Salpinganthium hispaniolanum gen. et sp. nov. (Fabaceae: Detarieae), a mid-Tertiary flower in Dominican amber

Salpinganthium hispaniolanum gen. et sp. nov. is described as a new fossil legume from mid-Tertiary forests of Hispaniola. Arborescent legumes of tribe Detarieae previously described from these forests include Hymenaea protera and Prioria dominicana. Flowers of the new genus and species have a bilaterally symmetrical corol-la of five petals, 10 free stamens, an elongate, cylindrical hypanthium, and one or two persistent sepals, the others perhaps being deciduous. The petals are of three markedly different shapes. The pistil is exserted from the hypanthium and is densely hirsute. The bracteoles, sepals, and petals are gland-dotted, as is appropriate for members of the resin-producing Detarieae of subfamily Detarioideae.

An owlfly larva preserved in Mexican amber and the Miocene record of lacewing larvae

Neuroptera (lacewings) is today a rather small lineage of Holometabola. These representatives of Insecta have mostly predatory larvae with prominent venom-injecting stylets formed by upper and lower jaws. These impressive larvae can be found not only in the modern fauna, but sometimes also as fossils, predominantly preserved in amber. Here we report a new specimen of a lacewing larva from Miocene Mexican amber, most likely a larva of an owlfly (Ascalaphidae) with large prominent stylets, each with three teeth. These stylets arise from a more or less square-shaped head (in dorsal view) that has distinct eye hills with at least three simple eyes (stemmata) each. The trunk is rather short. Trunk segments possess finger-like protrusions carrying numerous setae, which could have been used to attach camouflaging debris to it. Remarkably, the specimen represents only the second report of a lacewing from Miocene Mexican amber, and the first larva. Additionally, we review the Miocene record of lacewing larvae. It includes otherwise only fossils preserved in Dominican amber and remains rather scarce, with only eight specimens in the literature so far. While there seem to be additional specimens in private collections, the overall number is astonishingly low compared to the numbers in Eocene and Cretaceous ambers. Ecological and taphonomic factors possibly explaining the rarity of lacewing larvae in Miocene amber are discussed here.

A tardigrade in Dominican amber

Tardigrades are a diverse group of charismatic microscopic invertebrates that are best known for their ability to survive extreme conditions. Despite their long evolutionary history and global distribution in both aquatic and terrestrial environments, the tardigrade fossil record is exceedingly sparse. Molecular clocks estimate that tardigrades diverged from other panarthropod lineages before the Cambrian, but only two definitive crown-group representatives have been described to date, both from Cretaceous fossil deposits in North America. Here, we report a third fossil tardigrade from Miocene age Dominican amber. Paradoryphoribius chronocaribbeus gen. et sp. nov. is the first unambiguous fossil representative of the diverse superfamily Isohypsibioidea, as well as the first tardigrade fossil described from the Cenozoic. We propose that the patchy tardigrade fossil record can be explained by the preferential preservation of these microinvertebrates as amber inclusions, coupled with the scarcity of fossiliferous amber deposits before the Cretaceous.

A new biting midge of the genus Forcipomyia Meigen, 1818 from Miocene Ethiopian amber (Diptera: Ceratopogonidae)

Biting midges (Ceratopogonidae) are a relatively well-studied family of nematocerous flies distributed worldwide, including 6,206 extant and 296 fossil species. To date, 1,146 extant and 32 fossil species in the genus Forcipomyia have been recorded in the world (Borkent & Dominiak, 2020). Biting midges of the subgenus Forcipomyia s. str. are indicative of forests because their larvae and pupae usually live under the bark of rotting trees (Szadziewski, 2018). The oldest records of the genus are from the Eocene. Forcipomyia are reported from early Eocene Fushun amber (one species; Hong, 1981; Stebner et al., 2016; Szadziewski, 2018; Krzemiński et al., 2019), early Eocene Cambay amber (unnamed, Stebner et al., 2017), middle Eocene Sakhalin amber (one species, Szadziewski & Sontag, 2013), Eocene Baltic amber from the Gulf of Gdańsk, Rovno and Bitterfeld (21 species; Szadziewski, 1988, Szadziewski, 1993, Sontag & Szadziewski, 2011), Miocene Dominican amber (10 species, Szadziewski & Grogan, 1998) and Miocene Mexican amber (unnamed, Szadziewski & Grogan, 1996).

