Concealed Surfaces Research Articles

Forty years later: a new Andean stream treefrog of the genus Hyloscirtus (Anura: Hylidae) from Ecuador, with comments on arm hypertrophy in the H. larinopygion group

We present the description of a novel treefrog species inhabiting the Andean streams in southeastern Ecuador that has been erroneously identified as Hyloscirtus lindae for four decades. The new species is closely related to H. tapichalaca and is part of the southern clade of the H. larinopygion group, which comprises five species confined to the southeastern Andes of Ecuador to the northeastern Andes of Peru. It is diagnosed from its close relatives by a unique combination of characteristics, including hypertrophied forelimbs in males, a pronounced, curved, and protruding spine-shaped prepollex, a substantial supracloacal flap, supratympanic fold, digital discs colored in shades of orange-red or bright-red, and the concealed surfaces of limbs displaying a bluish-gray hue and dorsal spicules in males. We briefly explore the implications of this discovery for the evolution of arm morphology in the H. larinopygion group. Our findings underscore the continued importance of periodically reviewing historical specimens, leading to unexpected discoveries; once again confirming the importance of natural history museums and their custodian biological collections.

A study of the dynamic damage characteristics of Rock-Like materials with different connectivity of concealed structural surfaces

In order to explore the dynamic mechanical properties and failure laws of rock masses with different connectivity of concealed structural surfaces, this study used rock-like materials to produce specimens with concealed structural surfaces at different connectivity levels. An improved Separated Hopkinson Pressure Bar (SHPB) experimental system was applied in combination with the finite element software ANSYS/LS-DYNA. Then, the dynamic properties, energy transfer laws, and failure characteristics of the concealed structures with different connectivity were analyzed. The research results showed that the peak stress and yield stress level of the specimen gradually decreasedas connectivity parameter increases. However, it was observed that the average strain rate continued to increase with the increased connectivity of the structural surface under the same impact velocity. The stress–strain curve of the specimen with a concealed structure appeared as “stress bimodality.” This phenomenon was determined to be related to the structural surface connectivity and impact velocity of the specimen. In addition, the specimen’s energy absorption rate first increased and then decreased with the increases in the structural surface connectivity. It was found that the reflection coefficient gradually increased, and the transmission coefficient exhibited a negative linear relationship with the connectivity of the structural surface. In addition to tensile cracks, vertical arc-shaped shear cracks also appeared in the failure mode of specimens with concealed structural surfaces. Moreover, the order of the appearance of the tensile cracks and compression-shear cracks, as well as the sizes of the cracks, were determined to be closely related to the structural surface connectivity. This study’s research results also revealed the deformation and failure laws and energy evolution characteristics of the rock-like materials with different concealed structural surface connectivity under different velocity impact loads.

A Practical Assessment of the Disinfectant Efficacy of UV Light with and without Ozone Using a Novel Transfer Hatch in a Research Animal Facility.

Most in vivo animal research and breeding using mice and rats in China takes place in facilities under barrier conditions. Items being moved across the barrier are typically disinfected using UV radiation in a transfer hatch. However, the time periods necessary for this disinfection technique are inefficient, and disinfection is frequently incomplete, especially if concealed surfaces are present. The current study used a newly developed transfer hatch incorporating both UV and ozone disinfection to examine disinfection efficacy against 4 bacteria species (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii). Disinfection trials used UV and ozone, applied separately and in combination, for up to 30 min. Separate and combined treatments were also tested with a UV barrier. We found that if UV radiation has direct contact with surfaces, it is an efficient disinfection method. However, where surfaces are concealed by a UV barrier, UV radiation performs relatively poorly. The results of this study indicate that a combination of UV and ozone produces the most effective disinfection and is markedly quicker than current disinfection times for UV applied on its own. This novel transfer hatch design therefore allows more complete and efficient disinfection, improves workflow, and reduces barrier breaches by pathogens that may affect animal health and welfare and compromise research outcomes.

A new species of Pristimantis (Anura: Strabomantidae) with a colourful venter from the cloud forests of Colombian western Andes.

