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1.

A new species of grunt sculpin, Rhamphocottus nagaakii inhabiting the northwestern Pacific, previously identified as Rhamphocottus richardsonii Günther 1874, is described based on genetic evidence and morphological differences. The new species can be distinguished based on morphometric characters related to the head, including head length [45.3–54.6% of standard length (SL)], postorbital head length (18.8–25.5% SL) and the length of pectoral-fin base (15.8–20.7% SL), which are smaller than in R. richardsonii (53.6–60.5% SL, 26.2–31.7% SL, and 19.5–25.2% SL, respectively). Genetic differences between two species markedly exceed levels for intra-specific differences. Rhamphocottus nagaakii is considered to have arisen from a common ancestor of the two species, which probably inhabited somewhere the North Pacific Rim around the Aleutian Archipelago. During a period of cooling in the Pliocene or the Miocene, R. nagaakii and R. richardsonii became separated to the southern regions of the northwestern and northeastern Pacific, and subsequently underwent speciation.

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2.
3.
Faberia Hemsl., a small genus of six species in the tribe Cichorieae, Asteraceae, has been karyologically investigated for the first time. All four studied species were revealed to have the somatic chromosome number 2n = 34, and thus the basic number of the genus was assumed to be x = 17. This rather high basic number has been previously reported very rarely in the tribe, occurring otherwise only in Warionia Benth. & Coss., a monospecific genus endemic to northwestern Africa, and in the American species of Lactuca L. The chromosome morphology was very similar among the four species, with the majority being median centromeric (m) and a few submedian centromeric (sm). In all the karyotypes the chromosomes were medium‐sized (6.33–1.61 μm), and showed a steady gradation in length from the longest to the shortest, with no evidence of bimodality. Our results strongly support the recognition of Faberia as an independent genus and the inclusion of Faberiopsis Shih & Y. L. Chen in Faberia.  相似文献   

4.
Park  Taisoo 《Hydrobiologia》1994,(1):317-332
The geographic distribution of the bathypelagic calanoid genus Paraeuchaeta was investigated by examining midwater trawl and plankton net samples collected mostly from depths exceeding 1000 m throughout the world's oceans. Of the 81 species referred to Paraeuchaeta, the geographic ranges of about 50 species could be defined with reasonable certainty. Contrary to early authors, the number of species having a worldwide distribution was surprisingly small (12 species or 15% of the 81 species of the genus) as compared to common species endemic to various geographic regions (34 species or 42% of the total of 81). Almost twice as many species were found in the Indo-Pacific Ocean as in either the Atlantic or the Southern Ocean. Faunistically, the northern Atlantic, mid-Atlantic, northern Pacific, East Pacific, Indo-West Pacific, and Southern Ocean were distinct in terms of endemic species. A number of species were found to be endemic to highly productive areas, where they were usually very abundant. Rare species, on the other hand, were generally found to be widely distributed, although some were too rare for their range to be determined with certainty. To explain these findings, the following hypothesis is proposed: Bathypelagic calanoids endemic to and abundant in eutrophic areas are those adapted to eutrophic conditions of their habitats and therefore cannot expand their ranges into contiguous oligotrophic waters even if the other environmental conditions are favorable. Other species, on the other hand, generally have extensive geographic ranges because of their survival ability in widely expanding oligotrophic conditions and the absence of physicochemical barriers at bathypelagic depths of the world's oceans.  相似文献   

5.
Aim To investigate phylogeographic relationships, genetic connectivity and potential colonization routes for Hawaii’s endemic butterflyfishes (family Chaetodontidae). Location The Hawaiian Archipelago (central Pacific Ocean). Methods Molecular genetic analysis of mitochondrial DNA from three species of endemic Hawaiian butterflyfishes (Chaetodon multicinctus, n = 280; Chaetodon miliaris, n = 408; Chaetodon fremblii, n = 358) sampled from across the Hawaiian Archipelago was used in a suite of population genetic analyses to examine population histories and calculate coalescence times. We review a recent phylogenetic hypothesis for the Chaetodontidae and optimize ancestral distributions to nodes as a means of inferring colonization pathways to Hawaii. Results We found no evidence for population subdivisions across their ranges for any of the three endemic Hawaiian butterflyfish species (ΦST ≈ 0; P > 0.05 in each case). Coalescence analyses revealed that C. multicinctus, C. miliaris and C. fremblii date to genetic bottlenecks of c. 12 ka (95% confidence interval of τ, 0–46,732 years ago), c. 74 ka (95% confidence interval of τ, 62,918–105,699 years ago) and c. 301 ka (95% confidence interval of τ, 88,981–478,495 years ago), respectively. We found that the West Pacific appears to be the ancestral source for two of three independent colonization events to Hawaii (leading to the speciation of C. miliaris and C. fremblii). The third colonization of Hawaii (leading to the divergence of C. multicinctus) is ambiguous, but may have involved island‐hopping from the South Pacific via the Line Islands. Main conclusions Our results are consistent with the growing body of data indicating that ecological specialists may be more susceptible to severe population bottlenecks during large‐scale climatic variation on evolutionary time‐scales. The isolation of the Hawaiian Archipelago presents challenges for colonization by even the most highly dispersive marine organisms, and routes of colonization by endemic butterflyfishes show a variable pattern, indicating that there may be several pathways, both spatially and temporally, for marine fauna to colonize Hawaii. Hawaiian endemic butterflyfishes appear to represent genetically homogeneous populations across the archipelago.  相似文献   

