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 15 毫秒
1.
This paper continues a former study (Rev. Española Micropaleontol. 14 (1982b) 401), where the author described spicular nassellarian and entactinarian Radiolaria found in the Middle Triassic samples available at that time. Based on the study of new samples bearing well preserved radiolarians collected during the 20 years that followed the former publication, samples coming from Triassic, Jurassic, Cretaceous, and Paleogene deposits, the author found that spicular Nassellaria are extremely rare in the post-Fassanian radiolarian faunas. Their fossil record is punctuated, their occurrences being separated by very long gaps. And even so, when they occur their number is usually reduced to one, two, or several specimens of a single species. Spicular Nassellaria are rare or very rare in the upper Spathian and Anisian, frequent in the upper Anisian-lower Ladinian, practically absent in the upper Ladinian and the whole upper Triassic and pre-Toarcian Lower Jurassic, rare in lower Toarcian, very rare in the Bajocian, rare in the lower Tithonian. No specimens were recorded in the other stages of the middle and upper Jurassic and in the whole Cretaceous, except for one in the Coniacian. In the Paleogene only five species belonging to four genera have been recorded in the upper Paleocene-middle Eocene. In the Neogene the only genus known so far is Neosemantis that occurs sporadically since the lower Miocene. A wider diversity is recorded in the living plankton or Recent sediments that comprise all genera and species described in the literature before 1970. It is suggested that this scarcity reflects their real scarcity in the tropical or subtropical seas of the past, but this scarcity was probably magnified by selective preservation. The idea of origination of spicular Nassellaria once or several times from shell-bearing Nassellaria by the reduction of shell during some environmental crises of the Mesozoic and Cenozoic or by hybridization is rejected because the group is rather unitary in its spicular structure and it shows a certain evolution from taxa with massive spines to taxa with three-bladed spines. Nassellarian-like spicular Radiolaria range within the boundaries of the Triassic; they seem to have disappeared by the end on the Norian.In order to give a complete inventory of these radiolarians all taxa known in the Mesozoic and lower Cenozoic are described, discussed, or just mentioned. They comprise 44 species of which 20 are new, 14 genera of which six are new (Palaeosemantis, Molzaxis, Daniplagia, Verticiplagia, Jeanpierria and Nandartia), three subfamilies of which one (Zaldacriinae) is new, and two families (Plagiacanthidae and Archaeosemantidae).  相似文献   

2.
Based on light and scanning electron microscopical studies, a new nematode parasite, Lobocapillaria austropacifica n. sp. (Capillariidae), is described from the gall-bladder of the marine fish (obtuse barracuda) Sphyraena obtusata Cuvier (Perciformes: Sphyraenidae) from off the eastern Pacific coast of Australia, for which a new genus Lobocapillaria n. g. is established. This new genus is mainly characterised by a single row of stichocytes, the presence of two large, conspicuously elongated lateral caudal lobes and a pair of subventral papillae at their base in males, a flat spicule distended laterally towards its proximal end and provided with superficial rough transverse grooves, a spicular canal and a very long, aspinose spicular sheath with a conspicuous expansion near its proximal end when evaginated. Capillaria sphyraeni Parukhin, 1971 is transferred to Lobocapillaria as L. sphyreni (Parukhin, 1971) n. comb. A key to capillariid genera containing species parasitic in fishes is provided.  相似文献   

3.
A new genus and species of deep-sea eelpout (Zoarcidae), Barbapellis pterygalces, is herein described from a single adult female specimen carrying eggs and measuring 204 mm in total length. It was collected on the eastern Antarctic continental slope, off Terre Adélie, at ca. 1,200 m depth, on muddy bottom. Barbapellis is placed in the subfamily Gymnelinae and can be distinguished from all other genera by morphological characters unusual in zoarcids as well as by molecular barcoding. The genus is characterized by the presence of a complex system of cephalic skin crests and flaps, especially well developed around the mouth. A new terminology is proposed for the eleven crests and sevenfolds described. The skin folds may be used for foraging on muddy sea bottoms. The genus is also characterized by large, flexible, and highly palmate pectoral fins. The designation of the new genus is discussed.  相似文献   

