Fishes and environment in northwestern Argentina: from lowland to Puna

The fish fauna and its relationships with physiography and climate were studied in northwestern Argentina from 21°30′ S to 26°30′ S and 63°30′ W to 65°50′ W, an area about 10,276 km². Along a southeast–northwest gradient, the Chaco forest at low altitudes gives way to the Yungas cloud forest in highlands, and then, to an increasing desertic landscape, with xerophytic vegetation and scarce rainfall along the Grande River. Finally, extreme desert conditions prevail in the most northern part at the Puna plateau. Water chemistry was sampled from sites from 400 to over 3800 m a.s.l. In all 3278 fish specimens of 52 species were collected. Previous lists included 84 species. Only 19 were shared, meaning that 40 species are new for the area and/or particular localities, including 7 reports from Aguas Calientes. These results increase by one third the number of species in northwestern Argentina. The fish fauna was represented by eurytopic species of Paranensean genera as Astyanax, Bryconamericus and other characoids, mixed with locally distributed siluriforms. Under extreme climatic conditions, species of Trichomycterus predominate. Species assemblages show a combination of a large number of species typical of, sometimes endemic to or rather abundant in, the area, combined with a few species of Paranensean character. Fish assemblages were clearly defined by faunistic composition and distribution related with physiography and climate traits. A significant negative correlation is observed between both species number and abundance, and increasing altitude, and positive relationships exist with mean annual temperature and other climate traits. Diversity values (Shannon index) agree with the described pattern of increasing impoverishment of the fish fauna of northwestern Argentina, along gradients of increasing altitude and dryness and decreasing temperature.A first version of this paper was submitted at the XXVII Congress of the Societas Internationalis Limnologiae, Dublin, Ireland, 1998.     

Fossil moonseeds from the Paleogene of West Gondwana (Patagonia,Argentina)

Premise of the Study

The fossil record is critical for testing biogeographic hypotheses. Menispermaceae (moonseeds) are a widespread family with a rich fossil record and alternative hypotheses related to their origin and diversification. The family is well‐represented in Cenozoic deposits of the northern hemisphere, but the record in the southern hemisphere is sparse. Filling in the southern record of moonseeds will improve our ability to evaluate alternative biogeographic hypotheses.

Methods

Fossils were collected from the Salamanca (early Paleocene, Danian) and the Huitrera (early Eocene, Ypresian) formations in Chubut Province, Argentina. We photographed them using light microscopy, epifluorescence, and scanning electron microscopy and compared the fossils with similar extant and fossil Menispermaceae using herbarium specimens and published literature.

Key Results

We describe fossil leaves and endocarps attributed to Menispermaceae from Argentinean Patagonia. The leaves are identified to the family, and the endocarps are further identified to the tribe Cissampelideae. The Salamancan endocarp is assigned to the extant genus Stephania. These fossils significantly expand the known range of Menispermaceae in South America, and they include the oldest (ca. 64 Ma) unequivocal evidence of the family worldwide.

Conclusions

Our findings highlight the importance of West Gondwana in the evolution of Menispermaceae during the Paleogene. Currently, the fossil record does not discern between a Laurasian or Gondwanan origin; however, it does demonstrate that Menispermaceae grew well outside the tropics by the early Paleocene. The endocarps’ affinity with Cissampelideae suggests that diversification of the family was well underway by the earliest Paleocene.     

Enigmatic and little known Odonata (Insecta) from the Paleogene of Patagonia and Northwest Argentina

The findings of new specimens of Latibasaliidae and Frengueliidae in Northwest and Patagonia Argentina are noteworthy for the knowledge of these little know families and the explanation of their systematic position. The new findings confirm the phylogenetic position of these families. The morphology of the discoidal cell in both fore and hind wings of Frenguelia corresponds to the most basal epiproctophoran damsel-dragonflies, implying a Triassic age for the particular lineage of this family. The absence of any fossil record between Triassic and Eocene could be related to a highly specialized biology for these animals, maybe related to mountain rainforests as for Epiophlebia, unique surviving damsel-dragonfly. Lastly, the middle Eocene Italian dragonfly family Bolcathemidae Gentilini 2002 is considered as a junior synonym of the Paleocene Argentinean family Palaeomacromiidae Petrulevicius et al. 1999 supporting faunistic contact between Europe and South America during the late Cretaceous.     

