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Two specimens of the peculiar squalid shark,Trigonognathus kabeyai gen. et sp. nov., were collected from the coastal waters of Wakayama and Tokushima, Japan, by bottom trawl at depths of 330 and 360 meters. Shape of teeth similar in both jaws; slender, unicuspid, canine-like, without any cusplets or serrations, with weak thin fold on both lingual and labial sides in anterior teeth on both jaws; tooth at symphysis of each jaw longest. Interspace between teeth very wide. Both jaws triangular in shape. Most of dermal denticles on body and head roughly rhombic, swollen very much near central part, with about 10–40 facets on the dorsal surface of its crown. Preoral snout length very short. Many small organs considered to be photophores present mainly on ventral surfaces of head and body.  相似文献   

3.
The oceanic abyss (depths greater than 3000 m), one of the largest environments on the planet, is characterized by absence of solar light, high pressures and remoteness from surface food supply necessitating special molecular, physiological, behavioural and ecological adaptations of organisms that live there. Sampling by trawl, baited hooks and cameras we show that the Chondrichthyes (sharks, rays and chimaeras) are absent from, or very rare in this region. Analysis of a global data set shows a trend of rapid disappearance of chondrichthyan species with depth when compared with bony fishes. Sharks, apparently well adapted to life at high pressures are conspicuous on slopes down to 2000 m including scavenging at food falls such as dead whales. We propose that they are excluded from the abyss by high-energy demand, including an oil-rich liver for buoyancy, which cannot be sustained in extreme oligotrophic conditions. Sharks are apparently confined to ca 30% of the total ocean and distribution of many species is fragmented around sea mounts, ocean ridges and ocean margins. All populations are therefore within reach of human fisheries, and there is no hidden reserve of chondrichthyan biomass or biodiversity in the deep sea. Sharks may be more vulnerable to over-exploitation than previously thought.  相似文献   

4.
Ifloga in southern Africa is revised and comments are offered on the northern hemisphere species, I. spicata (together with I. rueppellii ) and I. obovata. Twelve species are recognized in southern Africa, two being described as new. Two natural groups, based on floral characters, are recognized and the rank of subgenus is proposed for these. Ifloga spicata, I. obovata, I. glomerata, I. anomala, I. thellungiana and I. molluginoides constitute subgenus Ifloga; I. verticillata, I. polycnemoides, I. paronychioides, I. Candida, I. ambigua, I. repens, I. pilulifera, I. decumbens , subgenus Trichogyne. A key to the species is provided. The morphology and phytogeography of the genus are discussed.  相似文献   

5.
Gloeoporus guerreroanus sp. nov. is described and illustrated from specimens collected on bamboo in Rio Grande do Sul State, southern Brazil. The new taxon presents hymenium continuum along the tubular internal surface and dissepiments and represents an addition into the relatively small, poroid-merulioid genus Gloeoporus.  相似文献   

6.
Squaliformes comprise the major proportion of modern deep-water sharks, yet their fossil history and phylogenetic relationships are still poorly understood. New analyses have been undertaken, however, and new living and fossil species have been discovered during the past 10 years. A cladistic analysis involving 29 dental characters has been made and most living and fossil genera are included. On the basis of their dental morphology, the monophyly of the Squaliformes can be supported if the fossil genus Protospinax is excluded. The traditional phylogenetic positions of most living genera, Protosqualus, Cretascymnus and Eoetmopterus, are confirmed despite the fact that the Oxynotidae, Etmopterinae, Palaeomicroides, Proetmopterus and Microetmopterus have some atypical phylogenetic relationships within the Squaliformes. The addition of the palaeontological data in a phylogenetic tree including fossil and living Squaliformes demonstrates some gaps in the fossil record. Nevertheless, and as a consequence of that stratigraphy-phylogeny inference, two particular events can be pinpointed in the history of the Squaliformes: the first one occurs after the major Cenomanian-Turonian anoxic event and the second one after the Cretaceous/Tertiary crisis. The first radiation involves the majority of the living Squaliformes (Somniosinae, Centrophorinae, most of the Etmopterinae, Oxynotinae) in deep-sea waters, the second, the more epipelagic sharks (most of the Dalatiidae), suggesting a secondary adaptation to more shallow environments.  相似文献   

