Tuesday, 21 October 2014

Human remains from the Middle Pleistocene of Normandy.

Early and Middle Pleistocene Human remains are extremely rare in northern Europe, having to date been found only at a single location (Biache-Saint-Vaast) in France, as well as three locations in the UK (Swanscombe, Boxgrove and Pontnewydd) and seven sights in Germany (Sarstedt, Bilzingsleben, Weimar-Ehringsdorf, Maur, Reilingen, Steinheim and Bad Cannstatt).

In a paper published in the journal PLoS One on 8 October 2014, a team of scientists led by Jean-Philippe Faivre of the Unité Mixte de Recherchede la Préhistoireàl’Actuel: Culture, Environnement et Anthropologie at the Université de Bordeaux describe the discovery of Middle Pleistocene Human remains from an additional site in northern France, Tourville-la-Rivière in Normandy, for the first time.

Location of the open-area site of Tourville-la-Rivière and other Northwest European (north to 45˚N and west to 16˚E) contexts, contemporaries of Early and Middle Pleistocene, that have yielded Human remains. Faivre et al. (2014).

The Tourville-la-Rivière site is a gravel quarry in the Seine Valley that has produced traces of Human activity since 1967, but has not previously produced any actual Human remains. Previous finds have included 726 stone tools as well as a wide variety of animal remains, some of which show signs of processing by Humans. The stone tools include numerous Levallois blades but no Levallois cores (rocks from which the blades would have been split off), which has led to the suggestion that the blades were being imported to the site (this is significant as it is thought that the first stone tool users made the tools they needed at the site they used them, then discarded them when they were finished, as is seen to some extent in Chimpanzees; the retaining of tools for later use being a development indicative of more advanced forward planning). Non-Lavallois blades and some non-Lacallois cores have also been discovered at the site, as well as some Rocourt-type tools (which are formed in a slightly different way, producing longer blades). The site has been dated to between 183 000 and 226 000 years old.

The Tourville-la-Rivièresite: General view of the site during excavation. Faivre et al. (2014).

Human remains were discovered at the Tourville-la-Rivière site by Antoine Cottard of the Institut national de recherches archéologiques préventives at the Centre archéologique de Grand Quevilly and Aminte Thomann. The material comprises the left humerus, radius and ulna (arm bones) all being blackened and eroded. The black colouration is probably indicative of having decomposed in standing water.

The Tourville human remains in situ. The posterior and medial surfaces were the first to be made visible for the radial (# 1175) andulnar (# 1176) diaphyses, respectively, while the postero-medial surface of the humeral diaphysis (#1174) and posterior surface of the distal extremity were the first to be exposed. (A)distal extremity of the humerus, posterior face; (B) fragments of the distal portion of the humeral diaphysis.Several elements have since been refitted to the diaphysis; (C) the humeral diaphysis, medial to posteromedial face, proximal extremityto the north-west; D: radius, posterior face, proximal extremity to the north; (E) ulna, medial face, proximal extremity to the north. Dotted lines indicate the alignment of the broken part of the distal and proximal extremities of the ulna and radius. Faivre et al. (2014).

The precise taxonomy of Early and Middle Pleistocene Humans from Europe is debatable, with experts holding differing opinions as to whether Neanderthals should be seen as a different species or just a distinct population of early modern Humans. Whatever their relationship to modern Humans, the group do present a distinctive set of morphological traits which enable their identification as a distinct subset of human remains, presumably with a shared ancestry. Identification of Neanderthals usually depends on examination of the skulls and teeth of specimens, which are not present in the Tourville-la-Rivière material; identification of bones from other parts of the body is harder, as there is considerable overlap between morphologies found in Neanderthals, Modern Humans and other Early Modern Human populations. Nevertheless on this occasion Faivre et al. feel confident in assigning these bones to the Neanderthal group, as their morphology falls within a range seen in 70.5% of Neanderthal specimens, but only 8.8% of other Early Modern Humans and 2.8% of Modern Humans.

The Tourville left upper limb remains. Top: humerus; bottom left: ulna; bottom right: radius. For all the bones: A: anterior view; M:medial view; P: posterior view; L: lateral view. Faivre et al. (2014).

See also…

Ritual use of raptor claws by Neanderthals, 90 000 - 40 000 years ago.
Ritual or symbolic behaviour is generally taken as a sign of cognitive levels comparable to those of modern humans by palaeoanthropologists studying ancient human populations. The earliest signs of this are often taken as the use of red ochre by Neanderthals in Europe and Archaic modern humans in Africa, but some specialists regard this as slightly suspect, since red ochre does have non-ritual applications.

Red ochre is a dye made from the mineral hematite (Fe₂O₃). It's use by ancient humans is generally assumed to be ritual, though modern...
On Tuesday this week (26 July 2011) Bristol University announced the discovery of a carving of a speared reindeer in a cave on the Gower Peninsula. It is thought the carving could be over 14 000 years old and is possibly Britain's oldest known art.
Follow Sciency Thoughts on Facebook.

