Cretaceous Research最新文献

The microsporangiate cone Classostrobus amealensis sp. nov. with in situ pollen from the Lower Cretaceous (lower Hauterivian) of Portugal: pollen ultrastructure and implications for frenelopsid species diversity 葡萄牙下白垩世（下Hauterivian）微孢子球果Classostrobus amealensis sp. 11 .的原位花粉：花粉超微结构及其对长翅纲物种多样性的影响

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2026-01-14 DOI: 10.1016/j.cretres.2026.106315

Maria Tekleva , Mário Miguel Mendes , Jiří Kvaček , Johanna H.A. Van Konijnenburg-van Cittert , Pedro Miguel Callapez , Zuzana Heřmanová

A new cheirolepidiaceous conifer pollen cone, Classostrobus amealensis sp. nov., is described from the Lower Cretaceous of Lusitanian Basin, in the Estremadura region of western Portugal. The new microsporangiate cone was collected in the Vale Cortiço open cast clay pit complex, near the small village of Ameal, from sedimentary deposits belonging to Santa Susana Formation and considered to be early Hauterivian in age. The new species is based on a single well-preserved, coalified microsporangiate cone, ca. 27 mm long and 14 mm wide, ovoid in shape, bearing ca. 20 helically arranged, imbricate microsporophylls. The microsporophyll bears four pollen sacs abaxially and it is smooth or finely papillate showing an acute apex fringed with short trichomes. The new microsporangiate cone is morphologically different from all Classostrobus species previously described, and we compare it with all other frenelopsid microsporangiate cones known to date. Pollen grains in situ show close similarity to dispersed pollen of the species Classopollis martinottii Reyre, 1970. Pollen details were studied using LM as well as scanning electron (SEM) and transmission electron microscopy (TEM). Pollen grains are spheroidal, ca. 26.1 μm in LM and 23.8 μm in SEM, characterized by an equatorial band with six to eight striations, a distal cryptopore, and a proximal tetrad scar. The exine sculpture is distinctly microechinate. The new microsporangiate cone is associated with fragments of vegetative shoots of Frenelopsis teixeirae Alvin et Pais 1978 and Pseudofrenelopsis dinisii M.M.Mendes et J.Kvaček et al., 2023.

在葡萄牙西部埃斯特雷马杜拉地区的卢西塔尼亚盆地下白垩世发现了一种新的针叶科针叶树花粉球果Classostrobus amealensis sp. nov.。新的微孢子体圆锥体是在靠近Ameal小村庄的Vale cortirado露天粘土坑群中收集到的，来自于属于Santa Susana组的沉积矿床，被认为是早Hauterivian时代。新种是基于一个保存完好的，联合的小孢子囊球果，长约27毫米，宽约14毫米，卵球形，长约20个螺旋排列的，叠瓦状的小孢子叶。小孢子叶背面有4个花粉囊，光滑或细乳头状，尖尖具短毛。新发现的小孢子囊球果在形态上不同于以前所描述的所有类球，我们将其与迄今为止已知的所有系蛙类小孢子囊球果进行了比较。原位花粉粒与Classopollis martinottii Reyre， 1970的分散花粉相似。利用LM、扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了花粉的细节。花粉粒呈球形，LM约26.1 μm， SEM约23.8 μm，具有6 ~ 8条条纹的赤道带，远端为隐孔，近端为四分体疤痕。外面的雕塑明显是微尖形的。新的小孢子球果与Frenelopsis teixeirae Alvin et Pais 1978和Pseudofrenelopsis dinisii m.m.d endes et j.k vaek et al.， 2023的营养芽片段有关。

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引用次数: 0

An actinopterygian-dominated fish fauna from the Upper Cretaceous Williams Fork Formation, northwestern Colorado, and evidence for provinciality across Laramidia at the Campanian/Maastrichtian boundary 科罗拉多西北部上白垩世Williams Fork组放光翼类为主的鱼类区系，以及在Campanian/Maastrichtian边界横跨Laramidia的证据

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2026-01-13 DOI: 10.1016/j.cretres.2026.106313

Joel Crothers , Jaelyn Eberle , Donald Brinkman , Alyssa Wurtz , Andrew B. Heckert , ReBecca K. Hunt-Foster , John R. Foster , Ida C. Dirkes , Renee Dunn

