evidence and a molecular phylogenetic reconstruction of ancestral habitats indicate that L. angulifera is an obligate mangrove dweller (Reid et al, 2010), several studies have reported this species thriving in hard natural or artificial substrates (e.g., Gallagher and Reid, 1979;Janson, 1985;Antwi and Ameyaw-Akumfi, 1987;Reid and Mak, 1999;Costa et al, 2013;Zeidan et al, 2020). Thus, this may be thought of as a sign of contemporary habitat diversification -likely reflecting on-going coastal urban sprawland the outstandingly high abundance of L. angulifera suggest that hard artificial substrates are not necessarily low-quality habitats when compared with core mangrove habitats outside the Urabá Gulf.…”

“…Accordingly, shell morphological variation of L. angulifera and other species in the genus has been related to local differences in forests conditions, including canopy height, food availability, average rainfall, and temperature (Merkt and Ellison, 1998;Tanaka and Maia, 2006;Riascos and Guzman, 2010;Silva et al, 2013). These ecological traits suggest that L. angulifera operates as a mangrove specialist, but an increasing number of studies show that it may actually occupy anthropogenic habitats (Gallagher and Reid, 1979;Costa et al, 2013;Zeidan et al, 2020) and display a high phenotypic plasticity (Janson, 1985;Reid and Mak, 1999); two traits typically observed in generalist species (Duarte et al, 1995).…”

Molecular Phylogenetics of Physa acuta (Pulmonata: Basommatophora): an Invasive species in Central Punjab Pakistan

“…Certain snail species are bioindicators (Zeidan et al, 2020) however Physa is cosmopolitan in distribution (Albrecht et al, 2009;Altaf et al, 2017d). These snails are found in large number in the humid season i.e.…”