For more than a century we have known that a high diversity of arthropod species lives in close relationship with army ant colonies. For instance, several hundred guest species have been described to be associated with the Neotropical army ant Eciton burchellii Westwood, 1842. Despite ongoing efforts to survey army ant guest diversity, it is evident that many more species await scientific discovery.
Results:
We conducted a large-scale community survey of Eciton-associated symbionts, combined with extensive DNA barcoding, which led to the discovery of numerous new species, among them a highly specialized histerid beetle, which is formally described here. Analyses of genitalic morphology with support of molecular characters revealed that the new species is a member of the genus Nymphister. We provide a literature review of host records and host-following mechanisms of Eciton-associated Haeteriinae demonstrating that the new species uses an unusual way of phoretic transport to track the nomadic habit of host ants. Using its long mandibles as gripping pliers, the beetle attaches between the ants’ petiole and postpetiole. The beetles specifically attach to medium-sized ant workers, thus participating as hitchhikers in the regular colony emigrations of the single host species Eciton mexicanum Roger, 1863.
Conclusion:
By providing tools for reliable species identification via morphology and DNA barcodes for hitherto unknown army ant guest species, we set the baseline for studies targeting the ecological and evolutionary dynamics in these species-rich host-symbiont communities.
Keywords: Phoresy, Social parasitism, Myrmecophile, Eciton, Host specificity, Nymphister, Army ants, Specialization, Symbiosis
Nymphister kronaueri
Etymology. We dedicate this species to Daniel Kronauer, an avid field biologist and long-time army ant researcher, who discovered the species during an Eciton mexicanum s. str. colony emigration.
Distribution. Known only from the type locality, i.e. La Selva Biological Station, a lowland Atlantic rainforest in Costa Rica.
Conclusions
Despite the enduring efforts to explore the microcosm of army ant-associated arthropods, a large proportion of unknown biodiversity still exists today. Myrmecophile communities of army ant species other than E. burchellii and E. hamatum have not been intensively studied, and thus it can be expected that many more species with fascinating adaptations still await scientific discovery. The present study is an example demonstrating the benefits of a combined approach, using morphology and DNA barcodes, to discover and describe new species in ant-myrmecophile communities.
Christoph von Beeren and Alexey K. Tishechkin. 2017. Nymphister kronaueri von Beeren & Tishechkin sp. nov., An Army Ant-associated Beetle Species (Coleoptera: Histeridae: Haeteriinae) with An Exceptional Mechanism of Phoresy. BMC Zoology. 2:3. DOI: 10.1186/s40850-016-0010-x
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Chelicerata represents a vast clade of mostly predatory arthropods united by a distinctive body plan throughout the Phanerozoic. Their origins, however, with respect to both their ancestral morphological features and their related ecologies, are still poorly understood. In particular, it remains unclear whether their major diagnostic characters were acquired early on, and their anatomical organization rapidly constrained, or if they emerged from a stem lineage encompassing an array of structural variations, based on a more labile “panchelicerate” body plan.
Results
In this study, we reinvestigated the problematic middle Cambrian arthropod Habelia optata Walcott from the Burgess Shale, and found that it was a close relative of Sanctacaris uncata Briggs and Collins (in Habeliida, ord. nov.), both retrieved in our Bayesian phylogeny as stem chelicerates. Habelia possesses an exoskeleton covered in numerous spines and a bipartite telson as long as the rest of the body. Segments are arranged into three tagmata. The prosoma includes a reduced appendage possibly precursor to the chelicera, raptorial endopods connected to five pairs of outstandingly large and overlapping gnathobasic basipods, antennule-like exopods seemingly dissociated from the main limb axis, and, posteriorly, a pair of appendages morphologically similar to thoracic ones. While the head configuration of habeliidans anchors a seven-segmented prosoma as the chelicerate ground pattern, the peculiar size and arrangement of gnathobases and the presence of sensory/tactile appendages also point to an early convergence with the masticatory head of mandibulates.
Conclusions
Although habeliidans illustrate the early appearance of some diagnostic chelicerate features in the evolution of euarthropods, the unique convergence of their cephalons with mandibulate anatomies suggests that these traits retained an unusual variability in these taxa. The common involvement of strong gnathal appendages across non-megacheirans Cambrian taxa also illustrates that the specialization of the head as the dedicated food-processing tagma was critical to the emergence of both lineages of extant euarthropods—Chelicerata and Mandibulata—and implies that this diversification was facilitated by the expansion of durophagous niches.