Argentina adulterina (Rosaceae‐Potentilleae), a new species from New Guinea

Argentina adulterina Soják sp. nova from New Guinea (Irian Jaya) is described and compared with allied species. Habitually it is similar to A. irianensis, but in leaflet dentation it agrees with A. biloba. Leaves and leaflets of these three species are illustrated and a depiction of calyces of A. adulterina and A. irianensis is presented (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Comparative composition of the snake assemblage from Sierras de Ventania mountain range,east-central Argentina

ABSTRACT

The composition of a snake assemblage from an orographic island in east-central Argentina, the Sierras de Ventania mountain chain, was analyzed. The aim was to determine the biogeographic resemblance to other snake assemblages from neighboring regions. Species composition of each region was obtained from an exhaustive review of the literature, and both fieldwork and museum records. The higher biogeographic resemblance of the Sierras de Ventania occurred with the Sierras de Tandilia and the Coastal Dunes. These regions formed a well-defined group according to their snake assemblages. On the other hand, the Sierras de Lihué Calel linked to the Sierras de Ventania, and also to the rest of the compared regions, at very low values of biogeographic resemblance. The results obtained in this study contrasted with the classic zoogeographic scheme. Snake assemblages allowed recognizing a more significant division between Central and Pampean domains. In this scheme, the limit between these two regions moved to the southwest of the classical scheme; therefore the Sierras de Ventania was part of the Pampean domain. Also, the recognition of the Subtropical domain was evident, as well as its faunistic link with the Pampean domain.     

广西南部地区蚱总科一新属和七新种

记述采自广西南部地区蚱总科一新属七新种,即横刺郑蚱Zhengitettix transpicula sp.nov.,拟奇蚱属Miriatroides gen.nov.,方顶拟奇蚱Miriatroides quadrivertex sp.nov., 长背蟾蚱Hyboella longinota sp.nov.,二瓣庭蚱Hedotettix bivalvatus sp.nov.,防城柯蚱Coptotettix fangchengensis sp.nov.,桂南蚱Tetrix guinanensis sp.nov.,波股悠背蚱Euparatettix sinufemoralis sp.nov。模式标本保存于陕西师范大学动物研究所标本室。     

Reappraisal of the giant caviomorph rodent Phoberomys burmeisteri (Ameghino, 1886) from the late Miocene of northeastern Argentina,and the phylogeny and diversity of Neoepiblemidae

Phoberomys is a giant caviomorph rodent included in the extinct Neoepiblemidae. It is recorded in the late Miocene-Pliocene of South America (Argentina, Venezuela, Brazil and Peru), and is one of the largest rodents that have ever lived. In this contribution we study specimens of Phoberomys from the ‘Mesopotamiense’, late Miocene of Entre Ríos Province (Argentina), including several unpublished specimens and the holotypes of the five nominal species (Ph. burmeisteri, Ph. praecursor, Ph. insolita, Ph. lozanoi and Ph. minima) previously recognised for this unit. Our study indicates that all Mesopotamian specimens belong to Phoberomys burmeisteri, and that the differences among them reveal individual and ontogenetic variation. Our phylogenetic analysis indicates that Neoepiblemidae is monophyletic and includes Phoberomys, Neoepiblema, and Perimys. Phoberomys species are recovered as a clade, which is more closely related to Neoepiblema than to the Patagonian Perimys. In addition, our study shows that Eusigmomys is not a Neoepiblemidae, but a Dinomyidae.     

A new Diacyclops (Copepoda,Cyclopoida, Cyclopidae) from northwestern Argentina

No species of the genus Diacyclops has been so far cited from continental Argentina. Specimens collected from a roadside pool in the province of Catamarca on a plateau at 3700 m a.s.l. turned out to belong to a new species, Diacyclops andinus, which is described and illustrated in detail for both sexes. Main diagnostic features are: spine formula of swimming legs 3, 4, 4, 4; terminal spines of the distal endopod segment of leg 4 subequal; smooth furcal rami. The new species is a member of the D. bicuspidatus group, and is probably near the base of this line.     