The Williams Fork Formation (WFF) of northwestern Colorado preserves an understudied freshwater biota from the Campanian/Maastrichtian boundary. Here we describe a diverse actinopterygian-dominated fish assemblage from the ReBecca's Hollow locality of Rio Blanco County. Chondrichthyans are rare from this site, but include a hybodontid, Lonchidion, and the hemiscyllid Chiloscyllium. A fragmentary element may represent a pycnodontiform. Chondrosteans are represented by a tentative acipenserid. Holosteans include the lepisosteids Atractosteus and an unnamed taxon, and the amiids Melvius, Cyclurus and Palaeolabrus. Teleosteomorphs at this site include Belonostomus, Paralbula casei, Coriops, Estesesox foxi, Acronichthys, hiodontids, and acanthomorphs. This locality yields at least 17 fish taxa, most of which have not been described previously from the WFF. Although the WFF is temporally correlative with the St. Mary River and Horseshoe Canyon Formations in Alberta and the Prince Creek Formation in Alaska, the ReBecca's Hollow fish assemblage is markedly different from its northern contemporaries. Specifically, it contains several warm-climate taxa such as Lonchidion, Chiloscyllium, Melvius, Atractosteus, and Paralbula, and lacks higher latitude taxa such as Holostean A, documented from Alberta. The differences in these broadly contemporaneous fish assemblages supports the hypothesis that there was provincialism amongst freshwater fishes in Laramidia at the Campanian/Maastrichtian boundary. The fish fauna thus resembles that of Campanian localities in Utah, New Mexico, and Texas, and Maastrichtian (Lancian) localities in Montana, North Dakota, South Dakota, and Wyoming, suggesting that the boundary between these provincial zones remained north of the WFF locality throughout these periods of climate change.

科罗拉多州西北部的威廉姆斯福克组（WFF）保存了一种未被充分研究的来自坎帕尼亚/马斯特里赫特边界的淡水生物群。在这里，我们描述了一个多样化的放线鱼为主的鱼类组合从里约热内卢布兰科县的丽贝卡山谷的地方。软骨鱼在这一地点很少见，但包括一种下颌骨、Lonchidion和半圆柱体的Chiloscyllium。一个片断的元素可能代表一个幻齿状体。软骨动物以一种暂定的鱼尾纲为代表。全骨类包括瘦异steids Atractosteus和一个未命名的分类单元，以及类群Melvius， Cyclurus和Palaeolabrus。该地点的远骨形态包括Belonostomus、parbula casei、Coriops、Estesesox foxi、Acronichthys、hiodontids和acanthomorphs。这个地方至少有17个鱼类分类群，其中大多数以前没有在WFF中被描述过。虽然WFF在时间上与阿尔伯塔省的圣玛丽河和马蹄峡谷地层以及阿拉斯加的王子溪地层相关，但丽贝卡山谷的鱼类组合与北部同时代的鱼类明显不同。具体来说，它包含几个温暖气候的分类群，如Lonchidion、Chiloscyllium、Melvius、Atractosteus和pallbula，而缺乏高纬度的分类群，如阿尔伯塔省记录的Holostean A。这些大致同一时期的鱼类组合的差异支持了在坎帕尼亚/马斯特里赫特边界的Laramidia淡水鱼中存在地方性的假设。因此，鱼类动物群类似于犹他州、新墨西哥州和德克萨斯州的坎帕尼亚地区，以及蒙大拿州、北达科他州、南达科他州和怀俄明州的马斯特里赫特（兰西亚）地区，这表明在这些气候变化时期，这些省级区域之间的边界一直保持在WFF地区的北部。

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引用次数: 0

Marine incursion in the lower Cretaceous Sanfranciscana Basin evidenced by ichnological data 下白垩世Sanfranciscana盆地海相入侵的技术证据

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2026-01-10 DOI: 10.1016/j.cretres.2026.106312

