The invasive land flatworm Obama nungara (Platyhelminthes: Geoplanidae) reaches a natural environment in the oceanic island of São Miguel (Açores)

During an entomological sampling trip in the island of São Miguel (Açores, Portugal) on 02-11-2019 by José Rafael González-López, one specimen of the invasive flatworm Obama nungara Carbayo et al. 2016 was found under a rock (Fig. 1A). The specimen was photographed in situ and identified by its external morphology based on its large and broad leaf-like body with nearly parallel body margins, narrow and rounded anterior end, rounded posterior end, and dorsal pigmentation consisting of a light brown ground color covered with dark longitudinal and irregular stripes, and ventral surface grayish-white. Recent studies (Justine et al. 2020; Negrete et al. 2020) showed the reliability of photograph-based identification of O. nungara specimens. It is the sixth island where this species has been found (after Guernsey, Great Britain, Ireland, Corsica, and Madeira).

Two new species of burrowing crayfish in the genus Lacunicambarus (Decapoda: Cambaridae) from Alabama and Mississippi

While sampling for the Rusty Gravedigger, Lacunicambarus miltus, Taylor et al. (2011) found one or more potentially undescribed burrowing crayfish species in the genus Lacunicambarus inhabiting the area between the Pascagoula River and Mobile Bay in southern Alabama and Mississippi. Molecular analyses by Glon et al. (2018) confirmed that samples from this area were genetically distinct from other Lacunicambarus crayfishes. These findings prompted a dedicated sampling trip in January 2020. We used morphological and molecular analyses to investigate the specimens we collected and, based on our results, we describe two new crayfish species: the Lonesome Gravedigger, L. mobilensis sp. nov. and the Banded Mudbug, L. freudensteini sp. nov. Lacunicambarus mobilensis sp. nov. is sister to the Rusty Gravedigger, L. miltus, while L. freudensteini sp. nov. is sister to the Painted Devil Crayfish, L. ludovicianus. Both new species are currently known from a small number of sites in southern Alabama and Mississippi and may require conservation attention. In addition, we provide an updated key to Lacunicambarus crayfishes that includes these new species.

Do different sampling designs produce differences in the metrics of curimba, Prochilodus lineatus (Characiformes: Prochilodontidae)?

ABSTRACT Probabilistic sampling, a classical recommendation for unbiased data, has been often overlooked. Fish sampling in reservoirs, unlike most rivers, can be accomplished by a variety of probabilistic sampling designs due to few restrictions in the choice of sampling sites (SSs). We evaluated whether population metrics of Prochilodus lineatus differ between fixed SSs (do not change with each sampling trip) and variable SSs (change with each sampling trip) in the Volta Grande (VGR) and Jaguara (JR) reservoirs of the Grande River, Paraná River basin, Brazil. We used gillnets to sample fish at nine probabilistic fixed SSs and nine probabilistic variable SSs per sampling trip. We conducted 25 sampling trips in VGR and 22 in JR during 2011 to 2015, and performed 35 analyses of 8 metrics for each reservoir. We found sampling design influenced only 7% of the analyses involving three metrics, apparently caused by biased data of fixed SSs. We attribute the small percentage of analyses influenced by sampling design to the low spatial heterogeneity of the reservoirs. The choice of the most appropriate sampling design seems to depend on the type of variation (temporal or spatial) that one wishes to detect, and the availability of time and financial resources.

Habitat-specific distributions of some fishes in a tropical estuary

The species richness of fishes and the distributions of six fish species were compared among four habitat types, snaggy banks, clear banks, mud banks and mid channels, in an estuary in tropical Australia. Both day and night samples were collected in fish traps, on four occasions, three months apart. On each sampling trip the highest number of species was trapped from snaggy habitats, intermediate numbers from clear banks or mud banks, and the fewest species from mid channels. Although more species occurred in night than in day samples, the pattern of difference among habitats was consistent. The probability of capture of the six most abundant species, Acanthopagrus australis, Acanthopagrus berda, Arothron manilensis, Arius argyropleuron, Epinephelus coioides and Lutjanus russelli, was compared among habitat types and between day and night samples. Overall, snag habitats tended to be associated with high probabilities of capture of a number of species, particularly A. berda and L. russelli. At night, mid channels were characterized by high numbers of A. argyropleuron. Clear and mud banks, and day samples from mid channels were associated with low numbers of most species.