A novel epidermal gland type in lizards (α-gland): structural organization, histochemistry, protein profile and phylogenetic origins

Chemical signalling is an essential component of the communication system of lizards, and epidermal glands are responsible for producing semiochemicals that regulate many behavioural interactions. Two types of epidermal glands have been previously described for lizards: follicular and generation glands. Generation glands are characterized by the aggregation of novel glandular cell types in the epithelium and the lack of a lumen or external pore. Despite the fact that several subtypes of generation glands have been recognized over the years, the morphology, taxonomic distribution, function and evolutionary origins of generation glands remain nearly unexplored in Neotropical clades. Here, we describe a novel escutcheon-type generation gland (‘α-gland’) for lizards of the South American family Tropiduridae, characterize its structural and ultrastructural organization, and study the homology of the constituent parts in a phylogenetic framework. The α-glands emerged in the ancestor of Eurolophosaurus, Plica, Strobilurus, Tropidurus and Uracentron, and are found in at least 39 species with diverse ecological habits. We preliminarily analysed the protein profile of α-glands and discovered differential expression of protein components between sexes. Our investigations change the general view about epidermal gland homology, leading us to argue that generation and follicular glands are possibly more closely related functionally and evolutionarily than previously thought.

Astacopsidrilus hibernicus sp. nov. (Phreodrilidae, Oligochaeta, Annelida) from Irish peatlands

The discovery of a large and flourishing population of Phreodrilidae in terrestrial peatlands in northwest Ireland was surprising on two counts: these oligochaete worms are usually aquatic and most of the species occur in the Southern Hemisphere. The phreodrilids were discovered in a project that targeted Enchytraeidae, therefore methods adapted to the investigation of enchytraeids could be applied, including the study of living animals and properly fixed whole mounts. DNA sequencing was also performed. All worms identified here belong to one species, new to science, and placed in the genus Astacopsidrilus, because of the ventral position of the spermathecal pores and the opening of the female funnels inside the spermathecal vestibule. Astacopsidrilus hibernicus sp. nov. is mainly distinguished by thick segmental cushions of epidermal gland cells on the dorsal side of the posterior body half. Male sexual organs and spermathecae are comparatively small and without the often-observed bizarre modifications common in species of this family. DNA sequencing yielded a fragment of the 16S rRNA gene. This is the first description of a phreodrilid species from Europe; the few previous recordings of this family in Ireland and the United Kingdom had been left unidentified.

Epidermal Gland Inspired Self-Repairing Slippery Lubricant-Infused Porous Coatings with Durable Low Ice Adhesion

The limited durability of slippery lubricant-infused porous surfaces (SLIPS) restricts their practical applications. Inspired by the epidermal glands of skins, we developed a facile approach to durable SLIPS with gland-like storage and release functions for icephobicity. By introducing a hybrid surfactant as a lubricant into the polydimethylsiloxane (PDMS) matrix, lubricant capsules were formed and mono-dispersed in the matrix, working as gland-like structures to release lubricant. The obtained SLIPS showed durable low ice adhesion strength and thermal durability simultaneously. In detail, the enhanced durability for icephobicity was demonstrated by 20 icing/deicing tests, in which the lubricant remains on the surface; the coatings showed negligible weight loss when stored at 100 °C for 60 h, displaying pronounced thermal durability of the slippery effect. Our current strategy sheds new light on a facile fabrication of mechanically and thermally durable SLIPS for icephobicity.

Evolution and role of the follicular epidermal gland system in non-ophidian squamates

Many lizard and amphisbaenian lineages possess follicular glands in the dermis of the inner thighs and/or the area anterior to the cloaca. These tubular glands produce a holocrine secretion that finds its way to the external world through pore-bearing scales (femoral and/or preanal pores). Secretions are composed of proteins and many lipophilic compounds that may function as chemosignals in lizard and amphisbaenian communication. In recent years, we have begun to develop an understanding of the adaptive significance of these secretions, and they are currently thought to play an important role in a variety of processes in these animals. While it appears that epidermal gland secretions function in intra- and interspecific recognition and territoriality, research has focused largely on their role in mate assessment. Despite these recent studies, our knowledge on the true role of the chemicals found in epidermal secretions remains poorly studied, and there are many possible avenues for future research on this topic. Here, we review the literature on the follicular epidermal glands of non-ophidian squamates and provide a first taxon-wide overview of their distribution.

Studies on specialized epidermal derivatives in iguanian lizards: II. New data on the scalation of the Malagasy iguanas of the genus Oplurus (Sauria: Iguanidae)

The details of the ventral scalation were examined in adult and young specimens of seven species of the Malagasy iguanids of the genera Chalarodon Peters, 1854 and Oplurus Cuvier, 1829, both visually and using light microscopy. For the first time, we report data on the topography, morphology and histology of epidermal glandular structures of the genus Oplurus. The modified swollen scales, callous-like in appearance, were described in the abdominal, pre-cloacal and femoral integument. Histological investigation confirmed a presence of the epidermal generation glands of the escutcheon type. In the lizards of the genus Oplurus the epidermal glands are mainly male characteristic, although partially modified ventral scales of the females suggest that they also have a potential capability to production of epidermal gland generation. A biological role of these scales is unclear, as well as their possible relations to lizard's ecology and behaviour.

Description of a new Fridericia species (Oligochaeta: Enchytraeidae) and its molecular comparison with two morphologically similar species by PCR-RFLP

A new species, Fridericia crassiductata sp.n. was described and compared by DNA fragment analyses (PCR-RFLP), with two similar species, Fridericia ratzeli (Eisen,1872) sensu Nielsen & Christensen (1959) and F. eiseni Dózsa-Farkas, 2005. The main characteristics of the new species are: 13–20 mm long, 0.5–0.7 mm wide, segment number: (38)–40–56, spermatheca with 9–10 large, sessile, globular diverticula, long and thick ectal duct, and two very large (80–130 µ m long) egg shaped ectal glands. Maximum ten chaetae per bundle, typical brown reticulate epidermal gland cells noticeable on the body surface. The oesophageal appendage is variable between type-a and type-c (according to Möller 1971) the branches are located proximally. The seminal vesicle is large, the penial slit is longitudinal with more transverse components. Three subneural glands in XIV–XVI. The new species was collected only in the Zemplén Mountains in Hungary, in similar biotopes (between and under the leaf-litter) to those of the common F. ratzeli. It may be hypothesized that it fills the ecological role of F. ratzeli because, although all three compared species occurred in this area, F. ratzeli was very seldom found and never together with the new species. The three species were also examined by molecular methods. Which confirmed the existence of three distinct species. Both morphological and molecular studies indicate that F. ratzeli is still not a homogeneous species. It seems that the applied molecular methods help distinguish morphologically very similar species.