4.
A new nematode from the stomach of the estuarine fish Sillaginopsis panijus of West Bengal, India is described. The nematodes are characterised by small body size, the structure of the male tail (the presence of two large dorso-lateral caudal lobes bearing a distinct papilla on each and a pair of large subventral adanal papillae), the structure of the spicule (wider in proximal and distal regions and with smooth surface), the non-spinous spicular sheath, the structure of the stichosome (stichocytes number 25–32 and regularly aligned throughout the length of the oesophagus), the large bell-shaped vulvar appendage, and elongate-oval eggs with a thin wall and protruding polar plugs. A diagnosis of the new genus and a key to the genera of fish capillariids are provided.  相似文献   

5.
The fine structure of the cuticle in the archiannelids Polygordius, Protodrilus, Trilobodrilus, and Diurodrilus is described. Polygordius and Protodrilus are unique with respect to the filiform microvilli penetrating through the cuticle. Basically all forms conform to the most common type of cuticular structure in the Annelida: a fibrous matrix of varying complexity penetrated by micro-villar-like cell processes. Following the ideas expressed by Lyons (1970), a hypothesis on the evolution of the cuticle within the vermiform Spiralia (e.g. Turbellaria, Nemertea, Annelida) is proposed. New data on interstitial Turbellaria and other new forms of interstitial worms suggest a morphological and functional sequence from the multiciliated epidermis of Turbellaria to the cuticularized hypodermis of Annelida.  相似文献   

6.
The marine red algal family Liagoraceae sensu lato is shown to be polyphyletic based on analyses of a combined rbcL and psaA data set and the pattern of carposporophyte development. Fifteen of eighteen genera analyzed formed a monophyletic lineage that included the genus Liagora. Nemalion did not cluster with Liagoraceae sensu stricto, and Nemaliaceae is reinstated, characterized morphologically by the formation of the primary gonimolobes by longitudinal divisions of the gonimoblast initial. Yamadaella and Liagoropsis, previously placed in the Dermonemataceae, are shown to be independent lineages and are recognized as two new families Yamadaellaceae and Liagoropsidaceae. Yamadaellaceae is characterized by two gonimoblast initials cut off bilaterally from the fertilized carpogonium and diffusely spreading gonimoblast filaments. Liagoropsidaceae is characterized by at least three gonimoblast initials cut off by longitudinal septa from the fertilized carpogonium. In contrast, Liagoraceae sensu stricto is characterized by a single gonimoblast initial cut off transversely or diagonally from the fertilized carpogonium. Reproductive features, such as diffuse gonimoblasts and unfused carpogonial branches following postfertilization, appear to have evolved on more than one occasion in the Nemaliales and are therefore not taxonomically diagnostic at the family level, although they may be useful in recognizing genera.  相似文献   

7.
Growth of the invasive algae Caulerpa racemosa var. cylindracea in shallow habitats may influence the faunal assemblage composition. We studied its effects on caprellid assemblages associated with shallow-water habitats of hard and soft bottoms from the SE Iberian Peninsula (native rocky-bottom algae, C. racemosa from hard and soft bottoms, and Caulerpa prolifera, Cymodocea nodosa and Posidonia oceanica from soft bottoms). Samples were taken in two different sampling periods (September 2004 and March 2005). A total of seven caprellid species were identified, with important differences in their distribution in different habitats. Total abundance of caprellids was very high in March on native algae on hard bottoms, and on C. racemosa on both soft and hard bottoms. On both hard and soft bottoms, abundances of Caprella hirsuta recorded from C. racemosa were low. On the other hand, a higher abundance of other species, namely C. acanthifera, C. santosrosai, Phtisica marina and Pseudoprotella phasma, was recorded from C. racemosa. The results indicate that C. racemosa may have a positive influence on some caprellid species, while seasonal changes are also evident. It is concluded that introduced C. racemosa may serve as a new habitat, promoting and maintaining caprellid populations in shallow Mediterranean habitats.  相似文献   

