Andrej Spiridonov
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andrejpaleo.bsky.social
Andrej Spiridonov
@andrejpaleo.bsky.social
4.4K followers 2.6K following 1K posts
Professor of paleontology and Earth systems at Vilnius University. My interests are: theoretical paleontology, evolution, geology, stratigraphy, philosophy of biology and geology, climate at scales great and small.
https://twitter.com/AndrejSpiridon4
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andrejpaleo.bsky.social
Thus wide-range variability gave us an idea on exploring the uncertainty in correlation using recurrence plots. It turns out, that even in the face of such unevenness of the record, the correlation of cores with widely different densities of occurrence was rather uniform.
5/5
Stratigraphical variation between correlation lines in cross-recurrence plots.
December 5, 2025 at 11:00 AM
andrejpaleo.bsky.social
The section yielded some very beautiful but extremely variable in their abundance conodonts. Power law behavior of conodont communities shown up as the dominance of extreme lacunas with baren samples (times of stress) intercalated with order of magnitude jumps in productivity!
4/5
Ludlow conodont elements from the Lapgiriai-1 section. Conodont stratigraphical series and their histograms in the Viduklė-61 and Lapgiriai-1 cores.
December 5, 2025 at 10:58 AM
andrejpaleo.bsky.social
Here we applied tools of the quantitative stratigraphy and dynamical systems: #recurrence_plots and the cross recurrence plots in revealing time correlation across different parts of the basin, according to the taxonomic compositions of conodont communities.
3/5
Autorecurrence and cross-recurrence plots with correlation lines between cores.
December 5, 2025 at 10:56 AM
andrejpaleo.bsky.social
Here, we tracked in detailed paleoenvironmental changes as reflected by the fabric of rocks reflected changes in the relative sea level which happened on the background of major biogeochemical perturbations and the extinction episode.
2/2
Carbonate facies of the Lapgiriai-1 core. Carbonate facies of the Lapgiriai-1 core.
December 5, 2025 at 10:54 AM
andrejpaleo.bsky.social
Glad to share our new article which is dedicated to the stratigraphy and paleoenvironments (facies)of the Ludfordian (late Silurian) in relation to the largest carbon isotopic excursion of the Phanerozoic — Lau Extinction Event
1/5
www.geology.cz/bulletin/ful...
🧪 #Geology #Macroecology #Paleobio
Stratigraphical Ludlow (late Silurian) section in the Lapgiriai-1 core.
December 5, 2025 at 10:49 AM
andrejpaleo.bsky.social
Long-range travels is an important factor in the geodispersal of vertebrates, modulating ever present force of the Geo-Red Queen, while merging individual geobiomes.
[For the further context you can read: www.nature.com/articles/s41... and doi.org/10.1017/pab.... ]
🧪 #EvoBio #Paleobio
Hierarchy of barriers impeding homogenization and the synchronization of biota
December 3, 2025 at 2:46 PM
andrejpaleo.bsky.social
Isn't that crazy -- there was a dog breed which was solely dedicated for powering wheels which turned meat on fire!?
Just how many kinds of such 'techno-animals' existed and went extinct? This is cultural and biological evolution all at once.
🧪 #EvoBio #Paleobio
Illustration of a dog turning wheel and meet on fire. Description of an extinct dog breed which was dedicated for turning wheels
December 3, 2025 at 2:40 PM
andrejpaleo.bsky.social
"Here we show substantial declines in the rates of collection of specimen data over recent decades, from analysis of over 150 million records from the Global Biodiversity Information Facility (GBIF) spanning more than two centuries"
www.nature.com/articles/s41...
🧪 #Macroecology #EvoBio #Paleobio
GBIF specimen records—number of specimens, unique species and spatial extent for Chordata, Arthropoda and Plantae (1950–2019).
November 25, 2025 at 11:04 PM
andrejpaleo.bsky.social
While discussing ideas on the evolution with @svalver.bsky.social and wandering around wonderful Barcelona, I'm learning some architectural paleontology. Giant (pea-sized) foraminifera — Nummulites and some sea urchin spines. Provenance probably local Eocene «piedra de Gerona», España.
🧪⚒️ #Geology
Nummulites Sea urchin spines in the Nummulites matrix Sea urchin spines in the Nummulites matrix
November 25, 2025 at 8:16 PM
andrejpaleo.bsky.social
At lunch with @svalver.bsky.social found this amazing anatomy of Gilt-head bream (Sparus aurata). The teeth of a durophagous predator of small shelly prey.
