Gill‐derived glands in species of Astyanax (Teleostei: Characidae)

The presence of a gill‐derived gland is herein reported for the first time in males of species of Astyanax and related genera; they are described through histological cuts and SEM. The gill‐derived glands described for the Characidae, when fully developed, present a similar structure in different species. The main external feature of gill‐derived glands is the fusion of anteriormost gill filaments on the ventral branch of first gill arch. This fusion is caused by squamous stratified epithelial tissue that covers adjacent filaments, forming a series of chambers. In the region where the gill‐derived gland develops, the secondary lamellae of the gill filaments are much reduced or completely atrophied being characterized by the presence of glandular cells forming nests.     

Clasper gland morphology and development in Potamotrygon magdalenae (Elasmobranchii: Potamotrygonidae)

Clasper gland morphology and development in Potamotrygon magdalenae and its relation with the acquisition of reproductive maturity is described in males of different developmental stages (embryos, neonates, juveniles, and reproductively active and resting adults). The glands are subcutaneous masses in the proximal base of each clasper. They are partially bilobate organs with a ventral groove that bears a row of papillae. Glands tend to be asymmetric, the left gland has a larger size, a trend that has been observed in other organs of elasmobranchs. Glands are formed by radially organized tubular secretory units lined with a simple columnar epithelium with basal nuclei and granular eosinophilic cytoplasm; vascularized loose connective tissue surrounds the gland units. The gland is covered by two layers of striated muscle tissue in circular and longitudinal arrangement. The clasper glands begin to develop in neonates and their secretory activity begins in juveniles. The active secretion of the clasper gland is observed in mature males, it includes glycoproteins and sulfated mucopolysaccharides. The size of the glands has a positive and direct relationship with body size, measured as disc width. Significant differences in clasper gland size were found between mature (active and resting) and immature (neonates and juveniles) males, suggesting that the acquisition of the sexual maturity involves the increase in the size of the gland due to a highly augmented secretory activity. Therefore, clasper glands are clearly associated with the reproductive activity of males and their secretion should have an endocrine control as other sexual secondary organs. J. Morphol. 278:369–379, 2017. © 2017 Wiley Periodicals, Inc.     

Two new genera and species of the subfamily Brosmophycinae (Bythitidae,Ophidiiformes) from Northern Australia

Two new bythitid genera and species of the subfamily Brosmophycinae are described from Northern Territory, Australia.Brosmolus longicaudus, described from a single male specimen, is unique in the tribe Brosmophycini in having the anal fin origin well anterior to the midpoint of the body and thin, transparent skin on the head and body.Beaglichthys macrophthalmus, described from a single female specimen, differs from all other genera in the subfamily by the following combination of characters: eight branchiostegal rays, eye diameter longer than snout length, cheek scaly, anal fin origin at midpoint of body, three developed rakers on the first gill arch, 12 caudal fin rays, and 14 precaudal vertebrae.     

Parabrosmolus novaeguineae,a new genus and species of the subfamily Brosmophycinae from Papua New Guinea (Bythitidae,Ophidiiformes)

Parabrosmolus novaeguineae, a new genus and species of the subfamily Brosmophycinae (family Bythitidae) is described, based on a single specimen from Papua New Guinea. The genus is unique in the tribe Brosmophycini in having six branchiostegal rays and ten precaudal vertebrae, and is also similarly distinguished from two brosmophycine genera,Melodichthys andBeaglichthys, tribal allocations of the two latter being uncertain.Parabrosmolus also differs from all other genera in the subfamily by the following combination of characters: head scaly, anal fin origin slightly before midpoint of body, eye diameter shorter than snout length, three developed rakers on first gill arch and 16 (14+2) caudal fin rays.     

The morphology of the club glands on the dorsal fin of mature male shannies, Lipophvys pholis (L.) (Blenniidae: Teleostei)

The pelvic, pectoral, anal and dorsal fins of mature male, female and immature male Lipophrys pholis (L.) were examined by light microscopy for the presence of club glands. All fins except the dorsal showed a highly stratified epidermis and a thick cuticle. Club glands were present on the dorsal fin of mature male fisH but only during the breeding season. The development and decline of the club glands corresponds to the period of gonadal build-up and spawnout. Each club gland comprises several thousand bundles ofcolumnar cells. The columnar cells surround acentral pore which opens to the outside through a layer of Malpighian cells. The substance produced by the gland includes mucopolysacchdride. The function of the secretion is unknown and is discussed in relation to studies on similar glands in several Mediterranean blenniids.     

