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This synoptic review aims to bring some general information on fossil scorpions, namely those trapped in amber - fossilized resin - ranging from Lower Cretaceous through the Palaeocene and up to the Miocene. The question to be addressed is how the study of these fossils can be connected with possible present scorpionism problems. A precise knowledge of these ancient lineages provides information about the evolution of extant lineages, including the buthoids, which contain most known noxious species. Among the Arthropods found trapped in amber, scorpions are considered rare. A limited number of elements have been described from the Late Tertiary Dominican and Mexican amber, while the most ancient Tertiary amber from the Baltic region produced more consistent results in the last 30 years, primarily focusing on a single limited lineage. Contrarily, the Cretaceous amber from Myanmar, also called Burmite, has yielded and continues to yield a significant number of results represented by several distinct lineages, which attest to the considerable degree of diversity that existed in the Burmese amber-producing forests. As in my previous similar contributions to this journal, the content of this note is primarily addressed to non-specialists whose research embraces scorpions in various fields such as venom toxins and public health. An overview knowledge of at least some fossil lineages can eventually help to clarify why some extant elements associated with the buthoids represent dangerous species while others are not noxious.

RESUMEN

This synoptic review aims to bring some general information on fossil scorpions, namely those trapped in amber - fossilized resin - ranging from Lower Cretaceous through the Palaeocene and up to the Miocene. The question to be addressed is how the study of these fossils can be connected with possible present scorpionism problems. A precise knowledge of these ancient lineages provides information about the evolution of extant lineages, including the buthoids, which contain most known noxious species. Among the Arthropods found trapped in amber, scorpions are considered rare. A limited number of elements have been described from the Late Tertiary Dominican and Mexican amber, while the most ancient Tertiary amber from the Baltic region produced more consistent results in the last 30 years, primarily focusing on a single limited lineage. Contrarily, the Cretaceous amber from Myanmar, also called Burmite, has yielded and continues to yield a significant number of results represented by several distinct lineages, which attest to the considerable degree of diversity that existed in the Burmese amber-producing forests. As in my previous similar contributions to this journal, the content of this note is primarily addressed to non-specialists whose research embraces scorpions in various fields such as venom toxins and public health. An overview knowledge of at least some fossil lineages can eventually help to clarify why some extant elements associated with the buthoids represent dangerous species while others are not noxious.(AU)

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A new genus and species of the family Endomychidae (Coleoptera: Coccinelloidea): Cretostenotarsus striatus Tomaszewska, Szawaryn and Arriaga-Varela gen. et sp. nov. are described, diagnosed and illustrated from the mid-Cretaceous amber from northern Myanmar. To test the systematic placement of the new extinct genus and species within the family, a phylogenetic analysis was conducted. A dataset of 38 morphological characters scored for 29 species (including the new fossil taxon), members of Endomychidae sensu stricto and representatives of Coccinelloidea as outgroups were analyzed using maximum parsimony. The results of the analysis indicate unequivocally that Cretostenotarsus striatus is a member of the Stenotarsus clade within a monophyletic 'endomychine complex' sensu Robertson et al. (2015), which corresponds to 'Higher Endomychidae' sensu Tomaszewska (2005). The present discovery confirms at least the Jurassic origin of Coccinelloidea and indicates a much older origin of Endomychidae than previously hypothesized.