Daniel Sedorko

The Lower Cretaceous deposits of the Sanfranciscana Basin (Brazil) were predominantly shaped by continental processes. Despite this, thin chert layers bearing marine microfossils indicate brief marine incursions. Various hypotheses have been proposed to explain these fossils, ranging from storm-induced remobilization to episodic incursions controlled by faulting. The short-lived nature of these events has been suggested by the absence of sedimentological and ichnological evidence of sustained marine influence in the basin's interior. To explore whether these incursions left additional evidence beyond microfossil assemblages, this study integrates ichnological and sedimentological analyses in the southern Sanfranciscana Basin. Fieldwork focused on the transitional interval between the Quiricó and Três Barras formations. Notably, three sections within the basal Três Barras Formation preserve a marine ichnoassemblage, consisting of whitish, fine-grained stratified sandstones, with horizontally concentric-filled (Asterosoma), plug-shaped (Bergaueria), and spreiten-bearing (Teichichnus) burrows. The low-diversity ichnoassemblage suggests impacted salinity conditions, corresponding to a polyhaline-brackish setting. The studied successions show dominance of low angle stratified sandstone interbedded with trough cross-bedded sandstones and wave ripples, suggesting high energetic settings, locally reworked by waves. However, restricted exposition area and thickness, as well as low diverse marine signatures allow to identify a marine connection to the sea, precluding definition of an architectural element or depositional scenario. This record suggests that the marine incursions were long enough to allow benthic colonization of the substrate, as evidenced by at least 12 bioturbated beds. This data argues against episodic, short-lived colonization driven by storm events, at least for the here studied sections.

巴西Sanfranciscana盆地的下白垩统沉积主要由陆相作用形成。尽管如此，含有海洋微化石的薄燧石层表明短暂的海洋入侵。人们提出了各种各样的假说来解释这些化石，从风暴引起的迁移到由断层控制的幕式入侵。由于没有沉积学和技术证据表明盆地内部有持续的海洋影响，这些事件的短暂性表明。为了探索这些入侵是否在微化石组合之外留下了额外的证据，本研究综合了旧金山盆地南部的技术和沉积学分析。现场工作的重点是Quiricó和Três Barras组之间的过渡段。值得注意的是，在基底Três Barras组的三个剖面中保存了一个海洋生物组合，由白色、细粒的层状砂岩组成，具有水平同心填充（Asterosoma）、塞状（Bergaueria）和含spreiten （Teichichnus）的洞穴。低多样性的鱼类组合表明受影响的盐度条件，对应于多盐-半咸淡环境。研究的层序以低角度层状砂岩为主，与槽状交错层状砂岩和波浪纹互层，表明高能量环境，局部受到波浪的改造。然而，有限的展示面积和厚度，以及低多样性的海洋特征允许识别海洋与海洋的联系，排除了建筑元素或沉积场景的定义。这一记录表明，海洋入侵的时间足够长，足以让底栖生物在基质上定居，至少有12个生物扰动床证明了这一点。这些数据反对由风暴事件驱动的间歇性、短暂的殖民，至少对这里研究的部分来说是这样。

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引用次数: 0

Integrated astrochronology, isotope and biostratigraphy of the Albian-Cenomanian transition and expression of the OAE 1d in an expanded record of a rapidly subsiding Tethyan synorogenic basin (Core Jásd-42, Transdanubian range, Hungary) 快速沉降特提斯同造盆地扩展记录中Albian-Cenomanian过渡的综合天文年代学、同位素和生物地表学及OAE 1d的表达（核心Jásd-42，跨多瑙河山脉，匈牙利）

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2026-01-07 DOI: 10.1016/j.cretres.2025.106311

Zsolt Vallner , Tamás Müller , Dávid Bajnai , Ottilia Szives , Lajos Ádám Csicsek , Gábor Héja , Bernát Heszler , Norbert Zajzon , József Pálfy