6.
Most of the known food webs are based on organic compounds provided by photoautotrophic organisms. The terrestrial ecosystem of Malpelo Island (Colombia) seems to be an exception, however, since it supports several trophic guilds without hosting an adequate amount of primary producers. It has been suggested that this apparent paradox might be explained by external inputs provided by seabirds, namely Nazca Boobies (Sula granti), forming a huge colony on Malpelo. This hypothesis has never been tested. Here, we present a first approach to quantify the significance of Nazca Booby inputs into the Malpelo ecosystem via excrement, second eggs/chicks (which are prone to die), and carcasses, respectively, during the major breeding season. The total input was calculated to amount to 171.6 t per breeding season, with excrements accounting for almost 99% (170 t) of this input. Second eggs/chicks contributed approximately 1.1 t (0.64%) and carcasses around 0.1 t (0.06%). These finding support the idea of the Nazca Booby facilitating a food chain that pairs the pelagic primary producers of the open ocean with the terrestrial consumers of an island. Species most strongly profiting from this process include three endemic lizard species (Anolis agassizi, Diploglossus millepunctatus, Phyllodactylus transversalis) and the land crab (Johngarthia malpilensis).  相似文献   

7.
The monotypic genus Tanganikallabes, endemic to Lake Tanganyika, is a poorly known member of the family Clariidae. Examination of 142 specimens housed in museum collections has revealed the presence of at least two additional species in this genus. Tanganikallabes alboperca sp. nov. is distinguished from all congeners by the length of its pelvic fins, the presence of a depigmented vertical bar on the opercular margin, and a combination of additional morphometric (pectoral spine length, preanal length, body depth at anus) and meristic (dorsal and anal fin ray counts) characters. Tanganikallabes stewarti sp. nov. is distinguished from other Tanganikallabes species by having a relatively shorter, incomplete lateral line, and shallow body depth at the anus, as well as shorter prepelvic and preanal lengths, and a longer anal fin with a higher number of fin rays. Several morphological characters, as well as genetic data from cytochrome b (mitochondrial DNA) and 18SITS15.8SITS228S (ribosomal DNA), indicate that Tanganikallabes constitutes a monophyletic group within the Clariidae and support the recognition of additional species diversity. The monophyly of Tanganikallabes, coupled with the geographical isolation of this group to a single lake satisfy the requirements for its classification as a true species flock, the latest to be described from Lake Tanganyika. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 121–142.  相似文献   

8.
Length–weight (LWR) and length–length (LLR) relationships were estimated for four shad species of the genus Alosa, reported from along the southern Caspian Sea coast, north of Iran in a study from March 2014. Two of these species are endemic to the Caspian Sea. The length–weight parameter b for these species ranged from 2.99 to 3.24, with regression coefficients (r2) ranging from 0.91 to 0.99. All LLRs were highly significant (r2 > 0.96).  相似文献   

9.
In this study, a new species of Pseudogilbia Møller, Schwarzhans & Nielsen 2004 is described based on two male specimens (40–44 mm LS) from shallow reefs of Bahia, Brazil. Pseudogilbia australis sp. nov. is distinguished from its only congener, Pseudogilbia sanblasensis Møller, Schwarzhans & Nielsen 2004 from Caribbean Panama, by having: two lower preopercular pores (vs. one); dorsal-fin rays 65–67 (vs. 69); anal-fin rays 51–53 (vs. 56); pectoral-fin rays 18 (vs. 20); caudal vertebrae 27–28 (vs. 30); pectoral-fin length 15.0%–15.9% LS (vs. 14.3); pelvic-fin length 13.5% LS (vs. 16.4) and a different morphology of the male copulatory organ. Pseudogilbia australis sp. nov. is the only dinematichthyid so far recorded in the South Atlantic. An updated diagnosis for the genus is also provided.  相似文献   