The Terrarana frogs of the genus Pristimantis are acknowledged for their direct development into froglets and for their astonishing species richness, which renders it the anuran genus with the highest number of species. We describe a new species of Pristimantis from the northwestern Andes of Colombia. The species is distributed from an area between 2750-2900 m.a.s.l. in the Mesenia-Paramillo Nature Reserve. Pristimantis postducheminorum sp. nov. differs from other, phylogenetically related, or similar resembling Pristimantis taxa by a striking yellow coloration in the ventral area, dark grey coloration in the concealed surfaces of the thighs and groin, absence of nuptial pads, presence of lateral fringes on fingers, presence of vomerine odontophores triangular in shape from the ventral view, and absence of dorsolateral folds. Molecular phylogenetics place this new species close to P. satagius and therefore within the P. ridens species group. The new species is also phylogenetically close and sympatric with the recently described P. ferwerdai, which further indicates that the Pristimantis fauna has been notoriously underestimated in the Colombian western cloud forests, a fact that should be considered in assessments of environmental impact.

Our unknown neighbor: A new species of rain frog of the genus Pristimantis (Amphibia: Anura: Strabomantidae) from the city of Loja, southern Ecuador.

We describe a new species of rain frog of the genus Pristimantis from the city of Loja, Southern Ecuador, based on an integrative taxonomy approach, combining molecular, morphological and bioacoustics data. Pristimantis lojanus sp. nov. is a medium sized species of the phylogenetically strongly supported P. phoxocephalus group, and its sister species is P. torresi. The new species can be easily distinguished from its closest congeners and morphologically similar species (that also have acuminate snout with a fleshy keel) by its characteristic advertisement call and morphological features (dorsum finely tuberculate with scattered larger tubercles, flanks without longitudinal lateral folds, no markings in axilla, groin or on concealed limb surfaces, and bronze iris). Additionally, we describe the advertisement call of its sister species, P. torresi. Finally, we detail the current situation of the amphibian species present in the city of Loja and its surroundings.

A new species of Leucostethus (Anura, Dendrobatidae) from Gorgona Island, Colombia.

We describe a new species of Leucostethus from Gorgona Island, a small (13 km2) island located 35 km from the Pacific coast of southern Colombia. The new species most resembles L.argyrogaster and L.fugax from western Amazonia at 340–870 m elev. in Peru and Ecuador, with which it shares pale ventral coloration and orange suffusion of the axilla, groin and concealed surfaces of the hind limb, but it is most closely related to L.bilsa from ca. 340 km SW in the southern Chocó at 420–515 m elev., northwestern Ecuador. We report miniscule white spots on the posteroventral surface of the thighs of the new species and, on the basis of our preliminary assessment of their taxonomic distribution, hypothesize that their presence is a synapomorphy of Dendrobatoidea with subsequent losses in a few groups. Given the apparent restriction of the new species to Gorgona Island, it is Vulnerable according to IUCN Red List criteria. In addition to naming the new species, we also propose the following new combinations: L.alacris (Rivero and Granados-Díaz, 1990) comb. nov., L.dysprosium (Rivero and Serna, 2000) comb. nov., and L.yaguara (Rivero and Serna, 1991) comb. nov.

Genetic delimitation of Pristimantisorestes (Lynch, 1979) and P.saturninoi Brito et al., 2017 and description of two new terrestrial frogs from the Pristimantisorestes species group (Anura, Strabomantidae).

In the genus Pristimantis, species are often combined into taxonomic units called species groups. The taxonomy of these groups is frequently inaccurate due to the absence of genetic data from type series and repeated misidentifications generated by high morphological resemblance between taxa. Here, we focus on the P.orestes species group, providing the first genetic assessment of P.orestes sensu stricto from individuals collected from the type locality, with a reviewed diagnosis and description of advertisement calls. We find that two lineages previously named P.orestes are genetically distinct and should be separated into two different species. Based on genetic and morphological data, we name one of these species P.cajanumasp. nov. This new species is morphologically distinct from other members of the group by having shagreen dorsal skin, evident dorsolateral folds, broader discs on toes and fingers and pale gray ventral coloration. Additionally, P.saturninoi is placed within the P.orestes species group based on genetic data from its type series. However, we find that one of its paratypes is genetically distinct and belongs to a clade containing a new species we name P.quintanaisp. nov. This new species is morphologically distinguished by lacking a tympanic membrane and vocal sacs in males, and by having expanded discs on toes and fingers, finely tuberculated dorsal skin and irregular white or cream spots in the groin and concealed surfaces of thighs. Our findings highlight the importance of providing genetic characterization and placement from the type series in taxonomic challenging groups, such as Pristimantis. We also suggest that the diversity of species within the P.orestes group will increase as more sampling is achieved in the southern Andes of Ecuador.