The OAE 1d is one of the oceanic anoxic events that punctuate the Cretaceous and represent Earth system-wide changes prominently captured by carbon isotope excursions (CIE). Although the positive CIE near the Albian/Cenomanian boundary (ACB) is known from multiple localities, many of these records disagree in the shape of the δ¹³C curve. Interpretations of OAE 1d and a broader ACB Event (ACBE) remain ambiguous, and their duration is insufficiently constrained. Here we present new analyses on high-resolution samples from Core Jásd-42. The >450 m thick Pénzeskút Marl Fm. provides an expanded record across the ACBE. We generated elemental and stable isotope geochemical data and used these time series for cyclostratigraphic analyses. The derived astrochronologic age model establishes a depositional duration of 4.4–4.83 Myr and is integrated with ammonite and planktonic foraminifera biostratigraphy. This high-resolution chemostratigraphy provides a new, calibrated record of OAE 1d and the ACBE that we correlate with other reference sections, including the GSSP. A minimum estimate of 1.23 Myr and 2.28 Myr is obtained for OAE 1d and the ACBE, respectively. For the latter, a minimum of 602 kyr is assigned to the rising limb, 748 kyr to the culminating interval, and 931 kyr to the falling limb in the δ¹³C_carb curve. The δ¹³C record through OAE 1d appears orbitally controlled, where the positive peaks are paced by long eccentricity. Considering the differences between seasonality extremes, we suggest a model for depositional cyclicity in a synorogenic basin with a high sedimentation rate of 9–15 cm/kyr.

OAE 1d是白垩纪期间的海洋缺氧事件之一，代表了由碳同位素漂移（CIE）显著捕获的地球系统范围的变化。虽然在Albian/Cenomanian边界（ACB）附近的正CIE从多个位置已知，但这些记录中的许多δ13C曲线的形状不一致。对OAE 1d和更广泛的ACB事件（ACBE）的解释仍然不明确，它们的持续时间也没有足够的限制。在这里，我们对来自核心Jásd-42的高分辨率样本进行了新的分析。450米厚Pénzeskút沼泽Fm。提供跨ACBE的扩展记录。我们生成了元素和稳定同位素地球化学数据，并使用这些时间序列进行旋回地层分析。建立的星象年代学模型建立了4.4 ~ 4.83 Myr的沉积时间，并结合了鹦鹉螺和浮游有孔虫生物地层。这种高分辨率的化学地层学提供了一种新的、校准的OAE 1d和ACBE记录，我们将其与其他参考剖面（包括GSSP）相关联。OAE 1d和ACBE的最小估计值分别为1.23和2.28马币。对于后者，δ13Ccarb曲线上升段最小值为602 kyr，峰值段最小值为748 kyr，下降段最小值为931 kyr。通过OAE 1d的δ13C记录显示出轨道控制，其中正峰以长偏心率为节奏。考虑到季节极值之间的差异，我们提出了一个高沉积速率为9-15 cm/kyr的同造盆地沉积旋回模型。

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引用次数: 0

Upper Cretaceous flora of the Gosau Group of Kainach, Styria, Austria 奥地利施蒂里亚Kainach地区Gosau群的上白垩纪植物区系

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2025-12-31 DOI: 10.1016/j.cretres.2025.106310

Jiří Kvaček , Fritz Messner , Franz Bernhard

Upper Cretaceous flora (upper Santonian - lower Campanian) is described from the Kainach Gosau Group sediments in Styria, Austria, in the Central Eastern Alps. The flora is associated with thin coal seams. It consists of angiosperms dominated by monocotyledon foliage Pandanites trinervis, which is typical for coal-bearing strata of Gosau. The second most abundant angiosperm foliage in the locality of Geistthal is platanoid foliage Ettingshausenia geistthalensis sp. nov. Twelve dicotyledon leaves are described from the area of Kainach Gosau, including three new species Juglandiphyllites kainachensis sp. nov., J. graefii sp. nov. and J. roemaskogelensis sp. nov. Ferns and conifers (Geinitzia reichenbachii) are present, but in a distinct minority. The preserved flora is interpreted as vegetation of three types: 1) alluvial plain vegetation dominated by platanoids, 2) coal swamp vegetation dominated by pandanoids, 3) upland vegetation dominated by probable juglandoids. The terrestrial vegetation grew on the tectonically driven orogenic island, a part of the Adriatic Plate, in the northern part of the Tethys Sea. The massive occurrence of the Pandanites monocot is important not only as a palaeoecological indicator, but also for phytogeographical interpretations. As a thermophilous plant, it was tectonically delivered from the African coast to the southern coast of Europe by tectonic plate movement.