8.
Morphological and molecular studies demonstrate that the tribe Ptiloteae (Ceramiaceae, Ceramiales) is polyphyletic. The Ptiloteae, sensu stricto, occur only in the Northern Hemisphere and all Southern Hemisphere representatives belong in other tribes. Three genera (Euptilota, Seirospora, and Sciurothamnion) are transferred to the Euptiloteae Hommersand et Fredericq, trib. nov., and the Callithamnieae is revised to include three Ptilota‐like genera, Georgiella, Falklandiella, and Diapse, and two new genera. Heteroptilon Hommersand, gen. nov. is erected to receive Euptilota pappeana Kützing 1849 and Aglaothamnion rigidulum De Clerck, Bolton, Anderson et Coppejans 2004 from South Africa, and Aristoptilon Hommersand et W. A. Nelson, gen. nov. is established to receive Euptilota mooreana Lindauer 1949 from New Zealand. The principal difference between the Euptiloteae and the Callithamnieae is seen in the earliest stages after fertilization. The fertilized carpogonium enlarges and forms a pair of tube‐like protuberances directed toward the auxiliary cells that are cut off as connecting cells in the Euptiloteae, whereas in the Callithamnieae the carpogonium usually divides into two cells, each of which cuts off a small connecting cell that fuses with an adjacent enlarging auxiliary cell. Nuclei are terminal in spermatangia of the Euptiloteae, subtended by mucilaginous vesicles, and are medial in the Callithamnieae situated between apical and basal vesicles. The Euptiloteae and Callithamnieae (including the Ptilota‐like members) are each strongly supported in maximum‐likelihood tree topologies resulting from analyses of combined 18S rDNA, 28S rDNA, 16S rDNA, and rbcL data sets. Their sister relationship is also well supported.  相似文献   

9.
A new lacazelline brachiopod species is described from reef caves in the outer reef slope zone off Addu and South Male atolls in the Maldive Islands, Indian Ocean. Based on anatomical features of the soft parts, shell morphology and shell microstructure the new taxon is assigned to the genus Ospreyella Lüter and Wörheide 2003 in the subfamily Lacazellinae of the family Thecideidae. This new species, here named O. maldiviana and representing the first occurrence of the genus in the Indian Ocean, is compared with the type species O. depressa Luter from Osprey Reef, Coral Sea, Australia. Comparisons are made between Ospreyella (now two species) and the other extant lacazelline genera Lacazella Munier‐Chalmas (three species) and Pajaudina Logan (one species).  相似文献   

10.
A new genus and species of didymozoid digenean is described from the skipjack tuna Katsuwonus pelamis (Linnaeus) in the Southwest Atlantic Ocean off Brazil. Pozdnyakovia gibsoni n. g., n. sp. is placed in the Gonapodasmiinae Ishii, 1935. The new genus differs from other genera in the morphology of the posterior regions of the fused pair; this consists of an unlobed, rounded mass fused only dorsally and with a large, elliptical ventral aperture opening into a longitudinal deep cavity from which emerge the two elongate anterior regions. It also differs in the form of the testes, which form two sets of three to four branches in each partner.  相似文献   

11.
The Turbellaria fauna has been studied in the Uvod’ Reservoir. A total of 18 species have been found representing three orders: Catenulida, Macrostoimida, and Neorhabdocoela. The patterns of Turbellaria distribution in the reservoir have been analyzed. The most abundant species have been determined: Stenostomum leucops Duges, 1828, Microstomum lineare (O.F. Müller, 1774), Bothromesostoma essenii M. Braun, 1885, and Mesostoma lingua (Abildgaard, 1789).  相似文献   

12.
A molecular survey of red algae collected by technical divers and submersibles from 90 m in the mesophotic zone off the coast of Bermuda revealed three species assignable to the Kallymeniaceae. Two of the species are representative of recently described genera centered in the western Pacific in Australia and New Zealand, Austrokallymenia and Psaromenia and the third from the Mediterranean Sea and the eastern Atlantic, Nothokallymenia. A phylogenetic analysis of concatenated mitochondrial (COI‐5P) and chloroplast (rbcL) genes, as well as morphological characteristics, revealed that two are shown to be new species with distant closest relatives (N. erosa and Psaromenia septentrionalis), while the third represents a deep water western Atlantic species now moved to an Australasian genus (A. westii).  相似文献   

