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Dinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here, we describe the amber from the Lower Cretaceous dinosaur bonebed of Ariño (Teruel, Spain) using a multidisciplinary approach. Amber is found in both a root layer with amber strictly in situ and a litter layer mainly composed of aerial pieces unusually rich in bioinclusions, encompassing 11 insect orders, arachnids, and a few plant and vertebrate remains, including a feather. Additional palaeontological data-charophytes, palynomorphs, ostracods- are provided. Ariño arguably represents the most prolific and palaeobiologically diverse locality in which fossiliferous amber and a dinosaur bonebed have been found in association, and the only one known where the vast majority of the palaeontological assemblage suffered no or low-grade pre-burial transport. This has unlocked unprecedentedly complete and reliable palaeoecological data out of two complementary windows of preservation-the bonebed and the amber-from the same site., Competing Interests: SÁ, RP, EP, EB, LA, JP, CM, KT, NM, RL, RL, DP, AR, VS, CB, CM, MP, AS, CP, AA, EE, LM, XD No competing interests declared, (© 2021, Álvarez-Parra et al.)

Echinochara is a poorly known charophyte genus of the extinct family Clavatoraceae that thrived in the Middle Jurassic–Early Cretaceous of North America, Europe, and North Africa. It represents the most ancient and plesiomorphic genus of this family. However, the fossil record of Echinochara is discontinuous, showing several gaps, one of them especially significant in evolutionary terms between the Kimmeridgian and the early Barremian. The new species Echinochara pontis sp. nov., described here from the late Berriasian of the Maestrat Basin (NE Spain), bridges, in part, this gap, shedding light on the evolution of the genus during the earliest Cretaceous. The fructification (utricle) has bilateral symmetry, formed by two superimposed series of bract cells that abaxially cover the gyrogonite. The inner series has three long cells that are born by a short basal cell and reach the oospore apex. The outer series shows a central fan of bract cells, composed of a small basal cell, triangular in shape, that bears three long cells growing upwards, which are in turn flanked by two long bract cells on each side. The central basal cell and these two lateral cells are directly attached to the base of the utricle. The thallus is corticated with cells twisting at an angle of 30°. The utricle of Echinochara pontis displays a combination of features present in Echinochara peckii (Bathonian?–Kimmeridgian) and Echinochara lazarii (Barremian–early Aptian). For instance, the bilateral symmetry of the utricle and the morphology of the inner bract-cell series allow comparison with E. lazarii , whilst the morphology of the outer bract-cell series is closer to E. peckii. Moreover, the thallus of the new species shows cortical cells with a twisting angle intermediate between that of Echinochara peckii (40°–45°) and Echinochara lazarii (not twisted). The unique combination of morphological characters in the utricle of Echinochara pontis fits well with its intermediate chronostratigraphic position between the two former species. Echinochara pontis formed monospecific meadows in brackish settings. A preference for brackish settings is also observed for Echinochara peckii and in the older populations of Echinochara lazarii , suggesting that this habitat is probably a basal character in the evolution of the genus Echinochara. • Echinochara pontis sp. nov. is described from the late Berriasian of Iberia. • The new species covers a gap of 23 My in the fossil record of Echinochara. • The utricle has bilateral symmetry like a more derived Barremian species. • The external series shows trifurcations like the more plesiomorphic species. • Echinochara pontis sp. nov. formed monospecific meadows in brackish settings. [ABSTRACT FROM AUTHOR]

Palaeonitella trifurcata n. sp. is a minute ecorticate thallus of a charophyte from a non-marine upper Barremian–Lower Aptian section of the Garraf Massif, near Barcelona (Catalonia, Spain). Whorls of trifurcated branchlets built glomerules about 1 mm across. Small radial branchlets were trifurcated once in three terminal acuminate dactyls. Longer and more robust branches, two per whorl emerge from a basal trifurcation, bore opposite secondary branchlets and ended in three terminal branchlets bearing one oospore. The whole set of characters suggests affinity with Nitella , making of this fossil one of the oldest and unique possible records of thalli of this extant genus. The thallus of P. trifurcata n. sp. was encrusted by a thin micrite film, and additionally, the whorls were coated by a thicker crust while the plant was still alive. It is suggested that this crust was formed upon the periphyton which grew perhaps upon a mucilage covering the whorls and apical heads, as it happens in extant Nitella. After encrustation, a small (ca. 5 mm across) constructive micrite envelope, called a cortoid, was formed attached to the plant, preserving in the inside the thallus articulated and slightly encrusted. Once the plant died, such cortoids accumulated on the lake bottom and were buried and lithified, forming a "cortolite". This is the first report of constructive micrite envelopes protecting delicate and poorly calcified charophyte thalli from being destroyed. • The first fossil charophyte thallus with strong affinities to extant Nitella is reconstructed. • The fossil record of this type of thallus is exceptional since it rarely calcifies. • Portions of thalli occur calcified within coated grains in a Lower Cretaceous limestone near Barcelona. • Such coated grains, called cortoids, formed while the plant was still alive. • The new term "cortolite" is proposed for the rock texture produced by the accumulation of cortoids. [ABSTRACT FROM AUTHOR]