在阿尔卑斯山中东部奥地利施蒂里亚的Kainach Gosau群沉积物中描述了上白垩纪植物区系（上圣东纪-下坎帕纪）。该植物群与薄煤层有关。它由被子植物组成，以单子叶叶的三棱蕨为主，是戈索煤系地层的典型植物。盖斯塔地区第二丰富的被子植物叶片是平叶类植物Ettingshausenia geistthalensis sp. 11 . 11 .在盖纳奇古索地区发现了12片双子叶，包括3个新种Juglandiphyllites kainachensis sp. nov.、J. graefii sp. nov.和J. roemaskogelensis sp. 11 . 11 .蕨类植物和针叶树（Geinitzia reichenbachii），但明显占少数。保存的植物区系可划分为3种植被类型：1)以高原类植物为主的冲积平原植被，2)以熊猫类植物为主的煤沼泽植被，3)以可能的核桃类植物为主的高地植被。陆地植被生长在构造驱动的造山岛上，是亚得里亚海板块的一部分，位于特提斯海北部。单斑岩的大量出现不仅是一个重要的古生态指标，而且对植物地理解释具有重要意义。作为一种嗜热植物，它是通过构造板块运动从非洲海岸转移到欧洲南部海岸的。

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引用次数: 0

A new upper Cretaceous bramble shark from central Chile reveals austral diversity among Weddellian echinorhinids 在智利中部发现的一种新发现的上白垩纪黑刺鲨揭示了威德尔棘爪类动物在南方的多样性

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2025-12-31 DOI: 10.1016/j.cretres.2025.106309

Rodrigo A. Otero , Sergio Soto-Acuña , Raúl Ugalde , Patricio Sepúlveda , Alexander O. Vargas , Guillermo Aguirrezabala , Héctor Ortiz

Teeth of bramble sharks (Echinorhinidae) are one of the scarcest chondrichthyan elements reported to date in the Upper Cretaceous of central Chile and in general, South America. Prior to this research, its local record was restricted to only four available specimens, previously considered to be equivalent to teeth from the upper Maastrichtian of Argentinean Patagonia, being these referred to the species Echinorhinus maremagnum. This contribution presents two new elements, including the first complete large tooth from central Chile, showing the presence of a distally projected basal cusplet and a complex mesial, serrated cutting edge with the primordium of two clear cusplets, this last being a trait commonly present in several Cenozoic species. These new features remained unnoticed in the previous material from central Chile, either due to informative portions missing or the immature growth stage of the smaller known sample. The dental features of the new specimen are unique among known species of the genus Echinorhinus; moreover, the crown traits represent an ancestral condition with respect to those features commonly present in Cenozoic species. With the new evidence, all the known Echinorhinus teeth from the lower Maastrichtian of central Chile are now referred to Echinorhinus taverai sp. nov. The occurrence of the studied material directly associated with an elasmosaur skeleton is consistent with other findings of the genus in the Southern Hemisphere, suggesting that Upper Cretaceous austral Echinorhinus spp. were opportunistic scavengers in the shallow coastal waters of southern South America.

刺鲨的牙齿是迄今为止在智利中部和南美洲的上白垩纪报道的最稀有的软骨鱼类元素之一。在这项研究之前，它的当地记录仅限于四个可用的标本，以前被认为相当于阿根廷巴塔哥尼亚上马斯特里赫特人的牙齿，因为这些被称为棘猴。这一贡献提供了两个新的元素，包括来自智利中部的第一颗完整的大牙齿，显示出一个远端突出的基齿和一个复杂的中端锯齿状切削刃，其原始基具两个清晰的齿，这是几个新生代物种中普遍存在的特征。这些新特征在先前来自智利中部的材料中没有被注意到，要么是由于信息部分缺失，要么是由于较小的已知样本的未成熟生长阶段。新标本的牙齿特征在已知棘猴属物种中是独一无二的；此外，相对于那些在新生代物种中普遍存在的特征，冠状特征代表了一种祖先的条件。有了新的证据，在智利中部马斯特里赫特地区的下马斯特里赫特地区发现的所有已知的棘龙牙齿现在都被归为棘龙（echinhinus taverai sp. 11 .）。与依拉丝龙骨架直接相关的研究材料的出现与南半球该属的其他发现一致，这表明上白垩世南方棘龙是南美洲南部浅海水域的机会主义食腐动物。

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引用次数: 0

Late Albian floras of eastern Iberia: Insights into the palaeoenvironments and palaeoecology of fossil plant communities associated with amber-bearing sedimentary successions 伊比利亚东部的晚阿尔巴尼亚植物群：与含琥珀沉积演替有关的化石植物群落的古环境和古生态的见解

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2025-12-27 DOI: 10.1016/j.cretres.2025.106308

Carlos A. Bueno-Cebollada , Jiří Kvaček , Eduardo Barrón

Late Albian floras from eastern Iberia are mainly dominated by conifers with xeromorphic adaptations and include well-diversified fern and angiosperm communities. Some of these coniferous taxa are believed to be related to a global mass resin production period known as the Cretaceous Resin Interval (CREI), which ultimately led to the development of amber sites.