Stone tools from the Middle to Late Pleistocene of the Nefud Desert.

The Nefud Desert lies in the northwest of Saudi Arabia, and is thought to have been one of the key obstacles that early Humans, and other Hominids, had to pass as they expanded out of Africa into Southwest Asia. The area is close to the southern extent of the range of the Neaderthals, who occupied much of Europe and West Asia during the Middle Pleistocene, and it is thought that Modern Humans dispersed through the region between about 130 000 and 75 000 years ago. The Nefud Desert has yielded a number of sites from which a variety of stone tools have been collected, however while a variety of Hominid remains have been found in other areas of the Middle East, none have been found from the Nefud, making it hard to assert the identity of the Nefud toolmakers with any confidence.

In a paper published in the journal Quaternary International on 8 October 2014, a team of archaeologists led by Eleanor Scerri of the University of Bordeaux discus the results of a survey of a survey of archaeological sites in the southern Nefud Desert carried out in 2013.

The area studied is currently hyperarid, and covered by a variety of and dune structures. However it is thought to have had a wetter climate at times over the past half million years, with lakes occupying the area at about 410 000 years ago, about 320 000 years ago, about 200 000 years ago, about 125 000 years ago, from about 40 000 to 25 000 years ago and from about 10 000 to about 6000 years ago. During some of these periods it appears likely that significant lakes covered much of the area, but during others it is more likely that smaller ephemeral (temporary) lakes were scattered across the region.

In 2013 Scerri et al surveyed 12 sites in the southern Nefud, five close to the village of Khall Amayshan (numbered KAM 1-4 and 6), two near Al Raba (Rab 3 and 4), two at Khabb Musayyib (KM 1 and 2), one in the T'is al Ghadah Basin (TAG 1), one in the Tayma Wildlife Reserve (WR) and one in the Munasafiyah Basin (HIS 1).

Map of the Middle and Upper Palaeolithic sites found during the Palaeodeserts 2014 survey of the southwestern Nefud. KAM 1e5 refer to Khall Amayshan sites; KM 1e2 andKM-RM refer to the sites at Khabb Musayyib; TAG 1 refers to Ta'is al Ghadah; HIS 1 refers to a site along a line of jibal; RAB 3 and 4 refer to the Al Raba sites; WR refers to the Wildlife Reserve site. Scerri et al. (2014).

The first Khall Amayshan site (KAM 1) was first discovered in 1998 and is thought to date to between 117 000 and 99 000 years ago. The site represents a circular lake which persisted some time, laying down at least 3.24 m of layered marls, silts and sands, from which fossils of a number of freshwater Diatoms have been recovered, providing a reliable guide to both the dates of the deposits and the conditions under which they were laid down. A variety of stone tools have been recovered from these lake deposits.

Exposed lakebed and location of the sampled section at KAM 1. Paul Breeze in Scerri et al. (2014).

Scerri et al. recovered 106 stone artifacts from this site, all being of good quality and most made of quartzite, with some chert objects; the quartzite appears to come from the local region, but the chert is from further afield. Eleven cores (stones from which numerous flakes had been removed) were found, along with numerous flakes. Most were of the Levallois type (a distinctive style of tool making first described from tools from Levallois, a suburb of Paris, in the nineteenth century; flakes are chipped away from the edges of a stone core in a way that leaves it resembling a tortoise shell), which is considered to be Middle Palaeolithic. Scerri et al. suggest that the artifacts were left by toolmakers who were sporadically visiting the lake, and working stone by the lake edge.

Selected artefacts from KAM1. (1) Conjoined Levallois flake with bidirectional flaking pattern; (2) Levallois flake with centripetal flaking pattern; (3) broken Levallois flake,possibly a point, with unidirectional flaking pattern; (4) broken Levallois flake, possibly a point, with bidirectional flaking pattern; (5) Levallois flake with centripetal flaking pattern; (6) centripetally prepared preferential Levallois core; (7) double side retouched point; (8) side retouched flake; (9) refitted single platform core and flake; (10) refitted core management flakes; (11) conjoined blade. Eleanor Scerri in Scerri et al. (2014).

The second Khall Amayshan site (KAM 2) was discovered for the first time during this survey. It yielded only two poorly preserved handaxes from a marl deposit, which were not collected. However the site was recorded for potential further investigation.

The third Khall Amayshan site (KAM 3) was also discovered for the first time during this survey. It produced a small number of Late Palaeolithic artefacts from a Diatom bed. Again these objects were not collected, but the site was identified for later investigation.

Acheulean Handaxes from KAM 3. The handaxes were heavily weathered andabraded, suggesting a long surface exposure. Eleanor Scerri in Scerri et al. (2014).