(Invited) Fundamentals and Applications of Directional and Isotropic Atomic Layer Etching

Atomic Layer Etching (ALE) is a cyclic process comprised of a self-limited surface modification step followed by a self-limited step to remove the modified layer. Based on this definition, there are several approaches to realize and classify ALE. For instance, one can distinguish between directional and isotropic ALE depending on whether the removal of the activated layer is accomplished by ion bombardment or thermal energy. Thanks to such salient performance benefits as uniformity across all length scales and selectivity, atomic layer etching is being proliferated in production. Directional ALE was the first process to go into production because most critical etch applications require directionality. Isotropic ALE is an emerging branch based on chemical reactions akin to those uses in thermal ALD. The term “isotropic” means that the etch proceeds in all directions. This property is particularly valued in vertical device integration where materials need to be removed from vertical and concealed surfaces. In this talk, a conceptual framework for directional and isotropic ALE will be introduced to explain the performance benefits and limitations of both technologies. Experimental and theoretical results as well as applications examples will be presented to illustrate the concepts.

Remedial boron treatment of difficult to access timber in buildings

The quest to understand remedial treatment for timber framing began following the ‘leaky building crisis’ in New Zealand which came to prominence in late 1990s. Several in situ remedial treatment products are used in New Zealand. However, effectiveness of these treatments is still unclear, particularly in situations where not all faces of the timber can be accessed. This research was conducted to establish whether a ‘double coat brush-on’ or ‘double coat brush-on plus injection treatment between studs’ system would give the most surface coverage and retention of a commonly used remedial treatment chemical, boron. Results showed that in the ‘double coat brush-on’ process, the concealed surfaces were left largely untreated resulting in variable preservative retention between components and relatively low overall preservative retention in the multiple stud units. However, the ‘brush-on plus injection treatment’ application gave much better preservative spread onto concealed surfaces of both vertical and horizontal members. Most samples tested achieved average cross-section boron retention levels of 0.4 % BAE m/m (NZS 3640, H1.2 treatment specification), although the treatment was concentrated in the outer 30 % of the timber, hence not achieving the required full sapwood penetration. Because of the variability associated with the boron injection process, it is recommended that this remediation method should only be used where there is a high degree of confidence that there is no decay present between studs or lintel members. All attempts should be made to remove any decaying timber while repairing leaky buildings.

Cryptic diversity in the Hypsiboas semilineatus species group (Amphibia, Anura) with the description of a new species from the eastern Guiana Shield.

We used molecular and morphological data to investigate the hidden diversity within the Hypsiboas semilineatus species group, and more specifically within H. geographicus, an allegedly widespread species in northern South America. As a result, the identity of H. geographicus was clarified, several candidate species were detected and one of them, from the eastern Guiana Shield, is described herein as a preliminary step to resolve the taxonomy of the group. Hypsiboas diabolicus sp. nov. is mainly distinguished from closely-related species by an acuminate snout in lateral view, well-developed webbing between fingers and toes, and unspotted carmine/crimson colouration on the concealed surfaces of legs, feet and hands in life. The tadpole of the new species is described and is characterized by a large A-2 gap, a mostly single row of large marginal papillae, and a dark brown to black colouration. We also describe the advertisement call of the new species, which is defined as a soft call consisting of short clusters of 2-3 chuckles with a dominant frequency ranging between 1.11-1.19 kHz. Hypsiboas diabolicus sp. nov. is currently known only from the eastern Guiana Shield, and is probably endemic to that region. The new species' range overlaps broadly with another candidate species referred to as H. aff. semilineatus 1. Our preliminary results stress out a high cryptic diversity in that species group and the need for a formal redescription of Hypsiboas geographicus based on more topotypic material than what is currently available to properly sort out the taxonomic status of several lineages in that clade.