7.
A new eastern Pacific achirid, Trinectes xanthurus, has a distinctive yellow or light caudal fin, without pattern, to contrast with its relatively dark body. This species also has black, posterior margins of the dorsal and anal fins and 21-22 caudal vertebrae, versus 19-20 for its Pacific coast congeners. It usually is found in shallow, continental shelf waters on sand or mud bottoms and ranges from Colombia to El Salvador. The genus Trinectes is represented in the eastern Pacific by four species. A fifth species usually occurs in Pacific slope drainages (freshwater) in Panama. Of these species, only Trinectes fonsecensis is found throughout the tropical eastern Pacific, while the other three coastal species are confined to tropical waters south of the Golfo de Tehauntepec.  相似文献   

8.
Onychostoma minnanensis sp. nov. is described from tributaries of the Julong River in Fujian Province, China, based on morphological and mitogenetic evidence. It is characterized by the following unique combination of features: (1) a flexible and nonserrated last simple ray, (2) lateral-line scales always 41–44 modally 42 and predorsal scales 12 or 13 modally 12, (3) longer maxillary barbels in head length, (4) smaller cornified rostral cap with thick upper lip and lower part of upper lip exposed, and (5) coloration of young individuals with random grayish-black spots near or above lateral-line scales. Morphological surveys and mitochondrial DNA analyses reveal that O. minnanensis and Onychostoma barbatulum in the neighboring Min River Basin are the most closely related species.  相似文献   

9.
José L. Panero 《Brittonia》1996,48(2):192-194
A new species ofPassiflora subgenusTacsonia from the province of Zamora-Chinchipe, Ecuador, is described. The species is illustrated and its affinities to other species within the subgenus are discussed.  相似文献   

10.
The new species Ceratozamia vovidesii from a Pleistocene floristic refuge in southern Mexico is described and illustrated. It show an affinity with C. matudae Lundell and C. mirandae Vovides, Pérez-Farrera & Iglesias from Chiapas, but it differs from them in leaf, male and female cones, and trunk morphology.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 393–400.  相似文献   

11.
A new species belonging to the Dothideomycete genus Acanthostigma is described from bark of two Nothofagus species from Argentina. Its identity as a new species is based on both morphology and molecular sequence data. Acanthostigma patagonica differs from other species in the genus by having larger ascomata and setae and wider, asymmetrical ascospores. An amended key to Acanthostigma species is provided along with a discussion of other species previously described from South America.  相似文献   

12.
Forest or mouse shrews (Myosorex) represent a small but important radiation of African shrews generally adapted to montane and/or temperate conditions. The status of populations from Zimbabwe, Mozambique, and the north of South Africa has long been unclear because of the variability of traits that have traditionally been ‘diagnostic’ for the currently recognized South African taxa. We report molecular (mitochondrial DNA and nuclear DNA), craniometric, and morphological data from newly collected series of Myosorex from Zimbabwe (East Highlands), Mozambique (Mount Gorogonsa, Gorongosa National Park), and the Limpopo Province of South Africa (Soutpansberg Range) in the context of the available museum collections from southern and eastern Africa and published DNA sequences. Molecular data demonstrate close genetic similarity between populations from Mozambique and Zimbabwe, and this well‐supported clade (herein described as a new species, M yosorex meesteri sp. nov. ) is the sister group of all South African taxa, except for Myosorex longicaudatus Meester & Dippenaar, 1978. Populations of Myosorex in Limpopo Province (herein tentatively assigned to Myosorex cf. tenuis) are cladistically distinct from both Myosorex varius (Smuts, 1832) and Myosorex cafer (Sundevall, 1846), and diverged from M. varius at approximately the same time (2.7 Mya) as M. cafer and Myosorex sclateri Thomas & Schwann, 1905 diverged (2.4 Mya). Morphometric data are mostly discordant with the molecular data. For example, clearly distinct molecular clades overlap considerably in craniometric variables. On the other hand, extreme size differentiation occurs between genetically closely related populations in the Soutpansberg Range, which coincides with the bissection of the mountain range by the dry Sand River Valley, indicating the potential for strong intraspecific phenotypic divergence in these shrews. © 2013 The Linnean Society of London  相似文献   