The fourth Khall Amayshan site (KAM 4) appears to represent an ephemeral lake site, where lakes appeared and disappeared over a long period of time. While these have not yet been accurately dates, the site yielded a total of 1561 artefacts, from several distinct phases of activity, ranging from Acheulean (expand) to Middle Palaeolithic in nature. Some handaxes from the site were made of a distinctive rock with a ‘wood grain’ pattern, which has also been found at the KM sites and KAM 1, but which has yet to be identified.

Artefacts from KAM 4. (1) Side denticulated flake; (2) Point produced using the unidirectional convergent Levallois method; (3) Recurrent centripetal Levallois core; (4) Centripetally prepared preferential Levallois core; (5-6) Handaxes. Eleanor Scerri in Scerri et al. (2014).

The fifth Khall Amayshan site (KAM 6) consisted of lake bed deposits made up of Diatomite with preserved Crayfish burrows, overtopped by gypsum beds (evaporite deposits probably formed as the lake dried up). The site yielded several cores and flakes of the Levallois type, which were not collected, the site being recorded for further investigation later.

The first Al Raba site (RAB 3) comprises an area of about 1.16 km2 of reworked sediments, mostly gypcretes and silts, which also produced Middle Palaeolithic objects; it is unclear if these objects are also reworked. These objects were not collected, but the site was recorded for further investigation.

The second Al Raba site (RAB 4) comprised an area of lake sediments about 1.5 km to the southeast of RAB 3. This also yielded Middle Palaeolithic artifacts, but again these objects were not collected, but the site was recorded for further investigation.

The two Khabb Musayyib sites (KM 1 and KM 2) are a pair of gypsum and marl lakeshore deposits, apparently derived from the remains of a single lake-bed which has otherwise eroded away. These sites have yielded a variety of Early Palaeolithic remains, including small, finely made handaxes, a chopper core and Levallois cores and flakes. A site of material for tool-making was also found at KM 2, with sandstone and quartz cobbles along with further tools.

KM1b (mid ground) and KM2 (background, viewed from the top of KM1a, looking south-east. Paul Breeze in Scerri et al. (2014).

The Khabb Musayyib sites yielded a total of 68 artefacts, mostly made from quartzite, though one handaxe made from high grade chert was also found. The artefacts from the lakeshore at KM2 appear to date from a different period to the artifacts at the material source. 57 objects were obtained from the lakeshore deposits, 40 of these being small, well-made bifaces (cutting tools with two cutting edges), averaging 91 mm in length.

Tools from the lakeshore deposits at KM 2. (1-2) Small finished bifaces; (3) unfinished biface; (4) large finished biface; (5-6) unfished bifaces; (7) discoidal core; (8) denticulated flake. Eleanor Scerri in Scerri et al. (2014).

Artefacts from the second site, KM-2. (1) Micoquian Handaxe with missing tip; (2-3) bifaces; (4-5) Levallois cores. Eleanor Scerri in Scerri et al. (2014).

The T'is al Ghadah Basin site (TAG 1) comprises a lake bottom with several well preserved horizons yielding numerous surface fossils. On top of this series of beds a number of collections of stone tools were found. The fossil remains have been dated from the Early Pleistocene to about 410 000 years ago, while analysis of the uppermost sediments suggest ages of 328 000 to 310 000 years ago. It is unclear if the artifacts found at the site date from this period or are more recent, but if they are then they represent some of the oldest Middle Palaeolithic material found in the Nefud.

76 artefacts were recovered from TAG 1, predominantly from scatter sites in two different areas of the basin. One such scatter site produced a distinctive set of simple cores and flakes, of apparent early Middle Palaeolithic origin made from a pale amber quartzite. Cores from elsewhere in the basin were predominantly of a darker quartzite, with a few chert objects, and comprised small cores and core fragments and flakes. This tool set includes bifaces, discoidal cores, bifacial flakes, Levallois flakes and simple blade cores, suggesting a late Early Palaeolithic or early Middle Palaeolithic origin.

Flakes from TAG 1. (1-5) Retouched flakes; (6) pointed flake; (7) Levallois flake; (8) Retouched flake; (10-13) Discoidal flakes. Eleanor Scerri in Scerri et al. (2014).

The Tayma Wildlife Reserve site (WR) comprises an area of exposed bedrock with eroded channels, with some infill material, leading downwards to an exposed mudflat. The material gathered here was trapped in the erosion channels. Scerri et al. recovered 94 flakes, two bifaces and 35 cores from this site, most made of local rock, but including some quartz, limestone, chert and rhyolite also used. This site is thought to contain material from several phases of occupation, but is of a broadly Middle Palaeolithic origin.

Flakes from the Wildlife Reserve site. (1-5) Single platform and discoidal flakes; (6-8) Levallois flakes; (9) Retouched Levallois point, probably recycled; (10) Levallois flake; (11) large, cortical flakes. Eleanor Scerri in Scerri et al. (2014).