高原特有条鳅鱼类两新种在广西的发现及其动物地理学意义

描述了采自广西都安县红水河水系的条鳅亚科鱼类2个新种：丽纹云南鳅yhnnanilus pulcherrimussp．nov．在侧线长度、鳞片分布、鳍条数目、尾型、吻须长度等方面与侧纹云南鳅yunnanilus pleurotaenia(Regan,1904)最为相似,但新种独特的斑纹和上下唇的长乳突可明显与之区别,二者在一些度量特征上也有区别。黄体高原鳅Triplophysa flavicorpus sp．nov．与同分布于西江水系的南丹高原鳅T．nandanensis Lan et al．较为相似,并以下列特征组合与高原鳅属所有已知种相区别：背鳍分枝鳍条10根、臀鳍分枝鳍条6～7根、体被细鳞、侧线完全、具6条宽横斑和1条沿侧线的细纵纹、尾鳍深分又、尾鳍基具1半圆形黑斑、尾鳍上下叶各具2条黑色横斑、腹鳍末端后伸超过肛门、腋部具发达的肉质鳍瓣、上唇中央完全中断等。云南鳅属和高原鳅属均是高原特有类群,前者仅分布于云南东中部地区,后者则集中分布于青藏高原。两个新种的分布地均远离这两个属的分布中心,而且呈间断分布。通过各自相近种谱系关系分析,推测这种特殊的分布格局是通过隔域分化形成的。     

Chelonian mental glands

A survey of 69 of the 74 currently recognized chelonian genera revealed that 21 genera in three families (Emydidae, Platysternidae and Testudinidae) possess paired integumentary glands or gland vestiges in the anterior throat skin. These glands are here termed mental glands; they are holocrine and may be classified morphologically as follows: Class I mental glands are large, complex, multilobed, have specialized ducts, and are found only in the genus Gopherus: Class II mental glands are small, simple sacklike invaginations containing secretory cells or keratinizing cells. The structure of Class II glands varies from distinctive and saccular to shallow keratinized invaginations having no glandular tissue; they are found only in the families Platysternidae and Emydidae. Mental glands occur in 17 of the 22 genera in the subfamily Batagurinae (sensu McDowell, 64); only 2 of 9 genera in the subfamily Emydinae have these glands. The taxonomic occurrence of mental glands suggests that they are primitive structures. The loss of mental glands in most emydines is interpreted as a subfamilial trend toward integumentary simplification.     

Hastatobythites arafurensis, a new bythitid genus and species from Australia (Bythitidae, Ophidiiformes)

A new genus and species of the subfamily Bythitinae (Bythitidae),Hastatobythites arafurensis, is described on the basis of two specimens from the Arafura Sea. The genus is unique in the subfamily in having two anteriorlydirected spines, one on the frontal and one on the mesethmoid. It is also distinguishable from all other genera in the subfamily by the following combination of characters: head scales absent; squamation on body incomplete; maxillary expanded posteriorly; no thin pore-bearing skin flap over opercle; opercle thin, weak, without distinct spine; jaw teeth conical; vomerine and palatine teeth present; developed gill rakers on 1 st arch 3; pelvic fins with 1 ray in each; pectoral peduncle elongated, with 16 rays; caudal fin rays 12; branchiostegal, rays 8; precaudal vertebrae 15, with tips of 6th to 12th neural spines truncated.     

中国大陆沿海鲨鱼新纪录种

2006年3月中旬浙江省乐清县岐蒲镇渔民在中国东海南部(靠近台湾北部)海域捕获一条体长4 560 mm的鲨鱼.经鉴定为大口鲨Megachasma pelagios Taylor,Compagno et Struhsaker,1983,为我国大陆沿海鲨鱼1新纪录种.     

贵州高原鳅属鱼类二新种(鲤形目：鳅科：条鳅亚科)

描述高原鳅属鱼类2新种,即鼻须高原鳅Triplophysa nasobarbatula sp.nov.和贞丰高原鳅Triplophysa zhenfengensis sp.nov.,采自贵州省荔波县和贞丰县（均属西江水系）。前者与云南高原鳅Tripliophysa yunnanensis Yang相似,后者与鼻须高原鳅Triplophysa nasobarbatula sp.nov.相似,正模标本均保存在遵义医学院生物学教研室。     

Respiratory gill surface of the serrasalmid fish, Piaractus mesopotamicus

Gill element dimensions of pacu Piaractus mesopotamicus were estimated and correlated to body mass ( W ), according to the power equation Y=aW^b . The filament number ( b =0.154) and length ( b =0.457) increased with body mass, markedly influencing the respiratory gill surface area ( b =0.769). The high filament number and length, associated with a high secondary lamellae frequency ( a =40.21), are typical of active fish species and may be an adaptation to its migratory movements during reproduction. The comparatively small dimensions of its secondary lamellae are found more commonly in less active species, and may be related to the environmental conditions prevailing in lentic environments, where the species is normally found most of the year. Such features, together with its ability to compensate for oxygen reduction by means of a high ventilatory volume, and the use of aquatic surface respiration (ASR), may account for its adaptative capacity to withstand hypoxic conditions, with a low respiratory energy cost.     

