Insights on the Behavior of Late Paleozoic Aquatic Crustaceans (Pygocephalomorpha?): Compound Trace Fossils from Western Argentina

We describe intergradations between the arthropod repichnial trace fossils Diplichnites gouldi (Gevers et al., 1971), Dendroidichnites Demathieu et al., 1992, and Monomorphichnus Crimes, 1970 with two distinct cubichnial traces, Gluckstadtella cooperi Savage, 1971 and Huilmuichnus santracruzensis new ichnogenus and ichnospecies. These compound ichnofossils are part of high ichnodiversity arthropod-dominated trace fossil associations from the Late Carboniferous Agua Escondida Formation of the San Rafael Basin (Argentina). The complex ichnotaxonomy of Diplichnites and the ichnospecies D. gouldi are discussed and some possible working solutions are proposed. The most likely producer of the compound trace fossils are the Pygocephalomorpha, a group of Late Paleozoic crustaceans that are recorded in nearby basins from Uruguay and Brazil. The compound trace fossils are used to infer a number of complex behaviors of pygocephalomorphs in a subaqueous setting, including caridoid (tail flip) or more primitive escape reactions, landing followed by resting and transient resting during normal walking. In addition, different gaits can be inferred from well-preserved D. gouldi, which can be correlated with contrasting trackway morphology.     

An appraisal of the fossil record for the Cirolanidae (Malacostraca: Peracarida: Isopoda: Cymothoida), with a description of a new cirolanid isopod crustacean from the early Miocene of the Vienna Basin (Western Carpathians)

Abstract:  Isopod crustaceans are rarely preserved in the fossil record. Herein, an appraisal of the fossil record for the cirolanid isopods is presented. Five genera are briefly discussed, including Bathynomus, Brunnaega, Palaega, Pseudopalaega and Cirolana. A key for the cirolanid genera known to date from the fossil record is provided based mostly on pleotelson characters. From the early Miocene of the Slovak part of the Vienna Basin, Cirolana feldmanni sp. nov. is described being only the fifth fossil Cirolana species known to date and one of the few with preserved appendages. The material exhibits preservation suggesting biphasic moulting; the mode of preservation suggests a rather short time between shedding the posterior and anterior parts of the exoskeleton instead of hours or even days known in extant taxa. As no subsequent transport or physical disturbance was inferred, the specimens can be stated as in situ preservation. From the palaeoecological point of view, it is concluded that Cirolana feldmanni sp. nov. is the first unequivocal fossil deep‐water Cirolana as suggested by the accompanied fauna.     

First Triassic record of the beetle family Permocupedidae (Insecta: Coleoptera): a peculiar example of a Lazarus taxon

The first Mesozoic representative of the extinct archostematan beetle family Permocupedidae, Frankencupes ultimus, gen. et sp. nov., is described based on two isolated elytra from the Lower Anisian (Middle Triassic) Röt Formation of Lower Franconia, Germany. The new fossil occurrence extends the range of the family from the Lower Wuchiapingian (Upper Permian) up to the Anisian, and represents a fine example of a Lazarus taxon in the fossil record of beetles.     

Danian cold‐water corals from the Baunekule facies,Faxe Formation,Denmark: a rare taphonomic window of a coral mound flank habitat

Well‐preserved cold‐water corals are comparatively rare in the fossil record. This is partly due to the very low fossilization potential of the predominantly aragonitic corals but also due to the fact that coral ecosystems of deep water are a geologically young development. A Middle Danian cold‐water coral mound complex is well exposed in Faxe Quarry, Denmark. The coral mounds are intercalated with bryozoan mounds of various sizes and form the Faxe Formation. The coral limestone displays large variations in diagenesis, and this complicates the palaeoecological reconstructions. However, the Baunekule facies from the Faxe Formation contain a well‐preserved originally aragonitic and calcitic fauna. The aragonitic skeletons have been recrystallized to calcite during early diagenesis and the excellent preservation makes taxonomic identifications straightforward. A diverse fauna of ten scleractinian coral species, nine stylasterine coral species and seven octocoral species has been described from the Baunekule facies. The fossil fauna represents an ecological niche between the dead coral framework and coral rubble on a flank of a growing Dendrophyllia coral mound with multiple colonization events. The diversity and relative abundance of the fossil scleractinian corals are comparable to the modern settings in the NE Atlantic and Mediterranean. The distribution and diversity of the octocorals and the stylasterine corals are suggested to represent coral gardens as described from modern setting in the NE Pacific. The presence of a diverse and abundant stylasterine fauna suggests a stable palaeoenvironment, probably in a bathymetric depth range of 200–400 metre.     