10.
ABSTRACT

The species of Satsuma are mostly endemic to East Asia except for one species distributed in Batan Island of the Philippines. More than 99% of the known species of this genus are endemic to the island environment. Only three species are currently known to occur on the mainland. Here we describe a new sinistral Satsuma species from China, Satsuma guandi n. sp. We studied the shell morphology and genital anatomy of the new species and reconstructed the molecular phylogeny of the genus based on partial nucleotide sequences of the mitochondrial gene cytochrome c oxidase subunit I and nuclear markers from the ribosomal RNA cistrons (the internal transcribed spacer and the external transcribed spacer regions). The new species differs from other sinistral Satsuma species by having a strongly angulated shell and an open dark brownish-red umbilicus. The new species also differed from all other sinistral congeners in details of its reproductive anatomy. The molecular analysis supports the validity of the new species within the genus Satsuma.  相似文献   

11.
Malpelo Island is the largest marine protected area (MPA) in the Colombian Pacific; however, the lack of information regarding its ecological dynamics suggests that management and conservation strategies are developed from an individual approach (species or groups of species) and not from an ecosystem one. This study analyzes the terrestrial food web of Malpelo Island, Colombia, based on topological analysis (e.g., centrality). The food web was constructed from 27 nodes representing the main trophogroups, which consist of species or functional groups. Malpelo Island had a food web of four steps with a maximum separation among all trophogroups and trophic pathways, with two steps in average length. Furthermore, the food web was divided into three food web compartments, with a recurrence of connectivity patterns dominated by apparent and exploitative competition, followed by tri-trophic chains and omnivory. Five key trophogroups control the energy flow throughout the food web (detritus, the land crab Johngarthia malpilensis, the lizard Anolis agassizi, the Malpelo dotted galliwasp Diploglossus millepunctatus, and the Nazca booby Sula granti). The high importance of detritus suggests that bottom-up processes act as a control and regulation mechanism of trophic flows. The low number of food web compartments and a high recurrence of specific connectivity patterns in the Malpelo Island terrestrial ecosystem evidence different ecological processes centered on five trophogroups, allowing stability against disturbances. In addition, the simulation of trophogroup removal (randomly or directed) suggests that food web can be vulnerable to structural alterations in their properties, which may have consequences on the resilience of this ecosystem. This study contributes to the knowledge of the trophic dynamics of Malpelo Island, providing a potential tool for management and conservation measures from an ecosystemic approach.  相似文献   

12.
A new species of Dysalotus (family Chiasmodontidae) known only from off the Hawaiian archipelago is described here as Dysalotus pouliulii sp. nov. It differs from all other species of Dysalotus in having a greater number of teeth on the premaxilla (151–198 v. 60–138) and dentary (136–199 v. 76–132) and in a shorter upper jaw [51·9–54·9% of head length (LH) v. 62·4–74·4% LH] and lower jaw (64·8–67·4% in LH v. 75·3–88·1% in LH). A key for the species of Dysalotus and an updated distribution map are provided. http://zoobank.org/urn:lsid:zoobank.org:pub:E9B5F1DC‐52E0‐4F53‐9109‐2A8E252AE8CE .  相似文献   

13.
A new species of pipefish Leptonotus vincentae sp. nov. (Syngnathidae) is described on the basis of 12 specimens found in shallow waters (<2 m depth) of San Antonio Bay, Patagonia, Argentina, in the south-west Atlantic Ocean. The species is distinguished from congeners by the combination of: dorsal-fin rays 30–33, pectoral-fin rays 12–13, trunk rings 18–19, tail rings 43–46, subdorsal rings (2–4) + (5.5–8) = (8.5–10), head length 13–14% standard length, snout length 35–55% head length and snout depth 21–30% in snout length. Although this species has often been mistaken for Leptonotus blainvilleanus, most diagnostic characters of the two species differ. Both species are clearly distinguished by their snout length. L. blainvilleanus has a relatively longer snout than L. vincentae sp. nov. The new species is similar to a south-west Pacific species, Leptonotus elevatus. However, L. vincentae sp. nov. differs from this species in that it exhibits a lower number of dorsal-fin rays and a relatively longer head.  相似文献   