Cores from the Wildlife Reserve site. (1-2) Centripetally prepared preferential Levallois cores; (3) recurrent centripetal Levallois core; (4) Single platform core; (5) bidirectional Levallois point core; (6-7) discoidal cores; (8) single platform core; (9) multiple platform core; (10-11) bifaces. Eleanor Scerri in Scerri et al. (2014).

The Munasafiyah Basin  site (HIS 1) comprised a scattered Palaeolithic site along the lower slopes of a jibal (line of rocky hills). The site featured considerable rock art, as well as artefacts of Early and Middle Palaeolithic origin, including handaxes, bifaces, Levallois cores and flakes, débordant flakes, core tablets and other material. All appeared to be made of local quartzite, suggesting the toolmakers were using scree slopes at the foot of the jebel as a source of material. None of the material was collected, but the site was marked for further investigation.

The sites yielded a great diversity of Late Pleistocene material, but very little from the Holocene, suggesting that conditions were considerably more favourable in the Nafud then. The Early Palaeolithic material suggests a long period of continuous occupation of the area, associated with fairly stable lakes, which existed for long periods of time. The Middle Palaeolithic material is more scattered and suggests more temporary occupation, associated with ephemeral lakes, which were not always present. Scerri et al. suggest that the area was occupied repeatedly from neighbouring areas, such as Jordan and the Sinai, when conditions were favourable, then abandoned again when the lakes dried up.

See also…

http://sciencythoughts.blogspot.co.uk/2013/10/dating-toba-eruption.html Dating the Toba Eruption.                                    Sometime between 69 000 and 77 000 years ago a large volcano occupying the site of the current Lake Toba on northern Sumatra underwent what is believed to have been the largest volcanoc eruption of the Quaternary Period, covering much of south Asia in around 15 cm of ash, and probably causing...
http://sciencythoughts.blogspot.co.uk/2013/10/toolmaking-in-northeastern-thar-desert.html Toolmaking in the northeastern Thar Desert 95 600 years ago.                                                                 The Thar Desert covers over  200,000 km² of land in the northwest part of the Indian Subcontinent, straddling the border between Pakistan and India. It marks the...
http://sciencythoughts.blogspot.co.uk/2012/02/20-000-year-old-stone-huts-from.html 20 000 year old stone huts from Kharaneh in Eastern Jordan.                                                                       The earliest stone structures are generally associated with the Epipalaeolithic Natufian culture of Southwest Asia (the term Epipalaeololithic applies to cultures outside the extent of the last glaciation that showed the same...
Follow Sciency Thoughts on Facebook.

A giant agglutinated Foraminiferan from the Western Mediterranean.

Foraminiferans are Amoeba-like single-celled organisms found either free-floating or attached to surfaces in marine ecosystems. Many build ornate tests (shells) from calcium carbonate, and planktonic forms are widely used in biostratigraphy (the use of small fossils to date sedimentary rocks), but others lack the ability to produce their own biominerals, and instead construct protective coverings by cementing together other items.

In a paper published in the journal Zootaxa on 10 June 2013, a team of scientists led by Manuel Maldonado of the Centro de Estudios Avanzados deBlanes describe a new species of agglutinated Foraminiferan from the Seco de Palos seamount in the Western Mediterranean.

The new species is placed in the genus Spiculosiphon, and given the specific name oceana, in honour of the non-profit organization for ocean conservation OCEANA, which was responsible for the collection of the samples from which the species is described. Spiculosiphonoceana lives attached to a substrate by a long stalk, both the stalk and the main body being covered by agglutinated Sponge spicules, though these are arranged laterally in a slight spiral around the stalk but radiate out from the body.

(A) General view of the Spiculosiphon oceana. (B) Detail of capitate region of the holotype, showing the globelike, central structure and the radiating tracts of spicules. Maldonado et al. (2013).

Spiculosiphon oceana is a giant by Foraminiferan standards, reaching in excess of 4 cm in length. It is only the second species assigned to the genus Spiculosiphon; the first species, Spiculosiphon radiata is also large, but less so than Spiculosiphon oceana, reaching only about 2 cm. This species was described from specimens collected off the coast of Norway in 1964.

Maldonado et al. note that both species of Spiculosiphon show remarkable convergent evolution with some small species of Carnivorous Sponge, using scavenged Sponge spicules to build a body very similar in form to the Sponge; both organisms then trapping relatively large prey and dissolving it externally.

(A) View of the carnivorous sponge Asbestopluma hypogea soon after trapping a small Copepod. The sponge isdisplaying the spiny-headed morphology, which is typical after a period of starvation in order to maximize the chances of new prey capture. (B) View of the capitate region of Spiculosiphon oceana for a comparison with the body shape of the Carnivorous Sponge. Maldonado et al. (2013).