This research presents a study of late Albian macro- and mesofloras of eastern Iberia from descriptive, palaeoecological, and palaeoclimatological perspectives. The studied material was collected from four outcrops: the Cañada del Hoyo outcrop, located in the Cuenca Basin; and the Arroyo de la Pascueta, Cortes de Arenoso, and San Just outcrops, located in the Maestrazgo Basin. The collected taxa were grouped into four palaeoecological associations (PA-1 to PA-4), representing different biocoenoses from the coastline to the hinterland: Supra-to intertidal vegetal communities (PA-1), Nearshore woodlands with Araucariaceae (PA-2), Drought-adapted hinterland vegetation (PA-3), and Local riparian vegetal communities (PA-4). The dominance of taxa assigned to the genera Frenelopsis, Dammarites, and Eretmophyllum indicates that most of the assemblages are related to supratidal plant communities, a typical feature of the mid-Cretaceous Tethyan coast.

Furthermore, we reinforce the hypothesis of an Araucariaceae affinity for some of the upper Albian amber of the Maestrazgo Basin based on the presence of Brachyphyllum cf. obesum Heer (1881) and Rabagostrobus cf. hispanicus Kvaček et al. (2018). We also relate the lack of upper Albian amber-bearing strata in the Cuenca Basin to the sedimentary environment dynamics rather than to the nature of the palaeobotanical assemblages.

来自伊比利亚东部的晚阿尔巴尼亚植物区系主要以适应旱形的针叶树为主，包括多样化的蕨类和被子植物群落。其中一些针叶分类群被认为与白垩纪树脂间隔（CREI）的全球大规模树脂生产时期有关，该时期最终导致了琥珀遗址的发展。本研究从描述、古生态和古气候学的角度对伊比利亚东部的晚阿尔巴尼亚宏观和中型植物区系进行了研究。研究材料收集自四个露头：位于昆卡盆地的Cañada del Hoyo露头；以及位于Maestrazgo盆地的Arroyo de la Pascueta、Cortes de arennoso和San Just露头。将收集到的分类群划分为4个古生态群落（PA-1 ~ PA-4），代表了从海岸线到内陆不同的生物群落：超潮至潮间带植被群落（PA-1）、近岸带龙葵科林地（PA-2）、适应干旱的内陆植被群落（PA-3）和当地河岸植被群落（PA-4）。其中，Frenelopsis属、Dammarites属和Eretmophyllum属占主导地位，表明大多数组合与潮上植物群落有关，这是中白垩世特提斯海岸的典型特征。此外，基于Brachyphyllum cf. obesum Heer（1881）和Rabagostrobus cf. hispanicus kva eket al.（2018）的存在，我们加强了Araucariaceae与Maestrazgo盆地上部Albian琥珀的亲和性假设。我们还将昆卡盆地上亚系琥珀地层的缺乏与沉积环境动力学联系起来，而不是与古植物组合的性质有关。

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引用次数: 0

Successional stages of a Maastrichtian plesiosaur fall community from Antarctica 南极马斯特里赫特蛇颈龙坠落群落的演替阶段

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2025-12-23 DOI: 10.1016/j.cretres.2025.106306