Male Siamese fighting fish use gill flaring as the first display towards territorial intruders

The Siamese fighting fish (Betta splendens) is well known as an aggressive fish with unique spawning and parental care behavior. During reproduction, male fish construct a bubble nest, court females, protect the brood, and defend the territory through aggressive displays. Aggression in male Siamese fighting fish has long been the subject of investigation; however, the kinematics of aggression during contests have been largely overlooked. Here we investigated how nest-holding, male Siamese fighting fish use two different types of displays, gill flaring and fin spreading, towards intruders during various reproductive phases; before (BB) and after bubble nest building, and after spawning (AS), and hatching (AH). Males were more aggressive towards male than female intruders and the level of aggression changed significantly between reproductive phases. Gill flaring, the more energetically costly display, was the dominant initial display towards male and female intruders in BB, AS, AH phases. However, defending males switched to fin spreading after prolonged exposure to intruders. The results suggest that Siamese fighting fish use gill flaring as an acute response in order to defend their territory; this response may be replaced by fin spreading as a chronic response, probably to reduce the energetic costs during the contest.     

A new genus and species of prickleback (Perciformes: Stichaeidae) from Japan

A stichaeid fish, Xenolumpenus longipterus gen. et sp. nov., is described on the basis of 2 specimens (107.1–114.9 mm in standard length) collected from 167 to 300 m in the northern Sea of Japan off southern Hokkaido, Japan. Xenolumpenus is unique among all known genera of the subfamily Lumpeninae in having all pectoral, pelvic, and anal fin rays elongate and unbranched with fin membranes well-incised. Xenolumpenus longipterus can be further distinguished from all species of the subfamily in having the following combination of characters: dorsal fin XLVI–XLVIII; anal fin II, 28–29; pectoral fin 11; large black blotches on pectoral fin; and black ocellus on caudal fin.     

Morphometric examination of the gills of walleye, Stizostedion vitreum vitreum (Mitchill) and rainbow trout, Salmo gairdneri Richardson

Observations on the gill morphology of individual gill arches of walleye, Stizostedion vitreum vitreum and rainbow trout, Salmo gairdneri suggest that the first two arches account for the highest proportion of gill filament number, secondary lamellae number, lamellae area, and gill surface area. Interspecific comparisons suggest walleye contain a larger number of gill filaments, with a lower secondary lamellae count, but a larger gill surface area than a trout of the same weight. This is partially attributed to the larger surface area of each lamella in a walleye than in a trout.
A detailed examination suggests the surface area of a lamella is dependent on its position on the gill filament, and the position of the gill filament on the gill arch.     

New genus and species of the family stichaeidae from Hokkaido,Japan

Specimens of a new genus and species of the stichaeid fish,Leptostichaeus pumilus, were collected from the Okhotsk Sea off Hokkaido in Japan. The present new genus and species clearly differs from all the other genera and species of the stichaeid fishes in the following characters: 3 or 4 pectoral fin rays; 10 or fewer caudal principal rays; 79–82 dorsal spines; no pelvic fin; last interneural spine supporting a single dorsal spine; infraorbital, occipital and lateral line canals absent; moderate size of dorsal spine shorter than eye diameter; membranes of dorsal and anal fins widely connected with caudal fin; a large black spot divided by a yellow band present just above gill cover.     