Decapod Crustacea from the Agrio Formation (Lower Cretaceous) of the Neuquén Basin,Argentina

Abstract: Two species of decapod crustacean are recorded from the Agua de la Mula Member of the Agrio Formation (Upper Hauterivian – Lower Barremian) of the Neuquén Basin of west‐central Argentina, namely Astacodes falcifer Bell and a new species of Palaeohomarus, P. pacificus. The preservation of the specimens is exceptional, some showing delicate compound eyes and a stridulatory apparatus, features rarely found in fossil forms. Many specimens are preserved articulated inside calcareous nodules, within dark‐grey shales. The lobster‐bearing sediments accumulated in a low‐energy marine environment and diagenetic mineralization occurred very rapidly, prior to significant decay, thus allowing exceptional preservation of specimens. Palaeohomarus was a rare genus in the Cretaceous with a palaeogeographic distribution restricted to the Mediterranean Tethys, the eastern USA and Madagascar, while Astacodes falcifer has been recorded only from Speeton (eastern England) and Neuquén.     

贵州寒武系第二统杷榔组有壳变形虫的新发现*

有壳变形虫(testate amoebae)的演化历史最早可追溯至新元古代早期, 以该时期北美、华北、挪威以及澳洲等多个地区浅海相碳酸盐岩、页岩中发现的瓶状微体化石(vase-shaped microfossils)为标志。此前认为, 显生宙的有壳变形虫最早出现在早泥盆世。长期以来, 早古生代的地层中未发现这类原生生物的明确化石证据。本研究通过对岩石样品进行常规孢粉酸泡分析处理和切磨岩石薄片, 获取原位保存的化石标本的技术方法, 从贵州东部剑河县交榜剖面出露的寒武系杷榔组(第2统第4阶)中获得数枚有壳变形虫(testate amoebae)化石标本。基于标本的显微形态特征, 并结合激光拉曼光谱等研究, 对原先记述为疑源类的Plagasphaera balangensis和P. sp. A两形态种进行重新认识和描述。由于它们在结构和形态上与一些现生的鳞壳虫目(Euglyphida)有壳变形虫极为相似, 因此将先前定为疑源类的Plagasphaera balangensis和P. sp. A两形态属、种名, 分别修订为Palaeoassulina balangensis gen. et sp. nov.和?Palaeoassulina sp. A。该发现不仅将显生宙有壳变形虫的原有化石记录从晚古生代泥盆纪向前延伸至寒武纪早期, 还为调查研究有壳变形虫的系统演化提供关键的生物化石证据。     

The oldest marine vertebrate fossil from the volcanic island of Iceland: a partial right whale skull from the high latitude Pliocene Tjörnes Formation

Extant baleen whales (Cetacea, Mysticeti) are a disparate and species‐rich group, but little is known about their fossil record in the northernmost Atlantic Ocean, a region that supports considerable extant cetacean diversity. Iceland's geographical setting, dividing North Atlantic and Arctic waters, renders it ideally situated to shed light on cetacean evolution in this region. However, as a volcanic island, Iceland exhibits very little marine sedimentary exposure, and fossil whales from Iceland older than the late Pleistocene are virtually unknown. Here, we present the first fossil whale found in situ from the Pliocene Tjörnes Formation (c. 4.5 Ma), Iceland's only substantial marine sedimentary outcrop. The specimen is diagnosed as a partial skull from a large right whale (Mysticeti, Balaenidae). This discovery highlights the Tjörnes Formation as a potentially productive fossil vertebrate locality. Additionally, this find indicates that right whales (Eubalaena) and bowhead whales (Balaena) were sympatric, with broadly overlapping latitudinal ranges in the Pliocene, in contrast to the modern latitudinal separation of their living counterparts.     

Fossil flowers and pollen ofLauraceae from the Upper Cretaceous of New Jersey

A fossil trimerous flower from the Turonian (ca. 90 MYBP, Upper Cretaceous) of New Jersey is described as a new genus in the familyLauraceae. The fossil flower is charcoalified and preserved in exceptional detail. This fossil specimen is particularly remarkable in that several pollen grains have been preserved; pollen grains ofLauraceae generally have very thin exine and are rarely preserved in the fossil record. Although the specimen is incomplete and lacks anthers, there are sufficient structural details preserved to permit an assignment to theLauraceae, as well as comparisons with the tribePerseeae. This new genus provides an important addition to our knowledge of systematic and structural diversity in CretaceousLauraceae.     

Oöcyte resorption during ovarian development in the blowfly Lucilia cuprina

Nulliparous females of a normal anautogenous strain of Lucilia cuprina mature all of their primary oöcytes after feeding ad lib on sheep's liver. Females fed measured inadequate amounts of protein-rich materia either fail to mature any oöcytes or mature less than their full complement. These mature oöcytes are smaller than in ad lib fed females. In females maturing no oöcytes, ovarian development ceases with all oöcytes in a pre-vitellogenic or early vitellogenic stage. When females mature only some of their oöcytes, the remainder are resorbed in early vitellogenesis. Few females mature less than 100 oöcytes, if they mature any at all.     