A new small golden frog of the genus Pristimantis (Anura: Craugastoridae) from an Andean cloud forest of Colombia

A new species ofPristimantisis described from an Andean cloud forest at 2650 m in the Cordillera Oriental of Colombia.Pristimantis doradosp. nov. is similar to and could be closely related toP. acutirostris, but can be readily distinguished from this latter species by the absence of a tympanic annulus, vocal slits, vocal sac and reticulations on concealed surfaces, and by having a metallic gold iris with a brown horizontal streak. The phylogenetic position of the new species is recovered and we provide its advertisement call, which this species manages to emit despite lacking a vocal sac and vocal slits. This discovery reminds us that despite the extensive research on the alpha-taxonomy ofPristimantisin Colombia, fieldwork in high montane forests continues to yield previously unknown species.

Individual‐based analyses reveal limited functional overlap in a coral reef fish community

Detailed knowledge of a species' functional niche is crucial for the study of ecological communities and processes. The extent of niche overlap, functional redundancy and functional complementarity is of particular importance if we are to understand ecosystem processes and their vulnerability to disturbances. Coral reefs are among the most threatened marine systems, and anthropogenic activity is changing the functional composition of reefs. The loss of herbivorous fishes is particularly concerning as the removal of algae is crucial for the growth and survival of corals. Yet, the foraging patterns of the various herbivorous fish species are poorly understood. Using a multidimensional framework, we present novel individual-based analyses of species' realized functional niches, which we apply to a herbivorous coral reef fish community. In calculating niche volumes for 21 species, based on their microhabitat utilization patterns during foraging, and computing functional overlaps, we provide a measurement of functional redundancy or complementarity. Complementarity is the inverse of redundancy and is defined as less than 50% overlap in niche volumes. The analyses reveal extensive complementarity with an average functional overlap of just 15.2%. Furthermore, the analyses divide herbivorous reef fishes into two broad groups. The first group (predominantly surgeonfishes and parrotfishes) comprises species feeding on exposed surfaces and predominantly open reef matrix or sandy substrata, resulting in small niche volumes and extensive complementarity. In contrast, the second group consists of species (predominantly rabbitfishes) that feed over a wider range of microhabitats, penetrating the reef matrix to exploit concealed surfaces of various substratum types. These species show high variation among individuals, leading to large niche volumes, more overlap and less complementarity. These results may have crucial consequences for our understanding of herbivorous processes on coral reefs, as algal removal appears to depend strongly on species-specific microhabitat utilization patterns of herbivores. Furthermore, the results emphasize the capacity of the individual-based analyses to reveal variation in the functional niches of species, even in high-diversity systems such as coral reefs, demonstrating its potential applicability to other high-diversity ecosystems.

Wall lizards display conspicuous signals to conspecifics and reduce detection by avian predators.

Visual signals are often under conflicting selection to be hidden from predators while being conspicuous to mates and rivals. Here, we investigated whether 3 different island populations of Aegean wall lizards (Podarcis erhardii) with variable coloration among diverse island habitats exhibit simultaneous camouflage and sexual signals. We examined whether signals appear better tuned to conspecific vision as opposed to that of avian predators, and whether background-matching camouflage and sexual signals are partitioned to specific body regions. This could facilitate both covert sexual signaling and camouflage according to the viewing perspectives of predators and conspecifics. We found that lizards typically appeared twice as conspicuous to conspecifics than to avian predators against the same visual background, largely due to lizards’ enhanced sensitivity to ultraviolet, suggesting that P. erhardii signals are tuned to conspecific vision to reduce detection by predators. Males were more conspicuous than females to both predators and conspecifics. In 2 populations, male backs were relatively more camouflaged to predators compared to signaling flanks, whereas in females, exposed and concealed surfaces were camouflaged to predators and generally did not differ in background matching. These findings indicate that lizard coloration evolves under the competing demands of natural and sexual selection to promote signals that are visible to conspecifics while being less perceptible to avian predators. They also elucidate how interactions between natural and sexual selection influence signal detectability and partitioning to different body regions, highlighting the importance of considering receiver vision, viewing perspectives, and signaling environments in studies of signal evolution.