Maldonado et al. further observe that many agglutinated Foraminiferans appear to have a preference for Sponge spicules when incorporating material into their tests, while tending to reject other sources of biogenic silica such as Diatom shells. They suggest that this may be linked to the ancient nature of the group; the earliest Foraminiferans are thought to have appeared about 770 million years ago, in the Middle Cryogenian Period (about the same time as the earliest Sponges), while the Agglutinated Foraminiferans are thought to have arisen in the late Ediacaran or early Cambrian, about the same time as the earliest Siliceous Sponges (Sponges producing spicules made of silica). The earliest Diatoms appeared in the Early Jurassic, about 199 million years ago, by which time Agglutinated Foraminiferans had evolved to use Sponge spicules wherever possible.

That said, they also acknowledge that while Sponge spicules and Diatom tests are generally considered to be chemically identical, Sponge spicules do persist for much longer in seawater without dissolving (which clearly has advantages when using recycled material as a construction material), leading Maldonado et al. to suggest their may be different trace elements or compounds in the two materials, which both contributes to the more durable nature of the Sponge spicules and is detectable to the Foraminiferans.

SEM micrograph of stalk. (Tightly packed needle-like spicule fragments, with no obvious cement betweenthem. Some debris (d) has flocculated on the spicules. Note that the silica of some of the oldest spicules started dissolving, asindicated by the occurrence of tiny cavities and pits (p) at their surface. Dissolution cavities are to be distinguished fromaccidental breakages (b) caused to the stalk during collection or laboratory manipulation. Maldonado et al. (2013).

Maldonado et al. also record patches of colour on the stalk of Spiculosiphon oceana which appear to derive neither from the mineralogy of the spicules nor any fouling organism living external to the stalk. Instead they suggest this may be caused by photosynthetic symbionts growing inside the stalk (beneath the translucent spicules). Other species of Agglutinated Foraminiferans have been recorded to host a variety of Dinoflagellates, Diatoms, unicellular Chlorophytes (Green Algae), unicellular Rhodophytes  (Red Algae) and Cyanobacteria; the colour of the markings on the Spiculosiphon oceana stalks tending to suggest Dinoflagellates, Rhodophytes, or Cyanobacteria might be present, though they were unable to confirm this.

The stalk in showing a region in which the translucent spicule wall gets a brownish to purplish coloration. Maldonado et al. (2013).

Finally Maldonado et al. report the presence of a Calcareous Foramiferan test attached to the stem of one of the specimens (presumably the remains of a past meal) and not that both this test and the adjacent area of the stem show raised levels of the element tellurium. This is a very rare element, and has never been reported in any Foraminiferan before (nor many other organisms). It is unclear whether the source of this tellurium is the Calcareous or the Agglutinated Foraminiferan, nor exactly what biological process it could have been used in.

(C) Detail of a calcareous foraminifer (f) externally attached to the wall of one ofthe collected stalks. Note that a triaene (t) has been incorporated into the test and that some debris (d) hasflocculated on the stalk. Maldonado et al. (2013).

See also…

Golden Algae (Chrysophyceae) are photosynthetic eukaryotic microbes (i.e. single celled organisms that posses cell nuclei similar to those found in the cells of animals and plants, but unlike bacteria which do not), found throughout the world, predominantly in fresh water. The group is mostly poorly studied, with the exception of a few species which are toxic to Fish.

http://sciencythoughts.blogspot.co.uk/2013/09/four-new-species-of-fossil-diatom-from.html Four new species of fossil Diatom from the western United States.                                              Diatoms are single celled algae related to Kelp and Water Moulds. They are encased in silica shells with two valves. During reproduction the cells divide in two, each of which retains one valve of the shell, growing a new opposing valve, which is slightly smaller and fits flush within the older valve. This means that the Diatoms grow smaller with each new generation, until they...
http://sciencythoughts.blogspot.co.uk/2012/02/oldest-animals-pre-ediacaran-sponges.html The oldest animals - Pre-Ediacaran Sponges from Namibia(?)                                                             Sponges are curious creatures. They are considered to be animals as they are multicellular and some of them have fixed body shapes, however they show no cell differentiation, and can be broken down into individual cells (by, for example, forcing them through a sieve) and they will re-assemble themselves without apparent ill-effect. In some ways they are more like colonial protists than true animals. Biologists have long regarded them as the most primitive animal...

Follow Sciency Thoughts on Facebook.

A new species of Horseshoe Crab from the Late Jurassic Owadów-Brzezinki Lagerstätte of Central Poland.

Horseshoe Crabs, Xiphosurida, first appeared in the fossil record during the Ordovician, at least 480 million years ago, and are still found today in Southeast Asia and along the east coast of North America. They are not true Crabs, nor even Crustaceans, but a distinct group of Arthropods related to the extinct Trilobites and terrestrial Arachnids (Spiders, Scorpions and Mites etc.). The group are remarkably morphologically conservative, having changed very little since they first appeared, and even less since the early Mesozoic, when forms very similar to those alive today first appeared.

