Anatomy and shell shape variability in a land snail Bostryx torallyi (Stylommatophora: Bulimulidae)

Introduction: The gastropod Bostryx torallyi shows high variability in shell shape and coloration. Subspecies of this organism have been described based on shell characters but, since they were slightly different, they were synonymized afterwards. Until now, shell variability has been analyzed only descriptively and its anatomy is still unknown. Objective: In this study, I provide anatomical information of B. torallyi and apply a geometric morphometric analysis to evaluate the shell shape variation among specimens. Methods: To accomplish this, type material and numerous lots were examined and dissected out. Additionally, relative warp analysis, based on 9 landmarks in ventral view of the shell, was performed using 80 specimens of 9 localities from Bolivia and Argentina. Results: According to our results, geometric morphometrics is a suitable method to evaluate differences in shell shape among localities; for instance, distinctions in the shell were noticeable between gastropods of low and high altitudes. On the other hand, it was established that the coloration of this species is independent of large-scale factors since the examined specimens came from environments with similar conditions. Furthermore, the sculpture of the protoconch and anatomy of B. torallyi coincided with the other Argentinian species of the genus. Conclusions: Therefore, I concluded that a geometric morphometric analysis of shell shape is a good complement to traditional qualitative description of the characteristics of the shell in this species.

Introducción: El gasterópodo Bostryx torallyi exhibe una gran variabilidad en la forma y coloración de su concha. Subespecies de este organismo han sido descritas con base en los caracteres de la concha; pero, dadas las sutiles diferencias, fueron luego sinonimizadas. Hasta el momento, la variabilidad de la concha ha sido analizada solo descriptivamente y su anatomía es aún desconocida. Objetivo: En este estudio, los objetivos fueron:proveer información anatómica de B. torallyi y usar un análisis de morfometría geométrica para evaluar la variación de la forma de la concha entre especímenes. Métodos: Para ello, se examinó y disectó material tipo y numerosos lotes. Adicionalmente, se realizaron análisis del "relative warp", basados en nueve "landmarks" en vista ventral de la concha, empleando 80 especímenes de nueve localidades de Bolivia y Argentina. Resultados: De acuerdo con los resultados, la morfometría geométrica resultó útil para demostrar diferencias en forma de la concha entre localidades; por ejemplo, se detectarondiferencias evidentes entre localidades de alta y baja altitud. Se determinó que la variación en la coloración de esta especie es independiente de factores a gran escala, dado que los especímenes examinados proceden de ambientes con condiciones similares. Por otro lado, la escultura de la protoconcha y la anatomía de B. torallyi resultaron coincidentes con la de otras especies de este género recolectadas en Argentina. Conclusiones: Se concluyó que el análisis de morfometría geométrica de la forma de la concha fue un buen complemento a la descripción cualitativa tradicional de caracteres de concha.

Functional leaf traits of understory species: strategies to different disturbance severities / Traços funcionais foliares de espécies de sub-bosque: estratégias às diferentes intensidades de perturbação

The specific leaf area (SLA) has been related to environmental disturbances, showing a positive correlation between the disturbances intensities and SLA in a plant community. These studies, however, assessed the responses of plant community as a whole, neglecting species attributes, such as the position in the vertical stratum of forests. Considering the importance of SLA to understand forest ecological processes, this study aimed to determine the influence of the disturbance regime on the SLA of understory species, considering that, unlike for communities as a whole, an increase in the disturbance intensity implies a decrease in SLA of understory species. This study was conducted in nine understories of seasonal forests in Brazil. The most abundant species were selected and their SLA were evaluated. The variability of SLA among populations in different forests was analyzed by Student’s t-tests. The SLA of the understories (SLAU) was also compared by an adaptation of the Community-weighted mean index. The comparison of species SLA showed significant differences among the populations of understories under different disturbance regime, showing a decrease in SLA with an increase in the disturbance intensity. Similar results were found for the SLA of understories communities (SLAU), corroborating our hypothesis. The correlation between a reduction in species SLA and in SLA of understory with an increase in disturbance intensity, contradicted the trend observed in the literature for the community as a whole. This study highlights the importance of the evaluation of SLA in understories, as an indicator of the successional stage of communities.

A área foliar específica (SLA) tem sido relacionada a distúrbios ambientais, apresentando uma correlação positiva entre a intensidade de perturbação e a SLA da comunidade vegetal. Estes estudos, no entanto, avaliaram as respostas da comunidade vegetal como um todo, negligenciando os atributos por espécies, tais como a posição vertical no estrato florestal. Considerando a importância da SLA para entender os processos ecológicos das florestas, este estudo teve como objetivo determinar a influência do regime de perturbação na SLA de espécies de sub-bosque, cuja hipótese é que, ao contrário de comunidades como um todo, um aumento na intensidade de perturbação implica na diminuição da SLA de espécies de sub-bosque. Este estudo foi realizado em nove sub-bosque de florestas estacionais no Brasil. As espécies mais abundantes foram selecionados e suas SLA foram avaliadas. A variabilidade de SLA entre as populações em diferentes florestas foi analisada pelo teste t de Student. O SLA dos sub-bosque (SLAu) também foi comparado por uma adaptação do índice de média ponderada da comunidade. A comparação de SLA das espécies mostraram diferenças significativas entre as populações de sub-bosque sob um regime de distúrbios diferentes, mostrando um decréscimo na SLA com um aumento na intensidade de perturbação. Resultados semelhantes foram encontrados para o SLA dos sub-bosque (SLAu), corroborando nossa hipótese. A correlação entre a redução no SLA espécies e SLA do sub-bosque com um aumento na intensidade de perturbação contradiz a tendência observada na literatura para a comunidade como um todo. Este estudo destaca a importância da avaliação de SLA em sub-bosque, como um indicador do estágio sucessional das comunidades.

The use and limits of ITS data in the analysis of intraspecific variation in Passiflora L. (Passifloraceae)

The discovery and characterization of informative intraspecific genetic markers is fundamental for evolutionary and conservation genetics studies. Here, we used nuclear ribosomal ITS sequences to access intraspecific genetic diversity in 23 species of the genus Passiflora L. Some degree of variation was detected in 21 of these. The Passiflora and Decaloba (DC.) Rchb. subgenera showed significant differences in the sizes of the two ITS regions and in GC content, which can be related to reproductive characteristics of species in these subgenera. Furthermore, clear geographical patterns in the spatial distribution of sequence types were identified in six species. The results indicate that ITS may be a useful tool for the evaluation of intraspecific genetic variation in Passiflora.