The study of Dominican amber-bearing sediments from Siete Cañadas and La Cumbre with a discussion on their origin

The paper presents comprehensive mineralogical and geochemical characteristics of Dominican amber-bearing sediments from Siete Cañadas, Hato Mayor Province of the Eastern Mining District (EMD) in the Cordillera Oriental. The characteristics of rocks collected from the borehole in Siete Cañadas area (EMD) were compared with petrography of coaly shales from La Cumbre in the Northern Mining District (NMD). The mineralogy of the rocks was determined using transmitted and reflected light microscopy, scanning electron microscopy, Powder X-ray diffraction and Fourier Transform Raman Spectroscopy. Biomarker analyses by the gas chromatography–mass spectrometry were used to trace the genetic source and transformation stage of organic matter hosted in the core sediments. In this study, the characteristics of rocks from La Cumbre were supplemented with the petrographic data from our studies reported earlier. Based on the findings, it has been concluded that the basins in the investigated parts of the EMD and NMD regions were likely characterized by different, isolated palaeosettings. Transformation and maturation of terrigenous material were affected by locally occurring physicochemical conditions. In both amber deposits, the sedimentation of clastic and organic material proceeded in the presence of marine conditions. In case of the La Cumbre deposit (NMD area), the sedimentation underwent probably in the conditions of the lagoon environment, a shallow maritime lake or periodically flooded plain that facilitated organic matter decomposition and carbonation from meta-lignite to sub-bituminous coal (random reflectance of coal—Rro = 0.39%). In the Siete Cañadas (EMD region), the sedimentation took place in a shallow saltwater basin, where terrigenous material was likely mixed with material found in situ (fauna fossils, carbonate-group minerals) to form the mudstones enriched in bituminous substance of low maturity. The organic matter found in the rocks from both deposits is of mixed terrestrial/marine origin and was deposited in the presence of low oxygen concentration and reducing and/or dysoxic conditions.

The polycentropodid genus <i>Cernotina</i> (Insecta, Trichoptera) in Miocene Dominican amber

A new polycentropodid caddisfly species is described from Miocene Dominican amber. The family Polycentropodidae is therefore represented in the Dominican amber with two species belonging to the genus Cernotina: C. pulchra Wichard, 2007, and C. fossilinova sp. nov. The endemic C. danieli Flint &amp; Sykora, 2004, is the only representative of the genus occurring on Hispaniola today and is similar to the two fossil species. On the Caribbean islands altogether six extant species of the genus Cernotina are registered.

A parasitic coevolution since the Miocene revealed by phase-contrast synchrotron X-ray microtomography and the study of natural history collections

The discovery of a new fossil species of the Caribbeo-Mexican genus Proptomaphaginus (Coleoptera, Leiodidae, Cholevinae) from Dominican amber, associated with a new fossil parasitic fungus in the genus Columnomyces (Ascomycota, Laboulbeniales), triggered an investigation of extant species of Proptomaphaginus and revealed the long-enduring parasitic association between these two genera. This effort resulted in the description of the fossil species †Proptomaphaginus alleni sp. nov., and one fossil and two extant species of Columnomyces, selectively associated with species of Proptomaphaginus: †Columnomyces electri sp. nov. associated with the fossil †Proptomaphaginus alleni in Dominican amber, Columnomyces hispaniolensis sp. nov. with the extant Proptomaphaginus hispaniolensis (endemic of Hispaniola), and Columnomyces peckii sp. nov. with the extant Proptomaphaginus puertoricensis (endemic of Puerto Rico). Based on biogeography, our current understanding is that the Caribbean species of Proptomaphaginus and their parasitic species of Columnomyces have coevolved since the Miocene. This is the first occurrence of such a coevolution between a genus of parasitic fungus and a genus of Coleoptera. The phylogenetic relations among Proptomaphaginus species are also addressed based on a parsimony analysis. Fossil specimens were observed by propagation phase-contrast synchrotron X-ray microtomography (PPC-SRμCT) and extant specimens were obtained through the study of preserved dried, pinned insects, attesting for the importance of (i) technological advancement and (ii) natural history collections in the study of microparasitic relationships.