Carbonate production and deposition in a warm-temperate macroalgal environment, Investigator Strait, South Australia

The prolific macroalgal forests in shallow (< 20 m), warm-temperate, marine environments off southern Yorke Peninsula, South Australia have two carbonate-producing habitats, 1) upward-facing, exposed rock surfaces beneath large phaeophytes, and 2) concealed rock surfaces under overhangs, on rock walls, in crevasses, and indentations that all lie behind a curtain of brown macroalgae. Exposed surfaces have three growth tiers; 1) a basal, cm-high veneer or turf of crustose corallines, geniculate corallines, and short fleshy red algae that are grazed by herbivorous gastropods, 2) an intermediate, 5–20 cm-high community of fleshy red algae, and 3) a 20–100 cm+-high canopy of large phaeophytes (especially Ecklonia, Cystophora and Xiophora) whose blades are locally encrusted with bryozoans, such as Membranipora membranacea, and spirorbids. Concealed surfaces of subvertical rock walls and cryptic habitats behind the macroalgal curtain have two tiers; 1) a cornucopia of encrusting plants and animals, especially crustose and geniculate corallines in shallow water, that give way in water depths > 4 m to numerous bryozoans (especially fenestrates), serpulid worms, numerous and diverse demosponges, ascidians, small solitary corals, epifaunal echinoids, and gastropods, and 2) a veil of macroalgae (mainly Cystophora and Ecklonia) that drapes down and shades the rock walls. Most carbonate sediment production does not come from calcareous epiphytes on the macroalgae but comes from the coralline algae and calcareous invertebrates living on the rock walls and in concealed depressions. Mollusks (gastropods and bivalves) and geniculate coralline algae with numerous lithoclasts, crustose coralline fragments, barnacle plates, serpulid worms, bryozoans, and large benthic foraminifers (especially Amphistegina) dominate the resultant gravels and sands; but there is little or no mud. This is because carbonate sediment is the result of production not only in the macrophyte factory but also in adjacent seagrass factories. Particles produced in the macroalgal factory are shed onto the adjacent seafloor, where they form the requisite sandy substrates for quick colonization by seagrasses. Thus, over time the sediment in this shallow but hydrodynaically energetic environment becomes a mixture of materials from the two sources with seagrasses contributing gastropods, large benthic foraminifers, spirorbids, bryozoans and articulated corallines to the sediment milieu. If this system is a typical example, then warm-temperate Neogene carbonate facies related to macroalgal factories should be a mixture of materials from the rocky substrates, a calcareous infauna, and marine seagrasses.

A new species of Pristimantis (Anura: Strabomantidae) from the Amazonian lowlands of northern Peru (Region Loreto and San Martín)

A new species of Pristimantis from the Amazonian lowlands of northern Peru (Regions of Loreto and San Martín) is described. The new species has a snout-vent length of 32.6–36.5 mm (n = 3) in adult females, and 20.0–25.1 mm (n = 4) in adult males. It differs from all Pristimantis of the Amazonian lowlands in having a contrasting life coloration pattern of black with white or whitish blue blotches in axilla, groin, anterior and posterior surfaces of the thighs and concealed surfaces of the tibia.

A New Species of Phasmahyla Cruz, 1990 (Anura: Hylidae) from the State of Bahia, Brazil

Abstract A new species of the genus Phasmahyla is described from an Atlantic Rain Forest remnant at Serra do Timbo, Municipality of Amargosa, State of Bahia, Brazil. The new species is recognized by its medium size for the genus (snout-vent length 32.4 to 35.8 mm in males); reduced to absent coloration with purple spots on concealed surfaces of arm, forearm, thigh, tibia, tarsus, and digits; male with moderate nuptial pad of minuscule horny asperities on finger I; tympanum distinct only on ventral half; dorsolateral glands well developed; dorsal skin slightly coarse; larval oral disc with distinct anterior and two posterior series of horny teeth; interrupted first posterior series of horny teeth slightly larger than the anterior one. Temporal and spectral parameters of the advertisement call are described for the new species, and for the first time for the genus Phasmahyla.