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BACKGROUND: During the Mesozoic, there were many insects in several holometabolous orders (Neuroptera, Mecoptera and Diptera) with elongated mouthparts adapted for feeding on nectar. The evolutionary history of the megadiverse order Coleptera, which has a great diversity of mouthparts and feeding strategies, is well documented since early Permian with a significant peak in diversity in the Triassic. Currently, however, there is no evidence that in the Mesozoic these beetles fed on nectar despite the recorded specializations for pollination of flowering plants in several families since the mid-Cretaceous. RESULTS: Here we describe a new wedge-shaped beetle Melanosiagon serraticornis gen. et sp. nov. from mid-Cretaceous Burmese amber attributed to Macrosiagonini (Ripiphoridae: Ripiphorinae), which has elongated galea comparable to that in the extant parasitoid genus Macrosiagon, and a well known example of adaptation for nectar feeding in Coleoptera. Furthermore, Salignacicola gen. nov. is established for Macrosiagon ebboi Perrichot, Nel et Néraudeau, 2004, based on the holotype found in mid-Cretaceous amber from France. Systematic positions of both newly established genera are discussed. A list of potential wasp and bee hosts of Ripiphorinae from the Mesozoic is provided. CONCLUSIONS: This study presents evidence of the earliest occurrence of specialized nectar feeding mouthparts in Coleoptera. Melanosiagon serraticornis is closely related to extant Macrosiagonini. In all genera belonging to subfamily Ripiphorinae the primary larvae are adapted for parasitism on aculeate Hymenoptera (bees and wasps) and adults are associated with blossoms of flowering plants, in terms of their specialized morphology. Adults of Macrosiagon visit blossoms of flowering plants to obtain nectar and lay eggs from which the hatching larvae attack visiting wasps and bees. An association with flowers of some tropical trees is already corroborated in some extant species. Interestingly the larvae of Ripiphorinae are also found in Burmese amber. Thus, both life stages of the mid-Cretaceous Ripiphorinae indicate a close association of this lineage with flowering trees.

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Oculudentavis khaungraae was described based on a tiny skull trapped in amber. The slender tapering rostrum with retracted narial openings, large eyes, and short vaulted braincase led to its identification as the smallest avian dinosaur on record, comparable to the smallest living hummingbirds. Despite its bird-like appearance, Oculudentavis showed several features inconsistent with its original phylogenetic placement. Here, we describe a more complete specimen that demonstrates Oculudentavis is actually a bizarre lizard of uncertain position. The new specimen is described as a new species within the genus Oculudentavis. The new interpretation and phylogenetic placement highlight a rare case of convergent evolution in skull proportions but apparently not in morphological characters. Our results re-affirm the importance of Myanmar amber in yielding unusual taxa from a forest ecosystem rarely represented in the fossil record.

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Attenuated Total Reflection (ATR) spectroscopy coupled with a microscope allows for the analysis of specimens without any preparation, spatially correlated with the morphology of the specimen. These characteristics make micro-ATR systems very useful for studying gemstones and in particular amber samples. Indeed, in this report, the micro-ATR technique was used to characterize three Burmite samples, as case studies. Particularly, focusing the ATR crystal spot on the amber surface where a difference in the Ultraviolet (UV) reaction was previously detected, thereby relative differences in the IR spectrum could be analyzed. Here we present a methodology combining the UV imaging technique with the micro-Attenuated total reflection Fourier transform infrared spectroscopy (micro-ATR/FT-IR) analyses, in order to correlate the fluorescence information with the molecular vibrational modes of amber and their relative spatial distribution. Finally, this work is intended as an initial methodology study and part of the amber characterization project, focused on characterizing the Burmese amber collection of the Peretti Museum Foundation from several disciplines (i.e., palaeoentomology, vibrational spectroscopy, neutron tomography, etc.).

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Rohrthripidae is a family of fossil thrips in the thysanopteran suborder Tubulifera. It includes a single genus, Rohrthrips, of which two species are previously known. Despite typical tubuliferan features, these thrips also show some terebrantian character states, particularly in the wings and antennae, and these are here interpreted as plesiomorphic. Five new species of these ancestral thrips are described from Burmese Cenomanian amber: Rohrthrips breviceps sp. n., Rohrthrips jiewenae sp. n., Rohrthrips maryae sp. n., Rohrthrips patrickmuelleri sp. n. and Rohrthrips schizovenatus sp. n.. Structures on the wings support the conclusion that the wings of Tubulifera are homologous with those of Terebrantia. Syninclusions in the amber fragments provide evidence of the diet and habitats of these ancestral thrips.