Marianella Talevi , Soledad Brezina , Darío G. Lazo

Research on ecological successions in recent skeletal remains, such as those of whales, has revealed specific colonization patterns and four distinct succession phases. These succession patterns can also be inferred in the fossil record from evidence such as bioerosion traces, bone encrustation, and associated body fossils. The study of ecological successions in fossil bones of Mesozoic marine reptiles not only helps to understand the phases of degradation and entombing in the past but also contributes to our knowledge of the communities associated with these carcasses during that time. In this work, the presence of sclerobionts (represented by micro and macroborings) in bone remains of a plesiosaur from the upper Maastrichtian of Antarctica was identified and described, interpreting the phases of ecological succession in a high-latitude marine environment. Macroborings were assigned to Trypanites and Osedacoides. The microborings, similar to Wedl tunnels, were attributed to cyanobacteria and fungi, indicating that the bones were exposed for a long time. Furthermore, framboid pyrite in the bones shows anaerobic stages associated with bacterial activity. The four known stages of ecological succession were documented: the mobile scavenger stage, identified by bite marks; the opportunistic enrichment stage by Osedacoides; the sulfophilic stage, marked by modified vascular channels filled with pyrite; and the reef stage, by Trypanites traces, which indicate colonization by organisms before final burial. These findings enhance our understanding of the interactions between microorganisms and mineralization in ancient marine vertebrates, and aid in reconstructing paleocommunities associated with marine reptile falls, offering valuable insights into past ecosystem dynamics.

对最近骨骼遗骸（如鲸鱼骨骼）的生态演替研究揭示了特定的殖民模式和四个不同的演替阶段。这些演替模式也可以从化石记录的证据中推断出来，如生物侵蚀痕迹、骨痂和相关的身体化石。对中生代海洋爬行动物骨骼化石的生态演替研究不仅有助于了解过去海洋爬行动物的退化和埋藏阶段，而且有助于我们了解当时与这些尸体相关的群落。在这项工作中，在南极洲上马斯特里赫特的蛇颈龙骨骸中发现并描述了以微孔和大孔为代表的硬骨化石，解释了高纬度海洋环境中生态演替的阶段。大钻孔属于锥虫纲和锥虫纲。这些微钻孔与维德尔隧道相似，被认为是蓝藻和真菌造成的，这表明这些骨头暴露在地下很长时间。此外，骨骼中的树状黄铁矿显示与细菌活性相关的厌氧阶段。记录了四个已知的生态演替阶段：通过咬痕识别的移动食腐动物阶段；Osedacoides的机会富集阶段；亲硫期，以充满黄铁矿的修饰维管通道为标志；礁石阶段，通过锥虫的痕迹，表明生物在最终埋葬之前的殖民。这些发现增强了我们对古代海洋脊椎动物中微生物与矿化之间相互作用的理解，并有助于重建与海洋爬行动物瀑布相关的古群落，为过去的生态系统动态提供了有价值的见解。

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引用次数: 0

Isolated teeth of small theropods from the El Gallo Formation, Baja California, Mexico 墨西哥下加利福尼亚埃尔加洛组小型兽脚亚目恐龙的牙齿

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2025-12-12 DOI: 10.1016/j.cretres.2025.106292

Vanessa Alexandra García-Gil , Angélica Torices , Mirella López-Miguel , Marisol Montellano-Ballesteros

In this work, 47 isolated small theropod teeth from different microsites of “El Gallo” Formation, Baja California, Mexico are studied. Isolated theropod teeth constitute important evidence to analyse theropod diversity, since they are quite common in the fossil record. For their identification, we conducted morphological comparisons using multivariate and cladistic analyses comparing them with previously described small theropod teeth from Upper Cretaceous North America Formations. This dental material can be assigned mainly to two families: Dromaeosauridae, Troodontidae; and one subfamily: Saurornitholestinae. Also, some of the teeth were assigned to Richardoestesia and two specimens were indeterminate. Dromaeosaurids represent the most abundant group of theropods in “El Gallo” followed by the Richardoestesia dental Morphotype. This diversity pattern is similar to the one reported in the Aguja Formation of Texas for the same period of time. The use of multivariate statistical techniques and cladistic analyses allowed us to evaluate the similarity between specimens, however, taxonomical assignments are difficult due to the lack of knowledge of intraspecific morphological and/or ontogenetic variation that can lead to misinterpretations. Even so, the sample of 47 specimens yields valuable information that allows suggesting the presence of certain taxa and providing knowledge of the diversity of the continental Cretaceous fauna in Mexico.