13.
Silvinichthys huachi new species, is described from a stream along the lower slope of the Andean Cordillera in the Provincia de San Juan, Argentina. It shares the distinctive modifications characteristic of Silvinichthys, but is distinguished from the four previously described congeners by the combination of a lack of the pelvic fin and the pelvic girdle, details of pigmentation and various meristic and morphometric features. Silvinichthys huachi is apparently endemic to the type locality situated within an arid region of western central Argentina in the Andino Cuyana Province. Major gaps in the range of species of Silvinichthys may indicate that the origin of the genus predates the uplift events that subdivided drainages along the eastern slopes of the Andean Cordillera in west central Argentina. Silvinichthys huachi is hypothesized to be the sister species of Silvinichthys bortayro.  相似文献   

14.
A new species of the megaspiline genus Dendrocerus Ratzeburg is described and figured. Dendrocerus riograndensissp. n., is known from a series of males from the central region of Rio Grande do Sul, Brazil, and were captured with Malaise traps from an agricultural tobacco field.  相似文献   

15.
Ahmed S.  Thander 《Journal of Zoology》1989,219(4):637-644
A new species of a phyllophorid holothurian, Neothyonidium arthroprocessum, is described from the shallow waters of False Bay, South Africa. The new species is distinct from other phyllophorids in possessing peculiar narrow transverse slits in the body wall, a calcareous ring with joined posterior processes to the radial plates, and short thick perforated rods as body wall deposits. The diagnosis of the genus Neothyonidium is amended to accommodate the new species.  相似文献   

16.
Ceratozamia chimalapensis sp. nov. is described and illustrated. It is related to C. mirandae Vovides, Pérez-Farrera & Iglesias from Chiapas, but differs in trunk and peduncle size as well as in diameter of both megastrobili and microstrobili. Petiole, megasporophyll and indument colour also differ from that of C. mirandae . Ceratozamia chimalapensis forms part of the C. norstogii D.W.Stev. species complex, a group of ceratozamias with narrow leaflets growing in the herbaceous layer of oak forests in southern Mexico. These forests were severely affected by forest fires during 1998 and we recommend an IUCN Red List Category of CR B.1. Speciation in Ceratozamia has been discussed in the light of floristic refugia.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 169–175.  相似文献   

17.
A new species of Physophora, belonging to the physonect family of siphonophores Physophoridae is described. It can easily be distinguished from the only other recognised species in that family, P. hydrostatica, by the presence of two types of bracts. The arrangement of the palpons and bracts throws new light on the cormidial organisation of the physophorids, and comparisons are made between both species. The validity of an enigmatic physophorid species, Discolabe quadrigata, is discussed.  相似文献   

18.
Desmanthodium congestum, a new species from Chiapas, Mexico, is described and illustrated. Its morphological features are clearly distinguishable from other species of the genus, so much so that this taxon forms a new subgenus withinDesmanthodium, subgenusMultiaggregata.  相似文献   

19.
Ceratozamia euryphyllidia from Veracruz is described and illustrated. This species differs from all others in the genus in its very large, broad leaflets (9–16 cm wide) which have undulate margins, prominent veins, and a membranous to translucent texture at maturity. It is apparently related to a group of species which all have relatively small strobili and leaflets that are attenuate basally, oblanceolate to obovate, inequilateral, abruptly acuminate apically, and generally papyraceous to membranaceous. The allopatric species of this group inhabit moist to very wet areas. The wetter the habitat, the larger and thinner the leaflets. Thus, for example,C. latifolia which has the smallest leaflets grows in the driest habitat whereasC. euryphyllidia which grows in the wettest habitat has the largest leaflets in the genus.  相似文献   

20.
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