Diagnosis (emended from Størmer, 1944). Euarthropods with the following characters: Cephalic shield encompassing at least four pairs of appendages with well-developed endopods; originally, presence along body of at least one pair of appendages with basipod differentiated into a well-sclerotized gnathal sclerite bearing setae or teeth (“gnathobasic appendage”); third gnathobasic cephalic appendage also part of groundplan; post-cephalic endopods terminating in a trident of claws with various arrangements.
Order Habeliida, ord. nov. Aria and Caron
Type family. Habeliidae Simonetta and Delle Cave, 1975.
Other included taxa. Sanctacarididae Legg and Pates, 2016.
Diagnosis. Arachnomorph arthropods with the following characters: Cephalic shield with sub-triangular, sub-horizontal pleural expansions and with antero-lateral notches accommodating pair of lateral compound eyes with no peduncle; cephalic shield with large mesio-dorsal bulge accommodating stomach; five pairs of anterior, slender and segmented antennule-like exopods likely inserted below the eyes and dorsally to other head appendages; on ventral side of head, reduced pair of appendages inserted anteriormost (presumed in Sanctacarididae), followed by five pairs of appendages composed of gnathobasic basipods increasing in size posteriad and bearing seven-segmented spinose/setose enditic endopods projecting anteriad; trunk bearing paddle-like exopods fringed with thin lamellae.
Remarks. We maintain the family Sanctacarididae erected by Legg and Pates [33], since 10 trunk segments and a spatulate telson remain diagnostic of Sanctacaris uncata, Utahcaris orion [33] and Wisangocaris barbarahardyae [35]. The affinity of Messorocaris magna [34] is less clear, but the peculiar shape of its trunk pleurae may place it in its own family.
Habelia had previously been assigned to the orders Aglaspina by Walcott and Emeraldellia by Størmer [36]. Given the lack of cladistic support for these taxa, which would be para- or polyphyletically nested within Arachnomorpha, the lack of redescription for Molaria, and the fact that their diagnoses should be extensively revised in light of the new data gathered on aglaspidids and Emeraldella, we have not reused Aglaspina or Emeraldellia herein.
Family Habeliidae Simonetta and Delle Cave, 1975. Type genus.Habelia Walcott, 1912.
Diagnosis. Habeliidan euarthropods with the following characters: Body elongate, 19-segmented, divided into three distinct tagmata: cephalon (or “prosoma”) of seven segments (or eight somites) and trunk (12 segments) composed of a five-segmented thorax (or “mesosoma”) and eight-segmented post-thorax (or “metasoma”); trunk tagmatization based on discrete limb differentiation between thorax and post-thorax; posteriormost cephalic appendage (7th) similar to thoracic appendages, all characterized by a cheiromorph morphology: large undifferentiated basipods, well-developed seven-segmented endopods without endites, and paddle-like exopods fringed with oblanceolate lamellae; telson elongate.
Remarks. We hereby establish a diagnosis for the family Habeliidae, as the original publication of the taxon was not associated with one [39]; we also formalize diagnoses and descriptions for Habelia optata hereafter. The genus Thelxiope was also included in Habeliidae by Simonetta and Delle Cave; however, the presence of eight post-cephalic tergites and a pygidium would rather seem to indicate a relationship with Mollisonia [54, 55]. Thelxiope is therefore removed from Habeliidae.
Genus Habelia Walcott, 1912.
Type species.Habelia optata Walcott, 1912.
Diagnosis. Habeliid arthropod with the following characters: Post-ocular lateral and postero-lateral cephalic margins as well as pleural margins of trunk segments adorned with triangular spines; cuticular surface of cephalon and posterior portion of trunk segments richly adorned with small blunt spines/tubercles; cephalic gnathobases with elongate proximal “arm”; gnathobasic teeth differentiated antero-posteriorly (slender and long to short and stout); cephalic endopods with setal brush on podomeres 5 and 6; five-segmented thorax bearing strong biramous appendages with robust, clawed endopods and long basipods; very long (subequal to slightly greater than head and trunk length) bipartite telson, with a long, dentate proximal portion adorned with lateral spines, and a short distal portion about 1/3rd as long as proximal portion.
Cédric Aria and Jean-Bernard Caron. 2017. Mandibulate Convergence in An Armoured Cambrian Stem Chelicerate. BMC Evolutionary Biology. 17:261. DOI: 10.1186/s12862-017-1088-7
A 508-million-year-old sea predator with a 'jackknife' head phy.so/433048787@physorg_com
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Archaeopteryx is an iconic fossil that has long been pivotal for our understanding of the origin of birds. Remains of this important taxon have only been found in the Late Jurassic lithographic limestones of Bavaria, Germany. Twelve skeletal specimens are reported so far. Archaeopteryx was long the only pre-Cretaceous paravian theropod known, but recent discoveries from the Tiaojishan Formation, China, yielded a remarkable diversity of this clade, including the possibly oldest and most basal known clade of avialan, here named Anchiornithidae. However, Archaeopteryx remains the only Jurassic paravian theropod based on diagnostic material reported outside China.