In a paper published in the journal PLoS One on 2 October 2014, AdrianKin of the Society of Friends of Earth Sciences in Warsaw and Błażej Błażejowski of the Institute of Paleobiology at the Polish Academy of Sciences, describe a new species of Horseshoe Crab from the Late Jurassic Kcynia Formation at the Owadów-Brzezinki Quarry in Central Poland.

The new species is placed in the extant genus Limulus and given the specific name darwini, in honour of the Victorian naturalist and evolutionary biologist Charles Darwin (1809-1882). The species is described from nine specimens, although these all preserve only the dorsal surface, and are thought to be moulted exoskeletons of juveniles. Kin and Błażejowski note that such moulted exoskeletons are the most common form of Xiphosurid fossils encountered, and that most are from juveniles rather than adult specimens; the Crabs keep growing for their entire lives, but have a distinct juvenile phase when they grow rapidly and moult several times a year, followed by an adult phase when they grow much more slowly and typically moult only once per year.

Three-dimensionally preserved representative of the Late Jurassic Limulus darwini, preserved as slightly compressed and juxtapositioned prosoma and opisthosoma. Kin & Błażejowski (2014).

Although only the dorsal surface of Limulus darwini is preserved, this is remarkably similar to the modern Limulus polyphemus from the east coast of North America, to a degree that Kin and Błażejowski feel merits explanation.

Comparison of modern Limulus polyphemus (left) and oldest known member of the genus Limulus darwini (right) fromCorbulomima horizon of unit III from Late Jurassic (upper Tithonian = Middle Volgian) sedimentary sequence at Owadów-BrzezinkiQuarry (central Poland). (X), (Y) and (Z) – details emphasized, are most substantial morphological difference between both these forms. (cl) -cardiac lobe; (opr) – opisthosomal rim; (pa) – posterial area.Morphological elements of L. darwini exoskeleton not known from the fossil record (i.e.movable spines and telson) emphasized in grey. Kin & Błażejowski (2014).

Kin and Błażejowski note that while Horseshoe Crabs show remarkable morphological conservatism, they are in many ways strikingly flexible organisms. All four modern species are highly tolerant of wide fluctuations in temperature and salinity; the North American Limulus polyphemus lives happily in waters as cool as 1˚C off the coast of Maine and as warm as 30˚C off the coasts of Florida and Mexico, while the Asian Carcinoscorpius rotundicaudata migrates around 150 km up the Hooghly River from fully marine to fully freshwater conditions.

Horseshoe Crabs are also remarkably broad in their dietary habits. Most species prey predominantly on Bivalves, but also eat a variety of Worms and Snails, and will feed on a wide range of invertebrates, such as Echinoderms and Crustaceans, when they are available, and will even consume small Fish and plant material.

The precise ecology of extinct organisms is always subject to debate, but the fossils of the Owadów-Brzezinki Quarry are dominated by Bivalves of the genus Corbulomima, which is also believed to have been tolerant of wide fluctuations in salinity (many of its closest living relatives exhibit this trait) and which also produces fossils of fully marine species such as Ammonites, and a variety of terrestrial fossils, such as Grasshoppers and Beetles, suggesting at least periodic inundations with freshwater

Horseshoe Crabs are also known from the Solnhofen Limestone in Germany, deposits roughly contemporaneous with those at Owadów-Brzezinki, where the exceptionally high preservation of the fossils has been linked to high salinity in lagoons, which excluded detritavores that might have preyed on the dead animals.

This suggests that two of the survival traits seen in modern Horseshoe Crabs, a tolerance of changing water salinity and a diet based upon (usually widely available) Bivalves but combined with a willingness to switch to other prey, were already seen in the group in the Jurassic.

Kin and Błażejowski also note that while Horseshoe Crabs show unusually little morphological variation, they show typical levels of genetic variation for more variable species, suggesting that individual Crabs vary in their environmental tolerances; this can be an advantage in times of environmental crises, as it makes it more likely that some members of a group will always survive.

Finally Kin and Błażejowski observe that the blood of Horseshoe Crabs is known to have remarkable anti-bacterial properties, a trait shared with other groups that have changed relatively little for very periods of time, such as Sharks and Crocodiles.

Horseshoe Crabs are members of a diverse group or organisms known popularly as ‘living fossils’, which also includes groups such as Lingulid Brachiopods and Ginko Trees. However Kin and Błażejowski feel that this term is somewhat imprecise, as it also includes relict members of ancient groups such as the Ceolocanth Latimaria and the Nautilid Nautilus, which are not particularly similar to earlier members of the same groups. Instead they propose the adoption of a new term ‘stabilomorphism’, to describe species that have remained essentially similar in form for periods in excess of 65 million years (a definition which would also include fossil groups that remained stable for long periods of time but which have no living representatives)

See also…

The term lagerstätte is used by Palaeontologists to describe a particularly rich fossil source; a site where fossils are either exceptionally numerous or exceptionally well preserved (or, ideally, both). One of the best known of these is the Solnhofen Limestone, or Solnhofen Plattenkalk, which formed in the early Tithonian,  towards the end of the Jurassic, as a result of intense global...

