首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
The ecology, feeding habits and sexual dimorphism in Arabian Sand Boa, Eryx jayakari from the Central region of Saudi Arabia, were studied. In this study the E. jayakari was recorded for the first time from several sites. Significant differences were noted in total length of body and tail, and body diameter of male and female. The females were of larger size. The mean number of the dorsal body scales, ventrals and subcaudal for both sexes were not significantly different. The mean number of the dorsal body scales, ventral body scales and subcaudal scales for the females was 43, 169 and 18 scales which were not significantly different from respectively ones in males 42, 168 and 18 scales. Frequent prey consumed were lizards (50%), rodents (25%) and arthropods (12.5%).  相似文献   

2.
In two species of Heterodontus, H. portusjacksoni and H. galeatus, the first scales to develop form two opposing rows along the caudal fin axis on both the left and right sides of the fin. The opposing rows originate from an initial scale located on either side of the posterior tip of the caudal fin, with subsequent scales erupting in a posterior to anterior direction along the tail axis. These scale rows may strengthen tail movements, providing aeration in the egg case, but are lost later in ontogeny. Development of subsequent body scales shows a more irregular origin and arrangement, from anterior to posterior, to cover the dorsal and ventral lobes of the caudal fin. Although the early developmental pattern of the scale associated with the Heterodontus caudal fin has not been previously described, several chondrichthyan taxa, including chimeroids, likewise possess ordered rows of flank scales early in ontogeny that are subsequently lost. These ordered scales contrast with previous suggestions that chondrichthyan scale development is entirely random. Instead, regulated and sequential development of scales may be a plesiomorphic character for both chondrichthyans and osteichthyans, with the less organized arrangement in later ontogenetic stages being a derived condition within Chondrichthyes.  相似文献   

3.
We review the distribution, morphology and taxonomic status of Eryx elegans, E. jaculus, E. miliaris, E. tataricus and E. johnii in Iran and examine four metric and 10 meristic characters of 94 specimens from different parts of the country. There are significant morphological differences between Eryx tataricus, E. jaculus and E. elegans, mainly in snout vent length, tail length, and number of ventrals, subcaudals and dorsal scales. Eryx jayakari and E. johnii can easily be distinguished based on their morphological traits and limited distribution in Iran. The occurrence of E. miliaris in Iran was not confirmed. The Iranian populations of Eryx jaculus are assigned to the subspecies E. j. turcicus. E. jaculus specimens from southwestern Iran had higher ventral scales than other populations, so evaluating their taxonomic status needs genetic studies in the future. A distribution map and a revised key to the genus Eryx in Iran are presented.  相似文献   

4.
The Halieutichthys aculeatus species complex is reviewed. Members of this clade are distinguished by the presence of tubercles on the tail and a reticulate dorsal pigmentation pattern. Three species are recognized, including two species new to science. A neotype is chosen for H. aculeatus. Halieutichthys bispinosus n. sp. is characterized by having relatively strong tubercles on the dorsal surface, a row of tubercles almost always present dorsal to the orbit, both sphenotic tubercles well developed and sharp, trifid principal tubercles on the disk margin with anterior spinelet enlarged, dense arrangement of tubercles on the tail and a comparatively large adult body size. Halieutichthys intermedius n. sp. can be distinguished from congeners by having both sphenotic tubercles strongly reduced, the tubercles almost always absent dorsal to the orbit, principal tubercles on the disk margin uniformly short and blunt tubercles, with all spinelets generally reduced.  相似文献   

5.
Regular scale patterning, restricted to the caudalmost tail and organized into two opposing rows on each side of the tail, is observed in few chondrichthyans. These evenly spaced scales, in dorsal and ventral rows, develop in an iterative sequence from the caudal tip, either side of the notochord. They are subsequently lost as a scattered pattern of placoid scales develops on the body and fins. An identical organized pattern is observed in tail scales of Scyliorhinus canicula (catshark), where the expression of sonic hedgehog signal is restricted to the epithelium of developing scales and remains localized to the scale pocket. Regulation of iterative scale position by sonic hedgehog is deeply conserved in vertebrate phylogeny.These scales also reveal an archaic histological structure of a dentine type found in the oldest known shark scales from the Ordovician and Silurian. This combination of regulated pattern and ancient dentine occurs only in the tail, representing the primary scalation. Scattered body scales in elasmobranchs such as S. canicula originate secondarily from differently regulated development, one with typical orthodentine around a central pulp cavity. These observations emphasize the modular nature of chondrichthyan scale development and illustrate previously undetected variation as an atavism in extant chondrichthyan dentine.  相似文献   