Results
Re-examination of the incomplete Haarlem Archaeopteryx specimen did not find any diagnostic features of this genus. In contrast, the specimen markedly differs in proportions from other Archaeopteryx specimens and shares two distinct characters with anchiornithids. Phylogenetic analysis confirms it as the first anchiornithid recorded outside the Tiaojushan Formation of China, for which the new generic name Ostromia is proposed here.
Conclusions
In combination with a biogeographic analysis of coelurosaurian theropods and palaeogeographic and stratigraphic data, our results indicate an explosive radiation of maniraptoran coelurosaurs probably in isolation in eastern Asia in the late Middle Jurassic and a rapid, at least Laurasian dispersal of the different subclades in the Late Jurassic. Small body size and, possibly, a multiple origin of flight capabilities enhanced dispersal capabilities of paravian theropods and might thus have been crucial for their evolutionary success.
Keywords: Maniraptora, Anchiornithidae, Late Jurassic, Biogeography, Radiation
Fig. 1 Overview of the “Haarlem specimen”, holotype of Ostromia crassipes (Meyer, 1857). Counterslab, Teylers Museum TM 6929 (left) and main slab, TM 6928 (right).
Definition. Anchiornithidae is a stem-based taxon defined as all maniraptoran theropods that are more closely related to Anchiornis huxleyi than to Passer domesticus, Archaeopteryx lithographica, Dromaeosaurus albertensis, Troodon formosus, or Oviraptor philoceratops.
Ostromia gen. nov.
Ostromia crassipes von Meyer, 1857
Holotype. Teylers Museum TM 6928, 6929, part and counterpart of a fragmentary skeleton.
Locality and horizon. Jachenhausen locality, near Riedenburg, Bavaria, Germany. Early Tithonian laminated limestones of the Painten Formation.
Etymology. The generic name honours the late John Ostrom, who identified the Haarlem specimen as a theropod.
Conclusions
A re-evaluation of one of the twelve skeletal specimens referred to the ‘Urvogel’ Archaeopteryx, the Haarlem specimen, revealed that this specimen represents a separate taxon, Ostromia crassipes. Phylogenetic analysis identifies Ostromia as the first representative of the basal avialian clade Anchiornithidae outside eastern Asia. In combination with a biogeographic analysis, a rapid radiation of maniraptoran theropods in eastern Asia with a subsequent dispersal of many lineages in the Late Jurassic is indicated; dispersal of maniraptorans was facilitated by small body size of basal members of all clades and, possibly, several independent acquisitions of flight capabilities. In the fragmenting world of Pangean break-up during the Late Jurassic and Cretaceous, increased dispersal potential might have been a key factor to explain the success of maniraptoran, and especially avialian theropods, with dispersal events being followed by endemic radiations of different clades.
Christian Foth and Oliver W. M. Rauhut. 2017. Re-evaluation of the Haarlem Archaeopteryx and the Radiation of Maniraptoran Theropod Dinosaurs. BMC Evolutionary Biology. 17:236. DOI: 10.1186/s12862-017-1076-y
Groot nieuws! De beroemde #Archaeopteryx van Teylers Museum blijkt nog ouder dan gedacht en wereldwijd uniek te zijn. Het is een fossiel van een nieuw ontdekte dinosaurussoort met veren, die de naam Ostromia heeft gekregen. #breakingnews http://bit.ly/2jdITeB@TEYLERS
Paleontologists at LMU correct a case of misinterpretation: The first fossil “Archaeopteryx” to be discovered is actually a predatory dinosaur belonging to the anchiornithid family, which was previously known only from finds made in China: http://www.en.uni-muenchen.de/news/newsarchiv/2017/rauhut_archaeopteryx.html … @LMU_Muenchen
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Earth’s lower latitudes boast the majority of extant avian species-level and higher-order diversity, with many deeply diverging clades restricted to vestiges of Gondwana. However, palaeontological analyses reveal that many avian crown clades with restricted extant distributions had stem group relatives in very different parts of the world.