Scorpionid Resting Trace from The Lower Permian of Southern New Mexico,USA

We describe an arthropod body impression associated with arthropod trackways of the ichnogenus Stiaria from the Lower Permian (upper Wolfcampian) Robledo Mountains Formation (Hueco Group) in the Prehistoric Trackways National Monument of southern New Mexico. The probable producer of these traces was a scorpion, and we name the likely scorpionid resting trace Alacranichnus braddyi, new ichnogenus and ichnospecies. There are no prior reports of scorpionid body impressions from terrestrial settings in the fossil record.     

A Silurian myodocope with preserved soft-parts: cautioning the interpretation of the shell-based ostracod record

Ostracod crustaceans are the most abundant fossil arthropods. The Silurian Pauline avibella gen. et sp. nov., from the Herefordshire Lagerstätte, UK, is an extremely rare Palaeozoic example with soft-part preservation. Based on its soft-part morphology, especially the exceptionally preserved limbs and presence of lateral eyes, it is assigned to the myodocopid myodocopes. The ostracod is very large, with an epipod on the fifth limb pair, as well as gills implying the presence of a heart and an integrated respiratory–circulatory system as in living cylindroleberidid myodocopids. Features of its shell morphology, however, recall halocyprid myodocopes and palaeocopes, encouraging caution in classifying ostracods based on the carapace alone and querying the interpretation of their shell-based fossil record, especially for the Palaeozoic, where some 500 genera are presently assigned to the Palaeocopida.     

Lunulichnus Tuberosus Ichnogen. and Ichnosp. Nov. from the Early Eocene Wasatch Formation,Fossil Butte National Monument,Wyoming: An Arthropod-Constructed Trace Fossil Associated with Alluvial Firmgrounds

A new trace fossil, Lunulichnus tuberosus, is described from fluvial deposits of the Wasatch Formation (early Eocene) at Fossil Butte National Monument, southwestern Wyoming, USA. L. tuberosus are straight, vertical to obliquely oriented, unlined cylindrical burrows with pronounced crescent-shaped wall sculptings. In situ examples of these trace fossils are most commonly preserved as sand-filled casts emanating from the erosional bases of fluvial channel sandstone bodies into underlying floodplain mudstone/siltstone beds. L. tuberosus is interpreted as the dwelling trace of a stream-dwelling decapod crustacean. Excellent preservation of fine detail, particularly their diagnostic crescent-shaped wall sculptings, support the hypothesis that L. tuberosus were excavated in firm substrata subjacent to fluvial erosional surfaces. As such, they are interpreted as constituents of alluvial Glossifungites trace fossil assemblages.     

Early Triassic Archosaur-Dominated Footprint Assemblage from the Argana Basin (Western High Atlas,Morocco)

An assemblage of abundant and well-preserved tetrapod footprints has been discovered in the Tanamert Member (T3) of the Triassic Timezgadiouine Formation (Argana basin, western High Atlas, Morocco). It is the first fossil record from T3. Surfaces from different localities show a uniform tetrapod ichnofauna that consists of chirotherian and small lacertoid forms. The chirotherians are assigned to the plexus Protochirotherium—Synaptichnium, their trackmakers interpreted as basal archosaurs. The lacertoid imprints show close affinities with Rhynchosauroides and may reflect archosauromorphs or lepidosauromorphs. Protochirotherium—Synaptichnium assemblages are characteristic of the Early Triassic and were known previously only from units of this age in central Europe. Biostratigraphically, the European record implies a wide-spread pre-Anisian Protochirotherium—Synaptichnium dominated assemblage preceding the first appearance of Chirotherium barthii near the Olenekian-Anisian boundary. The stratigraphic position of T3 between Late Permian (uppermost T2) and Middle Triassic (T4) and the European correlatives suggest an Early Triassic age of this unit. It is the first record of Early Triassic continental deposits in Morocco. The surfaces from T3 open up perspectives for further contributions to ecology, biogeography and locomotion of early archosaurs. Furthermore, excellent outcrops and quality of footprint preservation in the Argana basin offer a potential for clarification of ichnotaxonomic and biostratigraphic issues.     