6.
The legless locomotion of snakes requires specific adaptations of their ventral scales to maintain friction force in different directions. The skin microornamentation of the snake Corallus hortulanus was studied by means of scanning electron microscopy and the friction properties of the skin were tested on substrates of different roughness. Skin samples from various parts of the body (dorsal, lateral, ventral) were compared. Dorsal and lateral scales showed similar, net-like microornamentation and similar friction coefficients. Average friction coefficients for dorsal and lateral scales on the epoxy resin surfaces were 0.331 and 0.323, respectively. In contrast, ventral scales possess ridges running parallel to the longitudinal body axis. They demonstrated a significantly lower friction coefficient compared to both dorsal and lateral scales (0.191 on average). In addition, ventral scales showed frictional anisotropy comparing longitudinal and perpendicular direction of the ridges. This study clearly demonstrates that different skin microstructure is responsible for different frictional properties in different body regions.  相似文献   

7.
A new Anolis species of the Alpha section from the north region of eastern Cuba (Holguín province) is described. It differs from all Cuban species of Anolis in its green coloration with greenish gray bands on body, legs and tail, in having subtriangular mental scales as well as in other details of color and scutellation. This new species is most closely related to A. isolepis but it can be distinguished from both, A. i. isolepis and A. i. altitudinalis, by its coloration and pattern, the larger body size, the presence of smooth ventral scales (similar in size to the dorsal scales) and by the absence of enlarged postcloacal scales in the male.  相似文献   

8.
A new cottid species,Icelus ecornis, is described on the basis of 31 specimens collected from 159–226 m in the southwestern Okhotsk Sea off Hokkaido, Japan. It is distinguished from all other members of the genusIcelus by the following combination of characters: no supraocular and parietal spines; short blunt nuchal spine; cirri absent from head and body, except for supraocular, parietal and nuchal regions; platelike scales of dorsal row bearing 6–10 long uniform spinules; tubular lateral line scales bearing small spines on dorsal and posterior margins; large oval black spot on first dorsal fin; 16–20 anal fin rays.  相似文献   

9.
The Oberhautchen of scales from the dorsal, parietal, and ventral regions of Sceloporus occidentalis (Iguanidae), Gerrhonotus multicarinatus (Anguinidae), and Anniella pulchra (Anniellidae) were examined with a scanning electron microscope. At low magnification, all scales of S. occidentalis exhibit well-defined outlines of cells belonging to the Oberhautchen layer and the previously overlying clear layer. The dorsal and parietal cells of this species exhibit a minutely dentate Oberhautchen that forms tooth-like spinules 0.2 to 0.5 μ long and arranged in irregular rows. Minute pits 0.1 to 0.3 μ in diameter characterize the Oberhautchen of a ventral scale. Cell outlines are not evident on the scales of G. multicarinatus. The Oberhautchen of dorsal and parietal scales of this species is prominently laminated. Laminae are less prominent on scales of the lateral fold, and no intrinsic surface structure is evident on a ventral scale. In contrast, the fossorial anguinomorph Anniella pulchra exhibits Oberhautchen surfaces with practically no intrinsic microornamentation. However, what appear to be outlines of Oberhautchen cells are visible on the dorsal and ventral scales. These observations suggest that modifications of Oberhautchen microornamentation may have evolved to reduce friction with the substrate or other scales. The lack of pronounced microornamentation of the Oberhautchen on some body scales may indicate that a complex interdigitation between clear layer and Oberhautchen cells is not essential to the sloughing process.  相似文献   

10.
11.
Osteoderms are bone‐rich organs found in the dermis of many scleroglossan lizards sensu lato, but are only known for two genera of gekkotans (geckos): Tarentola and Gekko. Here, we investigate their sequence of appearance, mode of development, structural diversity and ability to regenerate following tail loss. Osteoderms were present in all species of Tarentola sampled (Tarentola annularis, T. mauritanica, T. americana, T. crombei, T. chazaliae) as well as Gekko gecko, but not G. smithii. Gekkotan osteoderms first appear within the integument dorsal to the frontal bone or within the supraocular scales. They then manifest as mineralized structures in other positions across the head. In Tarentola and G. gecko, discontinuous clusters subsequently form dorsal to the pelvis/base of the tail, and then dorsal to the pectoral apparatus. Gekkotan osteoderm formation begins once the dermis is fully formed. Early bone deposition appears to involve populations of fibroblast‐like cells, which are gradually replaced by more rounded osteoblasts. In T. annularis and T. mauritanica, an additional skeletal tissue is deposited across the superficial surface of the osteoderm. This tissue is vitreous, avascular, cell‐poor, lacks intrinsic collagen, and is herein identified as osteodermine. We also report that following tail loss, both T. annularis and T. mauritanica are capable of regenerating osteoderms, including osteodermine, in the regenerated part of the tail. We propose that osteoderms serve roles in defense against combative prey and intraspecific aggression, along with anti‐predation functions. J. Morphol. 276:1345–1357, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   

