Acta Zoologica最新文献

The palaeofauna of the Quaternary is mostly known from the mammals' record, while the herpetofauna is less represented. In the same way, in northeastern Argentina reptile fossils records are scarce, usually represented by preliminary communications. This paper focuses on the study of herpetofauna remains from the Isla El Disparito archaeological site. The faunal materials collected at the site revealed an increase in taxonomic diversity related to the Quaternary herpetofauna in the IED site, with over 50% of the bone remains represented by anurans and at least six recognized squamates taxa. The purpose of this study is to properly identify these new records of herpetofauna remains from northeastern Argentina during the Holocene as well as to provide a dichotomous key of postcranial remains for identifying extant squamates taxa in other Quaternary sites from Argentina. The identified squamate assemblage includes the lizard Ophiodes sp., the snake families Typhlopidae, Dipsadidae, Viperidae and undetermined colubroids, along with anuran bone remains (Anura indet. and ?Hylidae). Additionally, the findings contribute to a better understanding of the herpetological assemblage in Argentina, providing insights into the composition of South American squamates during the Quaternary.

The fat body, originating from mesodermal tissue of coelomic cavities during embryogenesis, can be found throughout the insect's body. In some insects, the fat body has two types (peripheral and perivisceral fat bodies) according to its location. In the fat body, trophocytes are known to be the basic cell type. Other fat body cells differentiating from the trophocytes are urocytes, mycetocytes, chromatocytes and haemoglobin cells. The study aimed to demonstrate the general structure and cell types of the fat body during the postembryonic developmental stages of Bombyx mori (L.). With Haematoxylin–Eosin staining, there is a single type of fat body throughout the larval stages but during Pp and P0 stages it consists of perivisceral and peripheral fat bodies. We also observed that the compact structure of the fat body at the beginning of the larval stage began to loosen as it transformed into the pupal stage. In the adult stage, it was reorganized during the metamorphosis and it didn't show both fat bodies distinction. At this stage, the fat body appeared in a loose, lace-like structure. We determined that B. mori fat body only consists of trophocytes and also among them; the fat body associated cells, oenocytes are detected.

Synalpheus ubatuba zoea I was described by assessing laboratory-hatched larvae. It was compared to other Synalpheus descriptions available in the literature. Partial sequences of parental female's 16S rRNA were analysed and it provided additional evidence for species identification. The first S. ubatuba zoea can be identified by a set of morphological characteristics, namely: antennal scale 4-articled; basial endite of the maxillule with 3 stout spines + 1 spine; coxal endite of the maxilla with 3 plumose setae and 1 simple seta; basis of the first maxilliped with 4 spines and 2 simple setae; endopod of the third maxilliped with 5-articled with 0, 0, 0, 2 (1 serrate + 1 simple) setae, 4 simple setae. There was significant larval morphology difference between these characteristics in comparison to other species in the Brevicarpus group (S. brevicarpus and S. minus) which S. ubatuba belongs to. Despite systematic and ecological information provided in the original S. ubatuba description, the present study is the first to focus on the particular features of this species' larval morphology. Evidence of the herein provided larval morphology traits in addition to potential comparison to congeners presenting well-known larval descriptions, supported the identification of newly discovered species.

Epidermal cell proliferation and differentiation during formation of the beak in tadpoles of Rana dalmatina. Acta Zoologica (Stockolm). The beak utilized in tadpoles of R. dalmatina for crushing vegetables is formed of cornified cell layers. A row of large wedge-like cells forms a central pile that produces the sharp corneous lamina of the beak. The labial and oral surfaces of the beaks also accumulate corneous material during proliferation and differentiation of keratinocytes from the epidermis to form a sheath around the central corneous cells. Corneocytes are shed during the growth of tadpoles. Electron microscopy reveals that keratin and mucus granules are main components of these keratinocytes. Electron-dense organelles of unknown composition and with inside lamellae are also present. Using immunohistochemistry after post-injection of 5BrdU, a marker of cell proliferation, the main timing of formation of the beak has been determined. After 2–5 h from injection, labelled nuclei of keratinocytes are seen in the basal layer, and sparse suprabasal labelled nuclei are detected after 5 h. Labelled keratinocytes are seen in suprabasal layers at 2 days post-injection. At 5 and 6 days labelled keratinocytes are present in central corneous cells and in the lateral shell of corneocytes forming the labial and oral beak sides. Shedding a complete stratum corneum likely takes more days, but this depends on feeding usage.