Thyroid status alters gill ionic metabolism and chloride cell morphology as evidenced by scanning electron microscopy in a teleost Anabas testudineus (Bloch): short and long term in vivo study

Gill is the main organ of osmotic regulation in teleosts and chloride cells are the sites of ion transport across gill epithelium. Thyroid hormones are implicated in the regulation of osmotic balance in teleosts also. Treatment with 6-propyl thiouracil (6-PTU) inhibited the membrane bound enzyme Na+K+ ATPase in the gill while triiodothyronine (T3) injection stimulated it in a short-term in vivo study in the teleost Anabas testudineus. Na+, K+ and Ca2+ ions were also decreased in the 6-PTU treated fish and the T3 treatment increased their concentrations in the gill lamellae. The gill morphology also changed according to the thyroid status in the long term study. 6-PTU treatment altered the typical serrated morphology of the gill lamellae, while the T3 treatment reversed it. T3 injection increased the density of pavement and chloride cells as evidenced by scanning electron microscopy. The results demonstrate that physiological status of the thyroid influences gill Na+ pump activity and chloride cell morphological changes. Further, the study suggests a regulatory role of T3 on gill ions (Na+, K+ and Ca2+), Na+K+ and Ca2+ ATPase activity and the different gill cell types in A. testudineus.     

Gill Na(+)-K(+)-2Cl(-) cotransporter abundance and location in Atlantic salmon: effects of seawater and smolting

Na(+)-K(+)-2Cl(-) cotransporter abundance and location was examined in the gills of Atlantic salmon (Salmo salar) during seawater acclimation and smolting. Western blots revealed three bands centered at 285, 160, and 120 kDa. The Na(+)-K(+)-2Cl(-) cotransporter was colocalized with Na(+)-K(+)-ATPase to chloride cells on both the primary filament and secondary lamellae. Parr acclimated to 30 parts per thousand seawater had increased gill Na(+)-K(+)-2Cl(-) cotransporter abundance, large and numerous Na(+)-K(+)-2Cl(-) cotransporter immunoreactive chloride cells on the primary filament, and reduced numbers on the secondary lamellae. Gill Na(+)-K(+)-2Cl(-) cotransporter levels were low in presmolts (February) and increased 3.3-fold in smolts (May), coincident with elevated seawater tolerance. Cotransporter levels decreased below presmolt values in postsmolts in freshwater (June). The size and number of immunoreactive chloride cells on the primary filament increased threefold during smolting and decreased in postsmolts. Gill Na(+)-K(+)-ATPase activity and Na(+)-K(+)-2Cl(-) cotransporter abundance increased in parallel during both seawater acclimation and smolting. These data indicate a direct role of the Na(+)-K(+)-2Cl(-) cotransporter in salt secretion by gill chloride cells of teleost fish.     

Rosette glands in the gills of the grass shrimp,Palaemonetes pugio. I. Comparative morphology,cyclical activity,and innervation

Two types of exocrine rosette glands (called type A and type B), located in the gill axes of the grass shrimp Palaemonetes pugio, are described. The type A glands are embedded within the longitudinal median septum of the gill axes, whereas the type B glands typically project into the efferent hemolymph channels of the gill axes. Although both glands have certain common characteristics (i.e., a variable number of radially arranged secretory cells, a central intercalary cell, and a canal cell that forms the cuticular ductule leading to the branchial surface), they differ in the following respects. The type B gland is innervated, but the type A gland is not; axonal processes, containing both granular (ca. 900–1300 Å) and agranular (ca. 450–640 Å) vesicles, occur at a juncture between adjacent secretory cells and the central cell of the type B gland. The secretory cells of type A and type B glands differ in their synthetic potential and membrane specializations. These differences are more pronounced in well-developed, mature glands, most frequently encountered in larger (24–28 mm, total length) grass shrimp, than in the underdeveloped, immature glands that are most abundant in smaller (14–18 mm, total length) grass shrimp. Thus, in mature glands, the secretory cells of the type A rosette glands are characterized by extensive RER, abundant Golgi, and numerous secretory granules, whereas the secretory cells of the type B gland are characterized by extensively infolded and interdigitated basal plasmalemmas and by the presence of numerous mitochondria. In general, both types of glands exhibit increased secretory activity soon after ecdysis. The central and canal cells in both glands seem to have a role in the modification of the secreted materials. The possible functions assigned to the type A gland and the type B gland include phenol-oxidase secretion and osmoregulation, respectively.     

大仓鼠胁腺的发育及性别差异

通过对繁殖期雌雄大仓鼠胁腺重的比较研究发展雌雄鼠的胁腺重和体重分别存在正相关关系,非成年雌雄大仓鼠的胁腺重无显著性别差异,成年雄性大仓鼠的胁腺显著重于成年雌鼠,通过石蜡切片发现,雄鼠胁腺的皮脂细胞显著于雌鼠,对胁腺分泌物进行了气相色谱分析发现,雌雄胁腺分泌物的化学成分的种类和数量存在明显差异,本文从胁腺的形态,组织结构和化学成分三个方面初步揭示了胁腺在繁殖期具有性别别功能的机制。