12.
The integument of the paddlefish (Polyodon spathula) is unusual as a relatively small amount of mucus is produced by epithelial cells that are not modified into regular mucous gland cells. A thick compact epidermis and dermis compensate for the slight amount of mucus secreted. Paddlefish have a variety of scales formed of concentric bony lamellae containing osteocytes. There are five kinds of scales: dorsal and ventral fulcra on the caudal fin, rhomboidal scales on the caudal lobe, horny denticles over the pectoral girdle, calcareous denticles on the trunk, and anchor-shaped plates on the rostrum. Except for the fulcra, the scales are undoubtedly vestigial. The numerous surface pits on the rostrum, head, operculum, and throat are epithelial invaginations which are not connected to lateral line canals. No nerves lead to the pits. The spherical to cuboidal and often ciliated cells at the base of the pits are considered to be aplasic cells of unformed neuromasts.  相似文献   

13.
Three species of the soldierfish genusOstichthys have been collected in the Society Islands at depths of 300–420 m:O. archiepiscopus andO. sandix are new records for the South Pacific, andO. ovaloculus is described as new from one specimen taken off Tahiti. It is distinctive in having XI, 16 dorsal rays, 15 pectoral rays, 38 lateral-line scales (other species of the genus with 27–30), 31/2 rows of scales above the lateral line, a straight dorsal head profile, long snout, and oval eye; color when fresh, bright red, the centers of scales whitish, resulting in longitudinal banding on the body.  相似文献   

14.
Tang XS  Lu SQ  Chou WH 《Zoological science》2007,24(5):496-503
The Chungan ground lizard, Takydromus sylvaticus, long known only from five females collected in Fujian Province of China, was recently found in Anhui Province of the country. The newly collected specimens included the first male specimens (n=7), in which the tail bases were stouter than in conspecific females. Ventral scales in these males were invariably keeled, whereas in females those forming the four median rows were smooth. Females had more dorsal scales (47-48) than males (42-43) in the median longitudinal row between axilla and groin. Takydromus sylvaticus differed from the closely related T. dorsalis in having more dorsal scales in the median longitudinal row between axilla and groin (42-48 versus 32-40, respectively), more rows of large dorsal scales between the hind legs (10 versus 7-8, respectively), shorter hind legs, two distinct white longitudinal stripes on each side of the body, and no black stripe in the preocular and postocular regions. The number of transverse rows of ventral scales between collar and femoral pores in T. sylvaticus (26-28) was larger, but with a slight overlap, than that in T. dorsalis (22-26). Ecological observations on T. sylvaticus were also documented.  相似文献   

15.
Pethia sanjaymoluri, a new cyprinid, is described from the Pavana and Nira tributaries of Bhima River, Krishna drainage, Maharashtra, India. It can be distinguished from congeners by a combination of characteristics that includes an incomplete lateral line, absence of barbels, upper lip thick and fleshy, 23–25 lateral series scales, 7–12 lateral‐line pored scales, 10 predorsal scales, 11–14 prepelvic scales, 17–20 pre‐anal scales, 4½ scales between dorsal‐fin origin and lateral line, four scales between lateral line and pelvic‐fin origin, 8–15 pairs of serrae on distal half of dorsal‐fin spine, 12–14 branched pectoral‐fin rays, 4 + 26 total vertebrae, 4 + 5 predorsal vertebrae, 4 + 13 abdominal vertebrae, 13 caudal vertebrae and a unique colour pattern comprising a humeral spot positioned below the lateral line and encompassing the third and fourth lateral‐line scales and one scale below, one caudal spot on 17th–21st lateral‐line scales with a yellow hue on its anterior side and apical half of dorsal fin studded with melanophores making the fin tip appear black. Genetic analysis based on the mitochondrial cytochrome b gene sequence suggests that the species is distinct from other known species of Pethia for which data are available.  相似文献   