Mygalomorph Spiders (Tarantulas and related species) are considered to be one of the most ancient groups of Spiders. They have two pairs of book lungs (many other Spiders have lost a pair) and downward pointing, rather than opposable fangs, again considered to be a primitive state in Spiders. Many species of Mygalomorph attain large sizes, all have flattened, disk-shaped bodies (rather than the more globular bodies of most other Spiders), and most are ambush predators.

Trilobites were a group of Arthropods that flourished throughout the Palaeozoic, but died out at the end of the Permian. They are abundant and well studied fossils, but little is known of their internal anatomies.

Follow Sciency Thoughts on Facebook.

A fossil Dolphin from the Late Miocene of Hokkaido, Japan, which may be the oldest True Dolphin.

Dolphins, Delphinidae, are the most diverse group of Whales (or indeed any form of Marine Mammals) alive today, with 36 described species including charismatic animals such as Bottlenose Dolphins and Killer Whales. Historically a large number of fossils have also been assigned to this group, but the vast majority of these are no longer considered to be True Dolphins. Twelve fossil Dolphin species are currently widely accepted, all from the Pliocene or later and the majority from Italy. The oldest known True Dolphin is thought to be an undescribed specimen from the Late Miocene of California (LACM 52147), though this specimen lacks a head so its precise classification is hard to determine.

In 1977 palaeonotologist Hideo Horikawa described a fossil Dolphin from the Late Miocene Mashike Formation of Hokkaido Island, Japan, however this description was published in Japanese, and has received little attention outside Japan. Horikawa placed the specimen in the extant genus Stenella, giving it the specific name kabatensis. However the original description apparently contains a number of inaccuracies, and the genus Stenella has recently been shown to be polyphyletic (i.e. the five living species placed within the genus are not one-another’s closest relatives) by a genetic analysis, which is likely to lead to the reassignment of a number of Dolphin species in the near future.

In a paper published in the Journal of Vertebrate Palaeontology on 6 May 2014, Mizuki Marakami of the Graduate School of Creative Science & Engineering at Waseda University, Chieko Shimada of the Mineral Industry Museum at Akita University and the Geological Survey of Japan, Yoshinori Hikida of the Nakagawa Museum of Natural History, Yuhji Soeda of the Historical Museum of Hokkaido and Hiromichi Hirano of the Department of Earth Science at Waseda University redescribe Stenella kabatensisas Eodelphis kabatensis (Eodelphis meaning ‘Dawn-Dolphin’).

The specimen comprises a partial skull lacking the rostrum (snout) but having both mandibles and a number of teeth. Marakami et al. feel confident assigning this specimen to the Delphinidae, making it the oldest known member of the group. The specimen is at least 7.6 million years old, and probably between 8.5 and 13 million years old, though Marakami et al. suggest dates older than 9 million years are less likely.

The skull of Eodelphis kabatensis. Photograph of the skull whitened with ammonium chloride. (Top left) Dorsal view, (bottom left) left lateral view, (top right) anterior view, (bottom right) antereoventral view. Marakami et al. (2014).

A phylogenetic analysis suggested that Eodelphis kabatensisis more closely related to the living Orcinas orca (Killer Whale) than any other extant Dolphin, rather than being close to the common ancestor of all Dolphins. This supports previous molecular studies, which suggests that the group diversified earlier in the Miocene.

See also…

The Squalodelphinidae are a small group of small to medium-sized Toothed Whales known from the Miocene of Europe and North and South America. They are thought to be related to the modern Asian River Dolphin, Platanista gangetica, which lacks any close living relatives. The group is not well understood, with most described specimens being fragmentary in nature.

Porpoises (Phocoenidae) are small Whales, related to Dolphins (Delphinidae). They tend to have shorter snouts than Dolphins, with flattened, spade-shaped teeth, as opposed to the conical, pointed teeth of Dolphins. They are among the smallest and shortest lived Whales, ranging from 1.2 to 2.3 m in length and typically reaching sexual maturity at about eight...

Bottlenose Dolphins (Tursiops truncatus) are predatory Ceteceans, which primarily hunt small Fish. They are intelligent, social animals...

Follow Sciency Thoughts on Facebook.

The Orionid Meterors.

The Orionid Meteors are a prolific meteor shower appearing in late October each year and peaking on the nights of 21-22 October, when the shower can produce 50-70 meteors per hour, originating in the constellation of Orion (above and to the right of Orion's right shoulder). This makes them both one of the more prolific meteor showers, and one of the easiest for an amateur enthusiast to locate the radiant of (apparent point of origin).

