Bathyconchoecilla, a new genus of deep plankto-benthic halocyprids (Ostracoda, Myodocopa) from the northern Pacific and an overview of Bathyconchoeciinae

Crustaceana ◽  
2018 ◽  
Vol 91 (11) ◽  
pp. 1291-1317
Author(s):  
Vladimir G. Chavtur ◽  
Alexander G. Bashmanov

Abstract Plankto-benthic ostracods of the subfamily Bathyconchoeciinae constitute an extremely heterogeneous group of species, as well in body size, as well as in the shape and structure of carapace and limbs. At present, their fauna contains 35 known (described) species, belonging to four genera. Besides that, about 50 species with still open nomenclature were noted in the literature and have been found in material from our collections. A preliminary morphological analysis of the bathyconchoeciines allowed, in addition, to single out 13 species complexes (= putative genera). One of these genera is described herein as Bathyconchoecilla gen. nov., from the deep-sea zone of the Kurile-Kamchatka Trench. The new genus differs from other genera in this subfamily by the shape and sculpture of the carapace, the location of the left hook on the second antenna in the male, and the structure of the coxale and basale of the mandible and the endites of the maxilla.

2007 ◽  
Vol 145 (1) ◽  
pp. 73-84 ◽  
Author(s):  
GIORGIO CARNEVALE

AbstractA new genus and species of deep-sea hatchetfish, Discosternon federicae gen. et sp. nov., is described from the Middle Miocene (Serravallian) calciturbititic deposits of the Tufillo Unit exposed near the town of Gessopalena, central Italy. It is based on a single, very small, well-preserved and nearly complete specimen that exhibits a discoid physiognomy and a unique combination of features, many of which are reductive (loss of dorsal blade, loss of anal-fin hiatus, loss of abdominal keel-like structure, reduction of number of supraneurals, reduction of number of caudal vertebrae, presence of slender neural and haemal spines, external surface of cleithrum smooth). The comparative morphological analysis indicates that Discosternon is probably related to the derived genera Horbatshia and Sternoptyx. The highly reduced body size and the possession of many reductive characters indicate that Discosternon can be presumed to be a miniature fish. Anatomical and morphofunctional considerations suggest that Discosternon possibly was a midwater plankton feeder characterized by a reduced locomotory ability.


Author(s):  
Marie L Verheye ◽  
Cédric D’Udekem D’Acoz

Abstract Among Antarctic amphipods of the genus Eusirus, a highly distinctive clade of giant species is characterized by a dorsal, blade-shaped tooth on pereionites 5–7 and pleonites 1–3. This lineage, herein named ‘crested Eusirus’, includes two potential species complexes, the Eusirus perdentatus and Eusirus giganteus complexes, in addition to the more distinctive Eusirus propeperdentatus. Molecular phylogenies and statistical parsimony networks (COI, CytB and ITS2) of crested Eusirus are herein reconstructed. This study aims to formally revise species diversity within crested Eusirus by applying several species delimitation methods (Bayesian implementation of the Poisson tree processes model, general mixed Yule coalescent, multi-rate Poisson tree processes and automatic barcode gap discovery) on the resulting phylogenies. In addition, results from the DNA-based methods are benchmarked against a detailed morphological analysis of all available specimens of the E. perdentatus complex. Our results indicate that species diversity of crested Eusirus is underestimated. Overall, DNA-based methods suggest that the E. perdentatus complex is composed of three putative species and that the E. giganteus complex includes four or five putative species. The morphological analysis of available specimens from the E. perdentatus complex corroborates molecular results by identifying two differentiable species, the genuine E. perdentatus and a new species, herein described as Eusirus pontomedon sp. nov.