Reproductive allocation by the blow fly Lucilia sericata in response to protein limitation

Adult females of the anautogenous blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae) were fed standardized meals of liquidized liver, in quantities shown to range around the minimum required to initiate yolk deposition. Females from each feeding regime were dissected at daily intervals between 4 and 11 days of age; the number and stage of development of all oöcytes were recorded. Once an initial threshold quantity of protein was ingested, yolk deposition was initiated in all available oöcytes. Subsequently, one of two distinct developmental pathways was followed: arrested development in all oöcytes at an early stage of yolk deposition, or more extensive yolk deposition followed by progressive oösorbtion and the maturation of small batches of eggs. The proportion of females showing oösorbtion relative to arrested follicular development increased with increasing protein meal size, suggesting that the difference in response may be triggered by a second protein threshold, either side of which the arrested development or oösorbtion pathways are followed. The behaviour observed may reflect strategies to maximize reproductive output in this short‐lived, resource‐limited insect species. Flies that display arrested development may have sufficient protein to mature few if any complete eggs, but may subsequently be able to mature a full egg‐batch if they obtain further protein meals; this possibility is offset by the risk of death before finding such a meal. Flies that show oöcyte development and oösorbtion produce smaller egg batches more quickly and hence have a higher probability of achieving at least some reproductive output. By initiating yolk deposition in all oöcytes, female L. sericata retain the potential to adopt either developmental pathway, depending on subsequent protein intake.     

Oösorption in the Coleopteran Sitophilus granorius (L.)

King, P. E., Al-Khalifa, M. S. 1980. Oösorption in the coleopteran Sitophilus granarius (L.). (Department of Zoology, University College, Swansea, U.K.) — Acta zool. (Stockh.) 61(2): 79–86. The process of oösorption in the terminal oöcytes of starved specimens of Sitophilus granarius is described Starvation affects the nucleus, mitochondria and endoplasmic reticulum in both the follicle cells and the oöcyte. Glycogen disappears from the oöcyte at an early stage and islands are formed in the oö:cyte by infoldings of the combined follicle, oöcyte cell membranes.     

Determinants of oöcyte degeneration in Drosophila melanogaster

During normal oögenesis in many insects some of the oöcytes fail to mature; instead they degenerate and are resorbed. In this work oöctte degeneration was investigated in Drosophila melanogaster females and found to be limited to early vitellogenic stages (stages 8–10). Even when retained for up to 18 days by females, mature (stage 14) oöcytes showed unaltered protein patterns after separation by SDS polyacrylamide electrophoresis, indicating that protein breakdown, which is characteristic of degeneration, does not occur in chorionated oöcytes.A number of environmental parameters were shown to influence the percentage of degenerating oöcytes in females. Strong responses as reflected by increased stage-8 and 9 oöcyte degeneration were found in females subjected to suboptimal (but not starvation) medium, virgin females, females mechanically unable to oviposit, and females unable to locate suitable oviposition sites. Little or no response was seen in females subjected to crowding, however, since all of these environmental parameters except adult crowding have been shown to decrease fecundity, and therefore the rate of oöcyte production, it is suggested that oöcyte degeneration is a strategy for decreasing the rate of oöcyte production in Drosophila.     

First record of Miocene crustaceans from Hormozgan Province,Southern Iran

Four decapod crustacean species from the Middle Miocene Mishan Formation of Hormozgan Province, Southern Iran are described. Three species of leucosiid crabs represent the first fossil record for their respective genera outside the Indo-Pacific region. The oldest records for Leucosia sensu lato, Phylira sensu lato, and Arcania are from Middle Miocene deposits of the Indo-Pacific, and thus their paleobiogeographic distribution is extended for this lapse of time. Harpactocarcinus miocenicus n. sp. represents the youngest and most oriental occurrence for a typically Eocene genus, whose species are known mainly from Central Europe. This contribution represents the first formal report for Tertiary crustaceans from Iran.     

Occurrence of an in situ fern grove in the Aptian Douiret Formation, Tataouine area, South-Tunisia

A level with fern stumps was discovered in the Aptian Douiret Formation, South-Tunisia. These stumps are preserved as external moulds or casts, without any preservation of anatomical structures. These stumps are considered to be affiliated with the numerous fossil plants assigned to the fern genera Alstaettia and Piazopteris that are widely distributed in coeval strata from the same region, either as leaf imprints or as permineralized remains. The record of in situ fossil forests for the Southern Hemisphere reveals that their systematic components are different, i.e. mainly corystosperms and/or conifers, and rarely under tidal influence. The way this fern grove settled in a margino-littoral environment is discussed.     

A late Pleistocene progradational clastic shoreface succession in Jamaica: Implications for the preservation potential of the echinoid Leodia

A section in the Late Pleistocene Port Morant Formation of Jamaica shows a progradational deltaic succession passing from offshore muddy sands, through shoreface to foreshore deposits. The transition zone/lower shoreface has abundant Ophiomorpha burrows and contains common examples of the echinoid Leodia cf. sexiesperforata (Leske). Modern Leodia occur in shallow marine carbonate sands, and the Port Morant occurrence is the first record of abundant Leodia in the geological record. Despite their strong test construction that should give Leodia a high preservation potential, these echinoids have a poor fossil record because the environments in which they lived are rarely preserved. Consequently, the fossil record is biased towards species that occur in environments with high preservation potential.