16.
Witzmann F. (2011). Morphological and histological changes of dermal scales during the fish‐to‐tetrapod transition. —Acta Zoologica (Stockholm) 92 : 281–302. The gastral scales of limbed tetrapodomorphs evolved from the ‘elpistostegid’‐type of scale by an enlargement and differentiation of the articulation facets and a shortening and broadening of the keel. These changes caused a tighter connection between gastral scales within a scale row and a greater overlap between the rows. Dorsal round scales of limbed tetrapodomorphs developed from a gastral scale‐type by an alteration of the ontogenetic pathway. The posterolateral direction of scale rows in ‘elpistostegids’ was retained in the gastral scalation of most limbed tetrapodomorphs, whereas the arrangement of round dorsal scales is modified to a transverse orientation. Both gastral and dorsal scales of limbed tetrapodomorphs consist solely of parallel‐fibred bone with circumferential growth marks. The proportionally larger overlap surfaces of gastral scales and their mode of articulation in the ventral midline indicate that the body of limbed tetrapodomorphs might have been more flexible than that of their finned relatives. The alteration of dermal scales was one of the most rapid morphological changes during the fish‐to‐tetrapod transition. Once established, gastral and dorsal scales were retained as a conservative character in different lineages of basal tetrapods, in both the amphibian and the amniote lineages.  相似文献   

17.
Two new species of the sciaenid genusJohnius (Johnius) are described:J. trewavasae from Taiwan, Hong Kong, and Singapore, differs from all other congeners in having 24–27 dorsal soft rays, 5–6 scales above and 7–10 scales below the lateral line, 6–8 obtuse lower gill rakers, the last pleural rib on the 11th vertebra, and a shorter lower jaw (33.8–38.4% HL);J. latifrons from Thailand and Java is characterized by 25–29 dorsal soft rays, 7–9 scales above and 11–14 scales below the lateral line, 7–9 obtuse lower gill rakers, a wide interorbital width (26.1–30.6% HL), a small eye (16.7–26.4% HL), and a short, second anal spine (25.9–37.1% HL). Two related species,J. heterolepis Bleeker from “Suriname” andJ. cantori Bleeker from Malaya, are resurrected as valid West Pacific species of Johnius (Johnius).  相似文献   

18.
Predation has profound effects on the phenotypes of animal prey and, in lizards, the relationship between coloration and antipredatory behaviour has been studied in depth. However, studies that address the relationships between dorsal patterns and tail coloration with escape behaviour in polymorphic lizards are absent in the literature. We describe dorsal morphs and measured tail coloration and escape behaviour in hatchling Iberian wall lizards, Podarcis hispanicus, a species with a previously undescribed female‐restricted dorsal polymorphism (reticulated‐blotched males, and either striped or reticulated‐blotched females) and juvenile tails with conspicuous blue coloration, which is probably used to divert predator attacks towards the autotomizable tail. Overall we provide evidence for the existence of sexual dimorphism in tail ultraviolet reflectance between reticulated females and males, with striped females being intermediate. We identified sex/dorsal morph, body size and tail brightness as predictors of different aspects of escape behaviour and suggest the existence of two alternative escape strategies between striped and reticulated‐blotched females that may be dependent on dorsal morph differences, independently of sex. Reticulated‐blotched females, and also males (all reticulated‐blotched), ran faster and spent less time paused than striped females, which might reflect an escape behaviour strategy based on endurance in striped females. In addition, lowland males displayed tail waving as a ‘last resort’ antipredator strategy that may be related to fatigue. We concluded that hatchling antipredatory behaviour is influenced by both dorsal pattern and tail conspicuousness. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 1094–1106.  相似文献   

19.
A new sciaenid,Johnius (Johnieops) philippinus, is described from the Davao Gulf, Mindanao Island Philippines. It differs from all known species of the subgenus in the combination of 29–32 dorsal fin soft rays, 5–6 scales above and 10–13 scales below the lateral line, 10–12 lower gill rakers, a broadly rounded anterior snout margin (from dorsal aspect), large eyes (28–35% HL), a narrow interorbital space (23–28% HL) and well-developed pleural ribs on 11th vertebra. A synopsis of species included in the subgenusJohnieops is provided.  相似文献   

20.
西藏沙蜥属一新种—泽当沙蜥   总被引:4,自引:0,他引:4  
根据形态特征,泽当居群与西藏沙蜥、红尾沙蜥有显著区别,为沙蜥属一新种:泽当沙蜥Phrynocephalus zetangensis sp.nov.Wang,Zeng et Wu鉴别特征为鼻鳞1枚;鼻间鳞4-5枚;背鳞数少于腹鳞数;雄性尾末端黑色,雌性灰白色。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号