2005 ◽  
Vol 297 ◽  
pp. 181-187 ◽  
Author(s):  
CR McClain ◽  
MA Rex ◽  
R Jabbour
Keyword(s):  

Zootaxa ◽  
2021 ◽  
Vol 5051 (1) ◽  
pp. 117-150
Author(s):  
SAMUEL GÓMEZ ◽  
JOSÉ ANTONIO CRUZ-BARRAZA

At present, only 11 species of harpacticoid copepods have been described from the deep sea of the Gulf of California and the west coast of the Baja California Peninsula. These efforts had until recently been focused exclusively on the families Ameiridae Boeck, Argestidae Por, and Rhizothrichidae Por. Preliminary analyses revealed also an important contribution of the subfamily Stenheliinae Brady (Miraciidae Dana) to the overall species richness and diversity of deep-sea benthic copepods from the west coast of the Baja California Peninsula, and the central and southern Gulf of California. One new species of the genus Wellstenhelia Karanovic & Kim, 2014, We. euterpoides sp. nov., and one new genus and species, Wellstenvalia wellsi gen. et sp. nov., are herein described from sediment samples taken at eight sampling stations in the west coast of the Baja California Peninsula and in the central and southern Gulf of California. Wellstenhelia euterpoides sp. nov. seems to be closely related to We. euterpe Karanovic & Kim, 2014 with which it shares the reduced armature complement of the baseoendopod of the female fifth leg. The so far monotypic genus Wellstenvalia gen. nov. was found to be closely related to Muohuysia Özdikmen, 2009 and Wellstenhelia. Some comments on the relationships between the new genus proposed here and other stenheliin genera and species are provided as a contribution towards the monophyly of the subfamily.  


2003 ◽  
Vol 77 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Martin J. Head ◽  
Geoffrey Norris

Detailed investigation of the essentially complete uppermost Miocene through Lower Pleistocene sequence in Deep Sea Drilling Project (DSDP) Hole 603C, western North Atlantic, has revealed the presence of the new dinoflagellate cyst speciesLejeunecysta hatterasensis, Lejeunecysta interrupta, Corrudinium devernaliae, andPyxidinopsis vesiculata, as well as the acritarchsLeiosphaeridia rockhallensisHead new species andLeffingwellia costatanew genus and species. Independent magnetobiostratigraphic control of DSDP Hole 603C constrains the ranges of these new species.Lejeunecysta interruptan. sp. appears to range no higher than lowermost Pliocene at 5.2 Ma,Pyxidinopsis vesiculatan. sp. has a range top at about 4.5 Ma in the Lower Pliocene,Corrudinium devernaliaen. sp. has a well-defined range of 4.7–4.1 Ma within the Lower Pliocene, andLeiosphaeridia rockhallensisn. sp. has a similarly well-defined range of 4.4–3.9 Ma within the Lower Pliocene. The presence ofLeiosphaeridia rockhallensisn. sp. in the Ramsholt Member of the Coralline Crag Formation, eastern England, supports an Early Pliocene age for this member.


Zootaxa ◽  
2007 ◽  
Vol 1430 (1) ◽  
pp. 1-86 ◽  
Author(s):  
E. NICHOLAS ARNOLD ◽  
OSCAR ARRIBAS ◽  
SALVADOR CARRANZA

