Hydrophobic-hydrophilic crown-like structure enables aquatic insects to reside effectively beneath the water surface

Various insects utilise hydrophobic biological surfaces to live on the surface of water, while other organisms possess hydrophilic properties that enable them to live within a water column. Dixidae larvae reside, without being submerged, just below the water surface. However, little is known about how these larvae live in such an ecological niche. Herein, we use larvae of Dixa longistyla (Diptera: Dixidae) as experimental specimens and reveal their characteristics. A complex crown-like structure on the abdomen consists of hydrophobic and hydrophilic elements. The combination of these contrasting features enables the larvae to maintain their position as well as to move unidirectionally. Their hydrophobic region leverages water surface tension to function as an adhesive disc. By using the resistance of water, the hydrophilic region serves as a rudder during locomotion.

On the definition, status of research, diversity and prospect of exploration of the Genus Garra (Cypriniformes: Cyprinidae) from Mizoram, Northeast India

The cyprinid genus Garra includes small to medium-sized, benthic fish species that are usually found in fast-flowing rivers and streams. Fish of this genus have a modified lower lip forming a mental adhesive disc and horizontally placed pectoral and pelvic fins with a flat ventral profile. The genus Garra is vast and wide with each species exhibiting various differences at the morphological and molecular level. Reports on the exploration and investigation of the genus in Mizoram are few and those that are reported need certain validation and clarifications. Re-collection and elaborated review of this genus are obligatory. Therefore, meticulous analysis of these freshwater fish using morphological as well as molecular methods is required to validate previous findings. Furthermore, the review paper will shed a light on the diagnosis of the fish, status of research, and research prospects in Mizoram.

Knowing when to stick: touch receptors found in the remora adhesive disc

Remoras are fishes that piggyback onto larger marine fauna via an adhesive disc to increase locomotor efficiency, likelihood of finding mates and access to prey. Attaching rapidly to a large, fast-moving host is no easy task, and while research to date has focused on how the disc supports adhesion, no attention has been paid to how or if remoras are able to sense attachment. We identified push-rod-like mechanoreceptor complexes embedded in the soft lip of the remora adhesive disc that are known in other organisms to respond to touch and shear forces. This is, to our knowledge, the first time such mechanoreceptor complexes are described in fishes as they were only known previously in monotremes. The presence of push-rod-like mechanoreceptor complexes suggests not only that fishes may be able to sense their environment in ways not heretofore described but that specialized tactile mechanoreceptor complexes may be a more basal vertebrate feature than previously thought.

A new genus and two new species of miniature clingfishes from temperate southern Australia (Teleostei, Gobiesocidae)

A new genus and two new species of miniature clingfishes are described based on specimens collected from dense stands of macroalgae in intertidal and shallow subtidal areas along the coast of southern Australia. The new genus, Barryichthys, is distinguished from other genera of the Gobiesocidae by unique features of the adhesive disc, including elongate papillae in adhesive disc regions A and B, the reduction and/or loss of several elements of the cephalic lateral line canals, the lower gill arch skeleton, and the neurocranium, and by having two distinct types of pectoral-fin rays. Barryichthyshutchinsi is described based on 19 specimens (12.4–18.7 mm SL) from Western Australia and South Australia. Barryichthysalgicola is described based on 22 specimens (9.0–21.0 mm SL) from Victoria, New South Wales and Tasmania. The new species are distinguished from each other by characters of body and head shape, vertebral counts, and aspects of live colour pattern. The new genus shares several characters in common with Parvicrepis, another genus of miniature gobiesocids from southern Australia that also inhabits macroalgae habitats. The many reductions and novel characters of Barryichthys are discussed within the context of miniaturisation.

A new genus and species of clingfish from the Rangitāhua Kermadec Islands of New Zealand (Teleostei, Gobiesocidae)

Flexorincus, new genus and species, is described from 15 specimens (14.0–27.2 mm SL) collected from shallow (0–9 meters) intertidal and sub-tidal waters of the Rangitāhua Kermadec Islands, New Zealand. The new taxon is distinguished from all other members of the Gobiesocidae by a combination of characters, including a heterodont dentition comprising both conical and distinct incisiviform teeth that are laterally compressed with a strongly recurved cusp, an oval-shaped opening between premaxillae, a double adhesive disc with a well-developed articulation between basipterygia and ventral postcleithra, and many reductions in the cephalic lateral line canal system. The new taxon is tentatively placed within the subfamily Diplocrepinae but shares a number of characteristics of the oral jaws and the adhesive disc skeleton with certain members of the Aspasminae and Diademichthyinae.

Intensitas dan Variasi Morfometrik Trichodina sp. pada Benih Ikan Gurami (Osphronemus gouramy Lacepede) Pendederan I yang Dijual di Pasar Ikan Purwonegoro Kabupaten Banjarnegara

Purwonegoro Fish Market, Banjarnegara district is the largest fish market in Central Java southern and western parts. This fish market serves as a center for buying and selling fish and fish seed traffic in a particular place to the location of the fish farmers. It will possibly spread a particular type of disease from one area to another. Trichodina sp. is found in the seed of gouramy fish hatchery center area with the pathogenicity level reached 80%. Trichodina sp. has a big role in the cultivation of gouramy production by reducing the physical condition of the fish so dangerous and cause death of gouramy in the seed phase. The results showed that as many as 150 gouramy fish fry were examined, 56 gouramy fish fry were infected Trichodina sp. All of Trichodina sp. are found as many as 573 individual from the gouramy seeds infected. Total intensity of Trichodina sp. from gouramy seeds amounted to 10.97 individual. The measurement results morphometric characters Trichodina sp. show the variation of morphometric with body diameter from 47.5 to 112.5 μm; denticle ring diameter from 22.5 to 47.5 μm; denticle diameter of 12.5 to 42.5 μm, adhesive disc diameter 37.5 to 65 μm; membrane width 2.5-7.5 μm and the number of denticle 13-28. Trichodina sp. allegedly found there are three types of T. heterodentata, T. nigra, and T. acuta.

A new species of Tripartiella (Ciliophora: Trichodinidae) from Aequidens tetramerus (Perciformes: Cichlidae) in north Brazil

A new species of Tripartiella is described from the gills of the wild saddle cichlid Aequidens tetramerus in north Brazil. Wet smears of skin and gills of examined fish were air-dried at room temperature and impregnated with Klein’s dry silver method for examination of the adhesive disc’s structures and denticles. Total prevalence of parasitism was 65%. This ciliate is characterized as a small-sized trichodinid, body diameter 37.03 ± 4.9 μm, adhesive disc 30.50 ± 2.71 μm, denticulate ring 13.28 ± 0.8 μm and 24 ± 2.0 denticles. Taxonomic and morphometric data for the new species are discussed.