Presence of the large aquatic snake Palaeophis africanus in the middle Eocene marine margin of the Congo Basin,Cabinda, Angola

Ten isolated snake vertebrae from Landana and Sassa-Zao, Cabinda Exclave, Angola, present a “primitive” grade morphology with a weak lateral compression and do not belong to Palaeophis aff. typhaeus as originally referred to. They well belong to a single taxon and are here attributed to Palaeophis africanus for which the intracolumnar variation is described and illustrated. This species is Lutetian (middle Eocene) in age and originates from a marine coastal environment confirming again the aquatic capabilities of palaeophiid snakes. It represents the third largest species of Palaeophis with P. colossaeus and P. maghrebianus to which it is closely related in our tentative phylogenetic analysis, indicating that these three taxa could belong to an African clade. This study also contributes to the debate on the existence of primitive and advanced grades among palaeophiid snakes. Palaeophis presents laterally compressed anterior trunk vertebrae that could have been often erroneously considered as representing advanced grade species and potential parataxonomy.     

Structural changes and dynamics of the phytoplankton along a highly polluted lowland river of Argentina

The phytoplankton of the Matanza-Riachuelo river (Buenos Aires, Argentina) was studied for a period of 15 months together with different physical and chemical variables, along an increasingly eutrophic in character downstream. 281 taxa were recorded within a seasonal succession, among these 49 percent were euglenophyta, 25 percent bacillariophyta, 15 percent chlorophyta and 10 percent cyanophyta. Multivariate procedures included cluster analyses and ordination by PCA of both species and samples, and stepwise multiple regression analyses were employed to assess the impact of the pollution on the phytoplankton. The effect of the alteration was different in each studied site. With one exception, the changes in the community structure described herein involved modifications of the basic species composition. According to the species present, it was deduced that the main pollutant was the high concentration of organic matter. Results of the Matanza-Riachuelo, Reconquista, and Luján Rivers studies are further discussed.     

New record of the genus Ithytrichia (Trichoptera: Hydroptilidae) for South America,with descriptions of male,larva and pupa of a new species from northwestern Argentina

Ithytrichia is a small genus of Hydroptilidae, recorded from Europe, North America, and north Central Mexico. The first record of Ithytrichia for South America is presented here. A new species of this genus Ithytrichia ferni is described from northwestern Argentina. Diagnostic characters of the male imago, pupa and larva are described and illustrated. Biological notes are included.     

江苏网翅蝗科一新属一新种(直翅目:蝗总科)

记述了采自江苏泗阳县网翅蝗科1新属——苏蝗属Suacris gen.nov.及1新种——Suacris siyangensis sp.nov..该新属近似于牧草蝗属Omocestus I.Bol.,其主要区别特征为:前胸背板侧隆线微微弯曲,最宽处为最窄处的1.6～1.8倍;前翅肘脉域几乎等宽或略宽于中脉域;鼓膜器雄性宽卵形、雌性狭缝状.该新属也近似于拟草地蝗属Stenobothroides Xu et Zheng,其主要区别特征为:侧隆线明显且弯曲;雄性腹部末节无尾片;雄性下生殖板长锥形.新种模式标本保存于中国科学院西北高原生物研究所.1 苏蝗属,新属Suacris gen.nov. 模式种:泗阳苏蝗Suacris siyangensis sp.nov. 正模:1♂;副模:1♀,江苏泗阳,1957-Ⅸ-16,采集者未知. 体小型.头大而短,较短于前胸背板.头侧窝明显,呈长方形.颜面向后倾斜.中单眼较小于侧单眼.触角丝状,基部触角节宽大于长,向端部触角节渐渐变狭.前胸背板中隆线明显,侧隆线在沟前区微微弯曲,其最宽处约为最窄处的1.6～1.8倍;前胸背板后缘中央钝角形.前、后翅发达,超过后股节中部,前翅顶端圆形,无凹陷,前翅肘脉域几乎等宽或略宽于中脉域.中、后胸腹板侧叶全长均明显地分开.后足股节内侧具发音齿,可与前翅纵脉磨擦发音.后足胫节缺外端刺.鼓膜器:雄性宽卵形,雌性宽缝状.     