DNA sequence indicates the Lacertidae contain two subfamilies, Gallotiinae and Lacertinae, the latter comprising two monophyletic tribes, the Eremiadini of Africa and arid southwest and central Asia, and the Lacertini of Europe, northwest Africa and southwest and east Asia. Relationships within the 108 species of Lacertini are explored using mtDNA (291 bp cytochrome b; 329 bp 12S rRNA for 59 nominal species, and reanalysis of the data of Harris et al. 1998, and Fu 2000). The morphology of the tribe is reviewed and 64 of its characters (equivalent to 83 binary ones) also used to assess relationships. The Lacertini are assigned to 19 monophyletic units of 1 to 27 species, recognised here as the following genera (contents are indicated in brackets): Algyroides, Anatololacerta gen. nov. (L. danfordi group), Apathya (L. cappadocica group), Archaeolacerta (L. bedriagae), Dalmatolacerta gen. nov. (L. oxycephala), Darevskia (L. saxicola group), Dinarolacerta gen. nov. (L. mosorensis), Hellenolacerta gen. nov. (L. graeca), Iberolacerta (L. monticola group), Iranolacerta gen. nov. (L. brandtii and L. zagrosica), Lacerta s. str. (sand and green lizards, L. agilis group), Parvilacerta gen. nov. (L. parva and L. fraasii), Phoenicolacerta gen. nov. (L. laevis group), Podarcis (wall lizards), Scelarcis (L. perspicillata), Takydromus (Asian grass lizards), Teira (L. dugesii), Timon (ocellated lizards, L. lepida group) and Zootoca (L. vivipara). Both mtDNA and morphology indicate that Lacerta and Timon are sister taxa, and DNA suggests further possible relationships among genera (Fig. 1, p. 6). Neither DNA nor morphology indicates that the archaeolacertas (sometimes formalised as Archaeolacerta sens. lat.) form a clade. Instead, they are representatives of an ecomorph associated with living on rock exposures and using the narrow crevices that these contain. The Lacertidae probably arose in the European area, with the Gallotiinae later reaching Northwest Africa and the Canary Islands, and the ancestor of the Eremiadini invading Africa in the mid-Miocene. The Lacertini spread through much of their present European range and diversified, perhaps largely by repeated vicariance, around 12–16 My ago, producing the ancestors of the present mainly small-bodied genera, which then underwent often modest speciation. Three units spread more widely: the Lacerta-Timon clade of large-bodied lizards probably dispersed earliest, followed by Algyroides and then Podarcis. Overall, European Lacertidae show a pattern of repeated spread, often accompanied by restriction of previous groups. Expansion of Lacertini may have displaced earlier lacertid lineages from all or much of Europe; while spread of Podarcis may have restricted many other genera of Lacertini. The earlier expansion of the Lacerta-Timon clade probably did not have this effect, as difference in adult body size restricted competitive interaction with other forms. Several invasions of more distant areas also occurred: of East Asia by Takydromus over 10 My ago, and more recently of northwest Africa by Podarcis, Scelarcis and Timon, and Madeira by Teira. Relationships within the Eremiadini estimated from both mtDNA, and nDNA differ considerably from those based on morphology. They indicate relatively mesic forms may have diversified widely across Africa and given rise to at least three independent invasions of arid habitats. MtDNA also indicates that Lacerta andreanskyi belongs in the Eremiadini and may occupy a basal position there. It is assigned to a further new genus, Atlantolacerta gen. nov.


Author(s):  
Janne I. Kaariainen ◽  
Brian J. Bett

The benthic body size miniaturization hypothesis states that deep-sea communities are dominated by organisms of smaller body size, although some field studies have produced contradictory results. Using appropriate sample sets, this study tests this hypothesis by contrasting the benthic communities of the Fladen Ground (North Sea, 150 m) and the Faroe–Shetland Channel (1600 m). Samples were collected for large (500 μm) and small macrofauna (250–355 μm), meiofauna (45 μm) as well as an intermediate sized ‘mesofauna’ (180 μm) to ensure comprehensive coverage of the full meio- and macro-faunal body size-range. The body size structure of the benthos was compared using two methods. The more widely used average individual biomass method involves dividing the total sample biomass by sample abundance. Additionally, body size accumulation curves were constructed by assigning all specimens into a logarithmic size-class and then plotting the cumulative percentage of individuals present in each size-class. The results seem to support the hypothesis that the deep-sea environment is a small organism habitat. Although these findings only represent two locations, the overall body size accumulation curves clearly display a statistically significant shift towards smaller body sizes at the deeper site. The magnitude of the effect is appreciable with median metazoan body size reducing from 14.3 μg wet weight in the Fladen Ground to 3.8 μg wet weight in the Faroe–Shetland Channel. The average individual biomass measurements are shown to be of limited value and can lead to potentially misleading conclusions if the underlying size structure is not analysed in detail.


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