13.
Vegetative and reproductive morphology and ultrastructure were examined for the three genera of the freshwater red algal family Lemaneaceae: Lemanea (two species, seven populations), Paralemanea (two species, three populations) and Psilosiphon (one species, one population). Psilosiphon is readily distinguished from the other two genera in having an outer cortex composed of well-defined filaments interconnected with a dense medulla (both cell types being little vacuolated), spores cleaving off obliquely, putative spermatangia scattered on the thallus surface and reproduction by adventitious filaments. Based on the distinctness of this genus (and corroborated by molecular phylogenies in preparation), a new family is described, the Psilosiphonaceae. Lemanea and Paralemanea appear to be closely related, with an outer cortex that has cells of increasing size and vacuolation from the periphery to the interior and not in obvious rows, a central lumen that contains few ray cells but no medullary filaments, sexual reproduction with spermatangia in distinct clusters, and carpospores in chains, some of which can germinate in the thallus lumen. Lemanea and Paralemanea have distinguishing characteristics that the other genus does not: for Lemanea, hair cells, ray cells abutting the outer cortex and spermatangia in patches; for Paralemanea, no hair cells or ray cells appressed to the outer cortex, inner cortical filaments surrounding the central axis and spermatangia in rings.  相似文献   

14.
Cutmore  S. C.  Yong  R. Q.-Y.  Reimer  J. D.  Shirakashi  S.  Nolan  M. J.  Cribb  T. H. 《Systematic parasitology》2021,98(5-6):641-664

Ankistromeces Nolan & Cribb, 2004 and Phthinomita Nolan & Cribb, 2006 are sister genera of threadlike blood flukes (Trematoda: Aporocotylidae) infecting teleost fishes of the tropical Indo-west Pacific. Here, we report new collections of these genera from Australia, Indonesia, and Japan. A new species of Ankistromeces, Ankistromeces kawamurai n. sp., is described from Siganus spinus (Linnaeus) off Okinawa, Japan, and a new species of Phthinomita, Phthinomita abdita n. sp., from Choerodon cephalotes (Castelnau), in Moreton Bay, Australia; the new species are morphologically cryptic within their respective genera and are delineated by molecular and ecological data. Ankistromeces olsoni Nolan & Cribb, 2006 is reported from Siganus fuscescens (Houttuyn) off Heron Island (southern Great Barrier Reef), Lizard Island (northern Great Barrier Reef), and Okinawa and Wakayama Prefectures, Japan and from Siganus spinus (Linnaeus) from off Bali, Indonesia. Ankistromeces mariae Nolan & Cribb, 2004 is re-reported from the type-host, Meuschenia freycineti (Quoy & Gaimard), from a new location, Gypsy Bay, Tasmania. Phthinomita poulini Nolan & Cribb, 2006 is re-reported from its type-locality, Lizard Island, from a range of mullids, including five new host species, and its range is extended to include Moreton Bay. Phthinomita symplocos Nolan & Cribb, 2006 is reported from Bali and P. hallae Nolan & Cribb, 2006, P. jonesi Nolan & Cribb, 2006, P. littlewoodi Nolan & Cribb, 2006, and P. munozae Nolan & Cribb, 2006 are each re-reported from their type-host and type-localities. New cox1 mtDNA data were generated for all known species of these two genera from new and archival material. Analyses of these data enabled an evaluation of all known Phthinomita species; P. robertsthomsoni Nolan & Cribb, 2006 is synonymised with P. adlardi Nolan & Cribb, 2006, and P. brooksi Nolan & Cribb, 2006 is synonymised with P. sasali Nolan & Cribb, 2006. We highlight the failure of ITS2 data to delineate closely related aporocotylid species. In contrast, cox1 sequence data are proving reliable and effective in this context and we recommend their incorporation in future studies of blood fluke taxonomy.