Ticks are blood-sucking parasite and transmit pathogens to humans, domestic and wild animals. Ticks are seriously damage the production of sheep and goats, resulting in heavy economic loss to farmers. The present study investigated microscopic and molecular identification of ticks and tick-borne anaplasmosis infesting sheep and goats in three agro-ecological zones of Pakistan. The collected ticks were identified at species level based on their morphological features through microscopy by using taxonomic keys. Four Rhipicephalus (R.) species namely: R. guilhoni Rh. geigyi, R. annulatus, R. pulchellus, two Haemaphysalis (Hae) spp. Hae. sulcate, Hae. punctate, one Ixodes ricinus and Hyalomma anatolicum were identified. The morphological variations in their body sizes, scutal pattern, female genital opening, spiracular plate length and male adanal plate were recorded. Furthermore, we assessed the effectiveness of utilizing the 16S rRNA gene sequence to differentiate Anaplasma samples at the species level. Microscopically suspected positive blood samples for Anaplasma were subjected to DNA extraction. Anaplasma was observed in the blood of 14 animals. The sequence similarity between Anaplasma marginale and the reference genome were 99.25%, while below this value indicating a distinct species. Phylogenetic analysis revealed close similarity with A. marginale isolates from Iran, Vietnam and Pakistan This study contributes to the epidemiology of ticks and TBPs in the KP province and highlights the importance of proactive TBP surveillance in livestock.

The evolutionary success of the Alpheus snapping shrimps is linked to their snapping claws, which were considered the key innovation in the evolution of these shrimps. However, many aspects of the evolution of snapping claws remain unknown. We evaluate the degree of intra- and interspecific variation in the shape of the snapping claw in different snapping shrimp Alpheus species. For this, we used a geometric morphometric tool. We investigated the variation in snapping claw shape from two perspectives — interspecific variation and sexual shape dimorphism — in three species: Alpheus angulosus, A. carlae, and A. estuariensis, from three locations along the southern coast of Bahia state in northeastern Brazil. Our results revealed interspecific variation in the shape of the snapping claw among A. angulosus, A. carlae, and A. estuariensis. In addition, sexual shape dimorphism was confirmed in A. angulosus and A. carlae. However, in A. estuariensis, our results reveal sexual monomorphism in the snapping claw. Our findings highlight the importance of considering both ecological context and phylogenetic relationships when analysing the morphology of the snapping claw in Alpheus snapping shrimps. We suggest further investigations to better understand the interspecific variation and sexual dimorphism in snapping claws and their implications for the evolutionary history of these shrimps.

This study aimed at analysing the population structure and reproductive aspects of Callinectes ornatus present in the bycatch of shrimp fisheries off Sergipe (northeastern Brazil), and at comparing the findings with other regions. Samples were obtained monthly from shrimp trawlers based in the Pirambu municipality (11°S–37°W) from May/2015 to May/2016. Each specimen of C. ornatus was separated, identified and weighed (TW, total weight, g). Carapace length (CL, mm) and width (CW, not including lateral spines, mm) were measured, and the sex and stage of morphological maturity were identified. A total of 403 females and 427 males of C. ornatus were found and analysed. The overall sex ratio did not differ from 1:1. Males were larger and heavier than females. Biometric relations (CL-CW and TW-CW) were different between sexes. The size at first morphological maturity (CW_m) was 38.20 mm for females and 44.00 mm for males. The reproductive and recruitment periods were continuous, with some peaks throughout the year. Despite C. ornatus being a frequent species in shrimp bycatch, its exploitation status is still unknown.

Vespid wasps use legs primarily for locomotion and in contexts such as grooming, handling of food and nest materials. Studies on leg form and function are relatively scarce. We analysed measurements of legs of 127 species of all genera of Polistinae, and of 18 species of other subfamilies, with the intent of investigating the occurrence and phylogenetic locations of morphometric patterns. Body-size variation across Polistinae was determinant as to the absolute dimensions of legs, but allometric effects are generally small when comparing proportional length differences between differently sized species. Quite differently, size-independent shape aspects are notably distinct as expressed by regression residuals and are clearly phylogenetically structured. Most distinctive are the very long mid and hind legs (and simultaneously exceedingly short forelegs) of Mischocyttarus species, and the comparatively shorter legs of some Epiponini. We found that forelegs have evolved with relative independence of the mid and hind legs, which is probably related to functions associated with the transport and manipulation of food and materials. Most examined solitary species showed mid and hindlegs shorter than most social polistines and vespines. Forefemur shape in some solitary species (euparagiines, masarines and some eumenines) may be functionally related to fossorial habits.

Body and limb size are associated with many aspects of the biology of animals. Geographic variation in morphological traits has often been investigated through ecogeographical rules. Bergmann's rule posits an inverse relationship between body size and temperature in homeotherms, while Allen's rule posits that endothermic animals inhabiting colder climates have relatively shorter protruding parts (e.g., limbs) in comparison to populations from warmer climates. However, the applicability and validity of these rules in poikilotherms are currently contentious. In this study, we aimed to test predictions of Bergmann's and Allen's rules in populations of the Neotropical frog Boana platanera. We analysed 142 adult male museum specimens from 17 localities along a mountain range in western Venezuela. We obtained six external morphological measurements and assessed the correlation of body size and limb size with temperature data for each locality. Our results were contrary to the expectations but consistent with previous studies. All this together indicates that exceptions to the Bergmann's and Allen's rules are frequent and idiosyncratic in anurans. We discuss alternative hypotheses that could explain geographic variation of body and limb size in future studies.