在这项工作中，从墨西哥下加利福尼亚州“El Gallo”组的不同微遗址中分离了47个小兽脚亚目恐龙牙齿。孤立的兽脚亚目恐龙牙齿是分析兽脚亚目恐龙多样性的重要证据，因为它们在化石记录中相当普遍。为了鉴定它们，我们使用多元和分支分析进行了形态学比较，并将它们与先前描述的上白垩纪北美地层的小型兽脚亚目恐龙牙齿进行了比较。这种牙齿材料主要可分为两科：踏齿兽科，齿齿兽科；还有一个亚科：龙臀亚科。另外，一些牙齿被归为理查氏缺失，两个标本不确定。在El Gallo地区，Dromaeosaurids是数量最多的兽脚亚目类群，其次是Richardoestesia齿形。这种多样性模式与同一时期在德克萨斯州Aguja组中报道的相似。使用多元统计技术和分支分析使我们能够评估标本之间的相似性，然而，由于缺乏对种内形态和/或个体发生变异的了解，分类分配很困难，这可能导致误解。即便如此，47个标本的样本还是提供了有价值的信息，可以表明某些分类群的存在，并提供了墨西哥白垩纪大陆动物多样性的知识。

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引用次数: 0

The impact of transgression on the development model of lacustrine source rocks: Insights from the Upper Cretaceous Qingshankou Formation source rocks in the Songliao Basin 海侵对湖相烃源岩发育模式的影响——来自松辽盆地上白垩统青山口组烃源岩的启示

IF 1.7 3区地球科学 Q1 GEOLOGY

Cretaceous Research

Pub Date : 2025-12-11 DOI: 10.1016/j.cretres.2025.106302

Cheng Wu , Lin Chen , Zongsheng Lu , Jiaxin Yan , Kening Lu

The extensive deposition of black shales during the Cretaceous Period formed significant petroleum resources. Sea-level rise and tectonic activity often led to seawater incursions into terrestrial lacustrine basins, a process linked to the formation of high-quality hydrocarbon source rocks. However, the precise influence of these marine transgression events on source rock deposition remains poorly constrained. This study investigates the Qingshankou Formation in the Songliao Basin by integrating paleontological, inorganic, and organic geochemical data. Four discrete marine incursion events were identified, allowing for the reconstruction of paleoclimatic conditions, depositional environments, organic matter provenance, and primary productivity levels. Based on these results, three depositional models are proposed: ‘Burst’, ‘Destroy’, and ‘Slow’. The ‘Burst’ model enhances the formation of high-quality source rocks by increasing primary productivity via marine algae and nutrient influx, which fosters an anoxic environment favorable for organic matter preservation. In contrast, the ‘Destroy’ model inhibits source rock formation, as excessive terrestrial detrital input dilutes organic matter and disrupts anoxic preservation conditions. Finally, the ‘Slow’ model has an indirect influence and typically follows the ‘Destroy’ phase. During this subsequent stage, the lacustrine environment becomes relatively stable, inheriting the abundant nutrient load from preceding phase while developing the persistent anoxia through internal biogeochemical regulation within the lake system, which is required for effective organic matter preservation. Ultimately, the interplay between high productivity and favorable preservation conditions represents the key control on source rock formation in marine-influenced lacustrine systems.

白垩纪黑色页岩的广泛沉积形成了重要的石油资源。海平面上升和构造活动经常导致海水侵入陆相湖盆，这一过程与优质烃源岩的形成有关。然而，这些海侵事件对烃源岩沉积的确切影响尚不清楚。综合古生物学、无机地球化学和有机地球化学资料，对松辽盆地青山口组进行了研究。确定了四个离散的海侵事件，从而重建了古气候条件、沉积环境、有机质来源和初级生产力水平。在此基础上，提出了3种沉积模式：“Burst”、“Destroy”和“Slow”。“Burst”模式通过海洋藻类和营养物质流入提高初级生产力，促进了优质烃源岩的形成，从而形成有利于有机质保存的缺氧环境。相反，“破坏”模式抑制了烃源岩的形成，因为过量的陆地碎屑输入稀释了有机质，破坏了缺氧保存条件。最后，“缓慢”模式具有间接影响，通常在“破坏”阶段之后。在这一阶段，湖泊环境相对稳定，在继承前一阶段丰富的营养负荷的同时，通过湖泊系统内部的生物地球化学调节，形成持续的缺氧，这是有效保存有机质所必需的。最终，高生产力和有利保存条件的相互作用是海相湖相体系烃源岩形成的关键控制因素。

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引用次数: 0