 The radiant of the Orionid Meteors. Astro Bob.

The shower is caused by the Earth passing through the trail of Halley's Comet (technically Comet P1/Halley), and encountering dust from the tail of this comet. The dust particles strike the atmosphere at speeds of over 200 000 km per hour, burning up in the upper atmosphere and producing a light show in the process. 
The Earth does not need to pass close to Halley's Comet for the meteor shower to occur, it simply passes through a trail of dust from the comet's tail that is following the same orbital path. Halley's Comet only visits the Inner Solar System once every 75 years, last doing so in 1986. 
See also...
The Alpha Aurigid Meteor shower occurs each year between 25 August and 6 September, peaking between 11.30 pm GMT on 31 August and 0.30 am GMT on 1 September. However the shower is notoriously hard to observe, having been recorded only in the years 1911, 1929, 1930, 1935, 1979, 1980, 1986, 1994 and 2007 (some of these observations occurred before the 'official' discovery of the shower by Cuno Hoffmeister and Artur Teichgraeber in 1935, but have subsequently...

The Perseid Meteor shower lasts from late July to early September each year, and are expected to be at a peak on 12-13 August 2014, slightly after the Full Moon on 10 August, which may make the meteors harder to spot than when they occur at darker times of the month. At the peak of the shower there can be 50-100 meteors per hour. The Perseids...

The Eta Aquarid Meteor Shower will be at a peak on Monday 5/Tuesday 6 May 2014, with up to 45 meteors per hour at it's peak, radiating from the constellation of Aquarius. This does not spend long above the horizon in the northern hemisphere at this time of year, but potentially could produce good shows before dawn on the 4-6 May...

Follow Sciency Thoughts on Facebook.

Thursday, 16 October 2014

Three new species of Sapygid Wasps from Vietnam and Sumatra.

Sapygid Wasps are a widespread in northern Eurasia and North America, but considered rare elsewhere and are unknown in Australia, although the group are not well studied, and their distribution may be wider than realised. To date only a few species have been described from South and East Asia, although the oldest known fossil member of the group comes from Cretaceous Burmese Amber, suggesting that the group either originated in this region or has existed there for a very long time. The Wasps are cleptoparasites of solitary Bees, laying their eggs within the Bees’ nests, where the young Wasps consume both the larvae of the Bees and the food that their mothers provision them with.

In a paper published in the journal ZooKeys on 13 January 2014, Cornelisvan Achterberg of the Department of Terrestrial Zoology at the NaturalisBiodiversity Center in Leiden, The Netherlands, describes two new species of Sapygid Wasps, from Vietnam and Sumatra. Both are placed in the genus Parasapyga, which currently contains only a single species, Parasapyga moelleri, which has been recorded from Sikkim State in India and Sumatra, although van Achterberg considers the Sumatran population of this species to be different from the Sikkim population (which was described first) and also describes this as a new species.

The first new species is named Parasapyga boschi, after the scientific illustrator Erik-Jan Bosch of Leiden, for his excellent illustrations of the Hymenoptera (Wasps, Bees and Ants). The species is described from a single female Wasp collected in Cát Tien National Park in southern Vietnam. In is 18.7 mm in length and black in colour with a reddish brown abdomen.

Parasapyga boschi, female specimen. Erik-Jan Bosch in van Achterberg (2014).

The second new species is named Parasapyga yvonnae, after Yvonne van Nierop, who helped in the collection of the specimen from which the species is named, for her efforts in collecting in North Sumatra. The species is described from a single female specimen from North Sumatra. The specimen is 13.9 mm in length, black with an orange-red abdomen.

Parasapyga yvonnae, female specimen. Van Achterberg (2014).

Finally van Achterberg elevates a population of Wasps previously described from South Sumatra as a subspecies of Parasapyga moelleri to full species status. This population was formerly known as Parasapyga mölleri walshae, and now becomes Parasapyga walshae (modern taxonomy no longer allows accents in species naming, though these are sometimes encountered in older species; in this case the ‘ö’ has been replaced with ‘oe’ to keep the pronunciation the same).

Parasapyga walshae, female specimen. Van Achterberg (2014).

See also…

The Betylobraconinae are a group of Braconid Wasps (small parasitoid Wasps that lack stings and which will lay more than one egg on a host Insect) found in Australia, New Guinea and New Caledonia. They are abundant within their range, but their biology is poorly...

Braconid Wasps are small parasitoid wasps (Wasps whose larvae grow inside the bodies of a living animal host) targeting a variety of Insect and Spider species. They are unusual in that they will lay multiple eggs within the same host (most parasitoid Wasps lay a single egg on each host), thereby allowing multiple larvae to...

Platygastrid Wasps are a large group of (mostly very small) parasitoid Wasps (Wasps whose larvae develop inside the bodies of a living animal host), found across the globe. They have a long fossil record, being...

Follow Sciency Thoughts on Facebook.