14.
Episodes of trans-Arctic faunal exchange and isolation between the north Pacific and Atlantic ocean basins have been implicated as important historic geological events contributing to extant patterns of genetic diversity and structure in Holarctic faunas. We made a further test of the significance of such biogeographic events by examining mitochondrial DNA (mtDNA) restriction fragment length and cytochrome b sequence polymorphism among north Pacific and Arctic, north-western Atlantic (north-eastern North American), and north-eastern Atlantic (European) regional forms of the boreal smelt, genus Osmerus. Our analyses also assessed whether the regional forms within this ‘species complex’: (i) represent a single widely distributed and polytypic species, or is composed of three geographically distinct species, and (ii) resulted from a single split from north Pacific ancestral Osmerus or two independent Pacific-Atlantic divergences. MtDNA sequence divergence estimates among forms ranged from 5.6–8.9% and from 6.1–8.5% based on restriction fragment and 300 base pairs of cytochrome b sequencing, respectively. Divergence within forms averaged less than 0.5% for fragment analysis and no differences were detected from sequence analysis. Provisional dating of lineage separations in Osmerus based on our sequence divergence estimates suggested a mid-Pliocene to early Pleistocene time frame for diversification among the forms. These estimated lineage separation dates support the idea that geological events in ‘Beringia’ and the surrounding trans-Arctic area (e.g. opening of the Bering Seaway, Pleistocene glacial advances), occurring over a similar time frame, have influenced radiation in Osmerus. Phenetic and parsimony analyses of the sequence divergence estimates and of sequence polymorphisms suggested that the north Pacific/Arctic form and the northwestern Atlantic form shared a common ancestor more recently than either has with the north-eastern Atlantic form, thus supporting the hypothesis that the species complex has arisen from two independent Pacific-Atlantic divergences probably beginning during the mid-Pliocene.  相似文献   

15.
Aim We analysed the distribution patterns of the eastern Pacific octocoral genus Pacifigorgia and deduced its ancestral distribution to determine why Pacifigorgia is absent from the Gulf of Mexico, the Caribbean of central America, and the Antilles. We also examined the current patterns of endemism for Pacifigorgia to look for congruence between hot spots of endemism in the genus and generally recognized areas of endemism for the eastern Pacific. Location The tropical eastern Pacific and western Atlantic, America. Methods We used track compatibility analysis (TCA) and parsimony analysis of endemicity (PAE) to derive ancestral distribution patterns and hot spots of endemism, respectively. Distributional data for Pacifigorgia were gathered from several museum collections and from fieldwork, particularly in the Pacific of Costa Rica and Panama. Results A single generalized track joined the three main continental eastern Pacific biogeographical provinces and the western Atlantic. This track can be included within a larger eastern Atlantic–eastern Pacific transoceanic track that may be the oldest transoceanic track occurring in the region. PAE results designate previously recognized eastern Pacific biogeographical provinces as Pacifigorgia hot spots of endemism. The number of endemic species, which for other taxonomic groups is similar among the eastern Pacific provinces, is higher in the Panamic province for Pacifigorgia. Main conclusions We propose that the absence of Pacifigorgia from the Gulf of Mexico, the Caribbean of central America, and the Antilles is the result of an ancient absence of the genus from these areas rather than the consequence of a major, recent, extinction episode. The Cortez province and the Mexican province appear together as a result of either non‐response to vicariance or dispersal across the Sinaloan Gap. We posit that the Central American Gap acts as a barrier that separates the Panamic province from the northern Cortez–Mexican province.  相似文献   

16.
Length–weight (LWR) and length–length (LLR) relationships were estimated for 330 specimens from nine Paracobitis species in 11 localities throughout Iran. All fish were collected upon occasion by electrofishing throughout Iran from July 2010 to October 2016. These represent the first reports of LWR data for eight species including: Paracobitis atrakensis, P. hircanica, P. longicauda, P. molavii, P. persa, P. rhadinaeus, P. smithi and P. vignai and first LLR data for all species. A new maximum length is reported for P. malapterura. Four of these species are endemic and five species are native to Iran. The length–weight parameter b ranged from a minimum of 2.74 for P. atrakensis to a maximum of 3.01 for P. longicauda, with regression coefficients (r2) ranging from 0.96 to 0.99. All LLRs were highly significant (r2 > .96).  相似文献   