Results:
Our phylogenetic analyses support the enigmatic fossil bird Foro panarium Olson 1992 from the early Eocene (Wasatchian) of Wyoming as a stem turaco (Neornithes: Pan-Musophagidae), a clade that is presently endemic to sub-Saharan Africa. Our analyses offer the first well-supported evidence for a stem musophagid (and therefore a useful fossil calibration for avian molecular divergence analyses), and reveal surprising new information on the early morphology and biogeography of this clade. Total-clade Musophagidae is identified as a potential participant in dispersal via the recently proposed ‘North American Gateway’ during the Palaeogene, and new biogeographic analyses illustrate the importance of the fossil record in revealing the complex historical biogeography of crown birds across geological timescales.
Conclusions:
In the Palaeogene, total-clade Musophagidae was distributed well outside the range of crown Musophagidae in the present day. This observation is consistent with similar biogeographic observations for numerous other modern bird clades, illustrating shortcomings of historical biogeographic analyses that do not incorporate information from the avian fossil record.
Fig. 1 Skeletal morphology of total clade musophagids. (a) Complete skeleton of Foro panarium holotype USNM 336261. Scale bar equals 10 cm. (b) 3-dimensional CT rendering of the pectoral region of Ross’s Turaco (Musophaga rossae) GCO 1142 (Georgia College Ornithology, Georgia College and State University, Milledgeville, GA). LF – left ramus of furcula, RC – right coracoid, RF – right ramus of furcula, S – sternum. 153:1 denotes unfused midline of furcula, which optimizes as an unambiguous synapomorphy of a Foro + Musophagidae clade. (c) Pectoral region of F. panarium. LH – left humerus, RS – right scapula. (d) Cranial region of USNM 336261. 50:1 processus costales of axis absent. 152:1 bill short and stout with broad processus maxillaris of the os nasale. (e) Distal end of right leg of USNM 336261. 109:0 – trochlea metatarsi IV without large trochlea accessoria. 106:0 tendon of musculus flexor hallucis longus not enclosed in bony canal
Daniel J. Field and Allison Y. Hsiang. 2018. A North American Stem Turaco, and the Complex Biogeographic History of Modern Birds. BMC Evolutionary Biology. 18:102. DOI: 10.1186/s12862-018-1212-3
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
For more than a century we have known that a high diversity of arthropod species lives in close relationship with army ant colonies. For instance, several hundred guest species have been described to be associated with the Neotropical army ant Eciton burchellii Westwood, 1842. Despite ongoing efforts to survey army ant guest diversity, it is evident that many more species await scientific discovery.
Results:
We conducted a large-scale community survey of Eciton-associated symbionts, combined with extensive DNA barcoding, which led to the discovery of numerous new species, among them a highly specialized histerid beetle, which is formally described here. Analyses of genitalic morphology with support of molecular characters revealed that the new species is a member of the genus Nymphister. We provide a literature review of host records and host-following mechanisms of Eciton-associated Haeteriinae demonstrating that the new species uses an unusual way of phoretic transport to track the nomadic habit of host ants. Using its long mandibles as gripping pliers, the beetle attaches between the ants’ petiole and postpetiole. The beetles specifically attach to medium-sized ant workers, thus participating as hitchhikers in the regular colony emigrations of the single host species Eciton mexicanum Roger, 1863.
Conclusion:
By providing tools for reliable species identification via morphology and DNA barcodes for hitherto unknown army ant guest species, we set the baseline for studies targeting the ecological and evolutionary dynamics in these species-rich host-symbiont communities.
Keywords: Phoresy, Social parasitism, Myrmecophile, Eciton, Host specificity, Nymphister, Army ants, Specialization, Symbiosis
Nymphister kronaueri
Etymology. We dedicate this species to Daniel Kronauer, an avid field biologist and long-time army ant researcher, who discovered the species during an Eciton mexicanum s. str. colony emigration.
Distribution. Known only from the type locality, i.e. La Selva Biological Station, a lowland Atlantic rainforest in Costa Rica.
Conclusions
Despite the enduring efforts to explore the microcosm of army ant-associated arthropods, a large proportion of unknown biodiversity still exists today. Myrmecophile communities of army ant species other than E. burchellii and E. hamatum have not been intensively studied, and thus it can be expected that many more species with fascinating adaptations still await scientific discovery. The present study is an example demonstrating the benefits of a combined approach, using morphology and DNA barcodes, to discover and describe new species in ant-myrmecophile communities.
Christoph von Beeren and Alexey K. Tishechkin. 2017. Nymphister kronaueri von Beeren & Tishechkin sp. nov., An Army Ant-associated Beetle Species (Coleoptera: Histeridae: Haeteriinae) with An Exceptional Mechanism of Phoresy. BMC Zoology. 2:3. DOI: 10.1186/s40850-016-0010-x
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