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A fossil genus Myanmaro gen. nov., with a species M. primus sp. nov. (Diptera, Chironomidae) is described from mid-Cretaceous Burmese amber (~100 Ma). The adult male of the new species shows the wing venation pattern lacking a cross-vein MCu, the fore leg ratio lower than 1, and the gonostylus folded inwards - features typical of the subfamily  Orthocladiinae. A bifid gonostylus, with an articulate, likely movable inner branch, is the character indicating a close relationship between Myanmaro and Diplocladius Kieffer, 1908, the latter genus previously postulated as an early lineage in Orthocladiinae. Several characters, i.e. the structure of tergite IX and the anal point, are defined as generic autapom orphies for Myanmaro. A combination of the shape of hypopygial volsellae (or their absence) and the lack of tibial combs also separate this genus from related extant Orthocladiinae and from the only known Cretaceous extinct orthoclad genus Lebanorthocladius Veltz, Azar et Nel, 2007.

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Concerning the description of Rohrthrips patrickmuelleri Ulitzka (2019), it has been brought to my attention that the depositary and serial number of the holotype was not given. This information is given below in order to comply with ICZN, Article 16.4.2 (1999).

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Two new genera and species of Coniopterygidae (Neuroptera) are described and illustrated from mid Cretaceous (Cenomanian) amber of Myanmar. Mulleroconishyalina gen. n. et sp. n., attributed to the Coniopteryginae, bears a unique combination of venation characters and an abdomen without plicatures. The second new genus, attributed to the Aleuropteryginae, i.e. Palaeoconisazari gen. n. et sp. n., displays a unique pattern of crossveins 1m-cua and 2mp2-cua, with the latter crossing the pigmented spot. A check-list of all fossil genera and species of Coniopterygidae is provided.

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Twisted winged insects (Strepsiptera) are a highly specialized small order of parasitic insects. Whether parasitism developed at an early or late stage in the evolution of the group was unknown. Here we record and describe the first definite Mesozoic strepsipteran primary larva embedded in Burmese amber (∼99 million years ago). This extends the origin of parasitism back by at least ∼50 million years, and reveals that this specialized life style has evolved in the Mesozoic or even earlier in the group. The extremely small first instar displays all diagnostic characters of strepsipteran immatures of this stage and is nearly identical with those of Mengenillidae, one of the most "ancestral" extant strepsipteran taxa. This demonstrates a remarkable evolutionary stasis over  100 million years. The new finding strongly weakens the case of small larvae embedded in Cretaceous amber interpreted as strepsipteran immatures. They differ in many structural features from extant strepsipteran primary larvae and are very likely parasitic beetle larvae.

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Burmite, a Cretaceous amber coming from the north of Myanmar, is known to preserve a great diversity of fossil arthropods, particularly insects. Many inclusions of different taxa in several insect orders have been well analysed, but this is the first study focussed on the Thysanoptera found in Burmite. In the sub-order Terebrantia, family Merothripidae, Myanmarothrips pankowskiorum gen. n., sp. n. is recognized in various amber samples from a total of 34 females but only one male. In the sub-order Tubulifera, Rohrthrips burmiticus sp. n. is based on a single female with a tubular tenth abdominal segment. This is an exceptionally well-preserved specimen, and details of the mouth parts indicate that the gnathal apparatus of modern Tubulifera was already developed in the Cretaceous. Due to plesiomorphic characters with respect to extant Tubulifera, the genus Rohrthrips is transferred to Rohrthripidae fam. n., and this family is clearly differentiated from extant Phlaeothripidae.

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A preliminary study on fossil scorpions found in amber, from the Lower Cretaceous through the Palaeocene and up to the Miocene is proposed. Scorpions remain rare among the arthropods found trapped in amber. Only 24 specimens are known from Cretaceous amber, representing eight families and subfamilies, ten genera and 21 species; in parallel, 10 specimens have been recorded from Baltic amber representing seven genera and ten species. A few more recent fossils from Dominican and Mexican amber have also been described. The present study of a new scorpion specimen from the Cretaceous amber of Myanmar (Burmite) resulted in the description of one new species, Betaburmesebuthus bellus sp. n. - belonging to the subfamily Palaeoburmesebuthinae Lourenço, 2015. The new description brings further elements to the clarification of the status of this subfamily, which is now raised to family level. Once again, this new Burmite element attests to the considerable degree of diversity in the Burmese amber-producing forests.