17.
A taxonomic review of the clingfish genus Kopua (Gobiesocidae: Trachelochisminae) in Japan recognizes three species: K. japonica Moore, Hutchins and Okamoto 2012, K. vermiculata Shinohara and Katayama 2015 and K. yoko sp. nov. Kopua japonica and K. vermiculata are redescribed with revised diagnoses on the basis of 20 specimens (10.4–30.4 mm standard length; SL) and the holotype, respectively. Kopua japonica is similar to K. vermiculata in head sensory pore characters (normally single nasal and postocular canal pores). However, the former differs distinctly from the latter as follows: 6–8 (modally 7) gill rakers (vs. 4 or 6); 31–33 (33) vertebrae (vs. 35); anus slightly closer to posterior margin of disc than to anal-fin origin (vs. much closer to posterior margin of disc); snout length 5.3–8.7 (mean 7.0) % SL (vs. 9.2 % SL); disc length 21.2–24.0 (22.8) % SL (vs. 18.8 % SL); pre-dorsal- and anal-fin lengths 72.9–78.4 (75.2) and 78.1–82.8 (80.1) % SL, respectively (vs. 67.5 and 73.6 % SL); and two stripes on cheek (vs. a triangular blotch). Kopua yoko sp. nov., based on 14 specimens (17.7–28.8 mm SL) from the Pacific coast of southern Japan, Sea of Japan and the East China Sea, is characterized by the following combination of characters: 6 or 7 (modally 6) dorsal-fin rays; 4–6 (5) anal-fin rays; 21 or 22 (21) pectoral-fin rays; 4–6 (5 or 6) gill rakers; 31–33 (31) vertebrae; a single (rarely two) nasal canal pores; two lacrimal and preopercular canal pores; snout length 6.5–7.9 (mean 7.1) % SL; gill opening depth 5.8–7.1 (6.5) % SL; least interorbital width 2.0–3.7 (2.6) % SL; disc length 20.3–25.0 (23.1) % SL, disc region D without flattened papillae; caudal-peduncle depth 8.1–10.2 (9.2) % SL; anus slightly closer to posterior margin of disc than to anal-fin origin; pre-dorsal- and anal-fin lengths 71.6–77.1 (73.9) and 77.0–83.7 (80.4) % SL, respectively; post-dorsal-caudal length 12.6–15.0 (13.8) % SL; arch-shaped blotches on lateral aspect of body; and two reddish-orange stripes on cheek. Morphological changes with growth in K. japonica and K. yoko sp. nov. are also described.  相似文献   

18.
We surveyed the dinoflagellate genus Prorocentrum Ehrenberg in Mexican Pacific waters, where it is rather common and sometimes causes red tides in coastal areas or shrimp farms. Material collected from Baja California and the Gulf of California was analyzed. Thirteen species were identified, all of them planktonic (although P. mexicanum is also epiphytic). All species are described by light microscopy, and most are also described by scanning electron microscopy; comments on morphology, taxonomy and distribution are made. Red tides were caused by P. dentatum, P. minimum and P. triestinum. Prorocentrum mexicanum and P. minimum were suspected of being toxic. Four species, previously reported in the Gulf of California, were not found. A total of 18 species, including the new records P. dactylum and P. lebourae have been to date reported from the Mexican Pacific.  相似文献   

19.
The four species included in the family Cryptacanthodidae are eel‐like, burrowing fishes distributed in the cold‐temperate coastal waters of the North Pacific and the western North Atlantic. This study describes the osteology and aspects of the ontogenetic skeletal development of two species, Cryptacanthodes maculatus from the western North Atlantic and C. aleutensis from the eastern North Pacific. We discuss the relationships of Cryptacanthodidae among other zoarcoid families. The Cryptacanthodidae have been previously included in the Stichaeidae, but removed and classified as a separate family based on the skull, pectoral radial, and cephalic lateral‐line morphology. Our observations (similarities in gill arch and pectoral girdle morphology; specifically, a thin sheet‐like flange of bone from the posterior margin of the supracleithrum) suggest a close relationship to at least some of the members of the family Stichaeidae. J. Morphol. 276:185–208, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   

20.
ABSTRACT

Encrasicholina auster sp. nov. (Clupeiformes: Engraulidae) is described on the basis of six specimens collected from Fiji, southwestern Pacific Ocean. The new species is distinguished from congeners by the following combination of characters: long upper jaw (posterior tip extending beyond posterior margin of preopercle) 20.8%–22.5% standard length (SL); long lower jaw 19.0%–20.7% SL; long head 29.1%–29.2% SL; three unbranched rays in the dorsal and anal fins; transverse scales 11; branched pectoral-fin rays 12–13; pseudobranchial filaments 19–21; gill rakers 45–49, 40–43, 26–31 and 22–25 on the first, second, third and fourth gill arches, respectively.  相似文献   

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