  相似文献   

15.
This revision addresses two Southern Hemisphere genera in the family Buccinidae. Buccipagoda kengrahami (Ponder, 1982) and B. ponderi n. sp. are recognised from off southern Australia and B. achilles n. sp. from off New Zealand. Sagenotriton n. gen. is introduced for S. ajax n. sp. from off New Zealand, and S. bathybius (Bouchet & Warén, 1986) and S. bonaespei (Barnard, 1963) from off South Africa.  相似文献   

16.
Traditional studies suggest that the Kallymeniaceae can be divided into two major groups, a nonprocarpic Kallymenia group, in which carposporophyte formation involves an auxiliary cell branch system separate from the carpogonial branch system, and a procarpic Callophyllis group, in which the carpogonial branch system gives rise to the carposporophyte directly after fertilization. Based on our phylogenetic studies and unpublished observations, the two groups each contain both procarpic and nonprocarpic genera. Here, we describe a new method of reproductive development in Callophyllis concepcionensis Arakaki, Alveal et Ramírez from Chile. The carpogonial branch system consists of a supporting cell bearing both a three‐celled carpogonial branch with trichogyne and two‐lobed “subsidiary” cells. After fertilization, large numbers of secondary subcortical and medullary cells are produced. Lobes of the carpogonial branch system cut off connecting cells containing enlarged, presumably diploid nuclei that fuse with these secondary vegetative cells and deposit their nuclei. Derivative enlarged nuclei are transferred from one vegetative cell to another, which ultimately cut off gonimoblast initials that form filaments that surround the central primary medullary cells and produce carposporangia. The repeated involvement of vegetative cells in gonimoblast formation is a new observation, not only in Callophyllis, but in red algae generally. These results call for a revised classification of the Kallymeniaceae based on new morphological and molecular studies.  相似文献   

17.
Three new genera of trypanorhynch cestodes from Australian elasmobranch fishes collected in the Arafura Sea, off the Northern Territory, are described. Fossobothrium perplexum n. g., n. sp. (Otobothriidae), from the spiral valves of Anoxypristis cuspidata (Latham) and Pristis zijsron Bleeker, is similar to the otobothriid genera Pseudotobothrium Dollfus, 1942 and Poecilancistrium Dollfus, 1929 in possessing bothrial pits and a band of hooks on the tentacle, but differs from all known otobothriid genera in having the pits joined by a prominent velum. Iobothrium elegans n. g., n. sp. (Otobothriidae), from the spiral valve of Himantura jenkinsi (Annandale), is placed in the Otobothriidae because it possesses bothrial pits, but differs from Otobothrium Linton, 1890 and other genera in lacking intercalary hooks between the principal rows and in possessing a chainette on the external surface of the tentacle in the metabasal region. Oncomegoides celatus n. g., n. sp. (Eutetrarhynchidae), from the spiral valve of Dasyatis microps (Annandale) and Himantura jenkinsi, resembles Oncomegas Dollfus, 1929 in possessing two bothria and a megahook on the bothrial surface of the basal armature, but differs in possessing an extra row consisting of four intercalary hooks formed by the overlapping of two intercalary hooks on the external tentacular surface between each of the opposing principal rows and is therefore an atypical heteroacanth.  相似文献   

18.
Synaptobothrioides sardinellae n. g., n. sp. is described from Sardinella melanura off Fiji. The new genus differs from other plerurine hemiurid genera in having entire or angular, rather than lobed to digitiform, vitelline masses. It appears closest to Synaptobothrium, but differs in the lack of a presomatic pit and the presence of tegumental plications. Lecithochirium kawakawa from Euthynnus affinis and Thulinia microrchis from Siganus spinus are reported from off Fiji.  相似文献   

19.
Baudinella Thiele, 1931, Retroterra Solem, 1985 and Molema Köhler, 2011 are three genera of camaenid land snail endemic to coastal regions of the Western Australian Kimberley. Each of these genera has fairly distinct shells, but all exhibit a rather similar configuration of the reproductive system, which is characterized by lack of a penial sheath and presence of an elongated and coiled bursa copulatrix. By combining comparative morphology of shell and penial anatomy with analyses of the mitochondrial DNA fragments 16S rRNA (16S) and cytochrome c oxidase subunit 1 (COI), the phylogenetic relationships amongst representative species of these genera are addressed to test the monophyly of taxa and to identify new species. Our results show that all three genera are members of a single camaenid radiation. Five new species are described: two new species of Baudinella, B. magna n. sp. from the Institute and Montesquieu Archipelagos and B. margaritata n. sp. from Pitta Gorge in the Prince Regent Reserve, one new species of Molema, Molema tenuicostata n. sp., from near Talbot Bay, and two new species of Retroterra, R. dichroma, and R. nana, from the Prince Regent Reserve.  相似文献   

20.
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