A new species of Phasmahyla Cruz, 1990 (Anura: Hylidae) from the Atlantic Rain Forest of the States of Minas Gerais and Bahia, Brazil

AbstractA new species of the genus Phasmahyla is described from Atlantic Rain Forest fragments at the Fazenda Duas Barras, Municipality of Santa Maria do Salto, northeastern State of Minas Gerais, at the Reserva Particular do Patrimônio Natural (RPPN) Serra do Teimoso, Municipality of Jussari, and at the Fazenda Santa Cruz, Municipality of Arataca, southern State of Bahia, Brazil. The new species is recognized by its medium size for the genus (SVL 33.3 to 38.0 mm in males, 42.8 to 48.6 mm in females); purple drops on flanks and concealed surfaces of forearm, thigh, and digits; male with moderate nuptial pad of minuscule horny asperities on finger I; tympanum distinct only on ventral half; supratympanic fold weakly developed and visible only behind the tympanum; loreal region slightly obtuse; larval oral disc with distinct upper and second lower series of horny teeth; and second lower series of horny teeth slightly shorter than the upper one.

A new species of the Pristimantis orestes Group (Anura: Leptodactylidae) from the Cordillera Occidental in northern Peru

We describe a new species of the Pristimantis orestes Group from cloud forest at 1700–1800 m in the Cordillera Occidental in northern Peru (Departamento de Cajamarca). The type series comprises one adult female and three males. The new species has a maximum snout vent-length of 29.4 mm, a long snout, dentigerous processes of vomers present, discs on outer fingers broadly expanded, males that have vocal slits present and nuptial pads absent, and a distinct color pattern consisting of tan blotches and spots on a brown venter, anterior and posterior surfaces of the thighs, concealed surfaces of the shanks, and axilla and groin, dark brown with tan blotches and spots. The Pristimantis orestes Group contains 12 species, of which nine occur in the Cordillera Occidental in northern Peru. Nuptial pads as diagnostic characters in Pristimantis are briefly discussed.

A new, toxic species of Colostethus (Anura: Dendrobatidae: Colostethinae) from the Cordillera Central of Colombia

A new species of Colostethus is described from cloud forest in the Cordillera Central of Colombia at approximately 2100–2500 m above sea level. It is a riparian species not known to occur more than a few meters from the water’s edge. Specimens were collected in grassy vegetation and on and beneath rocks along streams and pools, in both primary forest and in or at the edge of forest clearings. Most specimens were collected during the day, but several were observed to be active at night. The new species differs from other species of Colostethus in lacking pale oblique lateral and ventrolateral stripes, possessing a pale dorsolateral stripe, lacking or having at most rudimentary toe webbing, and possessing a marbled or reticulated ventral color pattern. Adult males of the new species possess a swollen third finger and a gray or black throat. In life, the new species possesses bright lemonor golden-yellow flash marks on the axilla, groin, belly, and concealed surfaces of the thigh and shank, and bluish-white ventral coloration, and it exudes a milky secretion from the skin. The aqueous extract of the skin is toxic, but additional samples are required to determine the nature of the toxic compound(s).

A new species of Phyllomedusa (Anura: Hylidae: Phyllomedusinae) from northwestern Venezuela

A new species of the Phyllomedusa tarsius group (Anura: Hylidae: Phyllomedusinae) from northwestern Venezuela can be differentiated from other species in the group by its small size, white and pink bars on the concealed surfaces of legs, and distinctive mating call; it is known only from xeric areas in the vicinity of Serranía de San Luis, Estado Falcón, Venezuela. The call is described, and some natural history data is also provided. The Phyllomedusa tarsius group includes five species and is defined by morphological characters (with one putative synapomorphy).