Squamate reptiles from the middle Eocene of Lissieu (France). A landmark in the middle Eocene of Europe

In Europe, faunas of squamates (lizards and snakes) from the middle Eocene are very poorly known, with the exception of those from the level MP 16 (latest middle Eocene). From the MP 11-MP 15 interval, squamates were previously reported only from Messel (MP 11, earliest middle Eocene) and from the untere and obere Mittelkohle of Geiseltal (MP 12 and MP 13 respectively) in Germany. The present report describes the middle Eocene assemblage of squamates from Lissieu (France), the first fauna reported from the level MP 14. Whereas fossils from Messel and Geiseltal are mostly articulated skeletons, fossils from Lissieu are represented by disarticulated bones; such fossils may be more easily compared to those from other Cenozoic localities, in which bones are almost always disarticulated. The fauna from Lissieu is more diverse than those from the Geiseltal sites and approximately as diverse as that from Messel as they are presently known; it is comprised of 17 distinct taxa. These taxa cannot be all identified to the species or genus level. They belong to iguanids, gekkonids, lacertids, anguids, thecoglossan platynotans, ophidians incertaesedis, boids, ?tropidophiines, “tropidophiids” incertaesedis, booids incertaesedis, and perhaps russellophiids. The fauna includes several new taxa but only a presumed tropidophiine snake may be named on the basis of the available material. The fauna from Lissieu is a mixture of taxa restricted to the middle Eocene and taxa known from older or younger levels. Taxa shared by Lissieu and the few other localities from the middle Eocene of Europe are rare. This fauna from Lissieu represents a stratigraphical landmark for the middle Eocene.     

Alsodes Australis,A New Species of Leptodactylid Frog from the Temperate Nothofagus Forest of Southern Chile and Argentina

A new species of frog, Alsodes australis, is described from the temperate Nothofagus forest of southern Chile and Argentina, based on adults and tadpoles. Up to now, no sympatric occurrence of another congeneric species is known from the type locality. The genus comprises three species groups. From a karyological point of view this species is included in the monticola group, whose species have 26 chromosomes.     

Saprolegnia oliviae sp. nov. isolated from an Argentine river (Tierra del Fuego Province,Argentina)

Saprolegnia oliviae sp. nov. is described from litter (floating dead twigs, leaves and roots) in the Olivia River, Ushuaia Department, Tierra del Fuego Province (Argentina). The new species is illustrated and compared with other species of the genus. Distinguishing characteristics of S. oliviae are the production of smooth oogonia (with some lateral or terminal projections) and the absence of antheridial branches on the majority of the oogonia, but when present, they are mostly diclinous, at times oogonia are supplied with androgynous and monoclinous antheridial branches. The oogonial stalks are predominantly short and straight or long and bent, curved or many times coiled; oospores are distinctive subcentric, (1-) 15-50 (-70) per oogonium. Morphological details of the new species and its comparison with other described species are discussed here.     

中国逍遥蛛科化石新属种（蜘蛛目，逍遥蛛科）

记述产自中国辽西的逍遥蛛科化石1新属：白垩逍遥蛛属Cretadromus gen．nov．,1新种：辽宁白垩逍遥蛛Cretadromus liaoningensis sp．nov．：这是逍遥蛛科化石在中国的首次发现,也是逍遥蛛科在晚侏罗世-早白垩世的首次报道。标本采白辽宁省凌源市大王杖子晚侏罗世-早白垩世义县组地层,现存于大连自然博物馆：     

Quaternary and recent Lamprothamnium groves (Charophyta) from Argentina

Only recently have extant Lamprothamnium species been reported from the American continent. L. succinctum (A. Br. in Asch.) R. D. W. was found in Lago Titicaca, Bolivia and L. haesseliae Dont. en Laguna Luro and Laguna La Salada, Argentina.Fossil gyrogonites of L. succinctum and L. haesseliae, however, are here reported to be widely distributed in Quaternary sediments of Argentina, associated with other charophytes, ostracods and foraminiferans. Localities include Laguna del Siasgo, Laguna Salada Grande, Laguna Mar Chiquita, Laguna La Amarga and Salina del Bebedero. Lamprothamnium is a genus that prefers shallow, alkaline, hyposaline to mesosaline environments. Analysis of the characteristics of Laguna La Salada contributes information on the factors that influence the distribution of the genus.The morphology characteristics of the gyrogonites and oospores of L. haesseliae and the gyrogonites of L. succinctum are described. The use of Lamprothamnium as a biomarker and its application in the reconstruction of Quaternary saline environments are also discussed.