Globular teeth of Gilt-head bream (Sparus aurata).
November 25, 2025 at 8:16 AM
andrejpaleo.bsky.social
"72% of past continental areas across the Cenozoic lack accessible sedimentary rocks..remaining 28%..disproportionately derived from regions that experienced tropical, temperate, and arid climates..cold and polar climates are underrepresented."
doi.org/10.1016/j.pa...
🧪 ⚒️ #Geology #EvoBio #Paleobio
Extent of each main Koppen-Geiger climate zone (shown in gray) and corresponding lithological areas with fossilization potential per time interval (shown in the same colour previously assigned to each climate zone: tropical (red), arid (orange), temperate (pink), cold (light brown), and polar (light blue)).
November 21, 2025 at 2:13 PM
andrejpaleo.bsky.social
"The three great evolutionary faunas" of topic development in the "Systematic Biology" journal? 😃
Seems like decadal-scale topic displacement trends.
academic.oup.com/sysbio/advan...
🧪 #EvoBio #Paleobio #philsci
Numbers of research articles per topic published in Systematic Zoology and Systematic Biology during 1952 - 2025. Topic prediction divided articles into three main clusters, which then secondarily divided articles by inferred topic within each cluster (colors). Article counts were smoothed with a 5-year moving average to improve readability.
November 20, 2025 at 8:18 AM
andrejpaleo.bsky.social
Interesting meta-scientific take on the development of theories, as exemplified by the case of paleontology in the Modern Synthesis and the specific Late Turkana mollusk study of the punctuated equilibria.
link.springer.com/article/10.1...
🧪 ⚒️ #EvoBio #Paleobio #philsci
Summary of the interaction between the Modern Synthesis and paleontology
November 18, 2025 at 3:52 PM
andrejpaleo.bsky.social
Although, the author misrepresents our proposed Bretskyan hierarchy (BH) claiming that it lacks reticulate causation.
The BH is explicitly reticulate in diachronic view when different geobiomes can not only diverge but also merge together.
doi.org/10.1017/pab....
2/2
🧪 ⚒️ #EvoBio #Paleobio
Conceptual figure of spatiotemporal dynamics of large Bretskyan units (geobiomes) at two levels.
November 18, 2025 at 11:45 AM
andrejpaleo.bsky.social
Interesting article on the role of reticulation in evolution:
"...review tries to draw attention to evolutionary processes that lead to the origin and growth of diversity and complexity in biological systems by reticulations...‘Biology’s Second Law’"
www.mdpi.com/2079-7737/14...
🧪 #EvoBio
1/2
The architecture of a nested compositional hierarchy of biological entities and the potential outcomes of reticulation events among entities at a focal level.
November 18, 2025 at 11:40 AM
andrejpaleo.bsky.social
Eruption of the Hunga Tonga–Hunga Haʻapai in 2022 was a unique phreatic eruption even where we can learn many things on the effects of explosive eruptions on the Earth system.
Eruption was so large that in the atmosphere formed transient ice ring.
www.nature.com/articles/s43...
🧪 ⚒️ #Geology
Satellite-based estimation of the temporal evolution of temperature in the lower-middle stratosphere (LMS; 6–52 hPa; 21–35 km) within the ice-ring region Hunga Tonga–Hunga Haʻapai eruption and the ice ring
November 15, 2025 at 5:18 PM
andrejpaleo.bsky.social
Dogs and other domesticated animals present an unique set of natural-cultural supra-specific diversification under human sorting. Given analysis combined the data on dogs across range of times. Interestingly though, Holocene dogs were diverse!
www.science.org/doi/epdf/10....

🧪 ⚒️ #EvoBio #Paleobio
Geographic and temporal diversity, skull size, and shape variation of the canid specimens analyzed. Identification of specimens outside the diversity of the wolf.
November 14, 2025 at 8:18 PM
andrejpaleo.bsky.social
"we first show that rates of evolution estimated as a parameter in the unbiased random walk model lack a rate–time scaling when data has been generated using this model, even when time series are made incomplete and biased."
🧪 ⚒️ #EvoBio #Paleobio
academic.oup.com/evolut/advan...
Relationship between rate and time in simulated data.
November 13, 2025 at 2:19 PM
andrejpaleo.bsky.social
Biological accommodation of climatic variability is a first order factor enabling success of species. An excellent study of temperature niche breadth and geographical ranges of terrestrial plants.
doi.org/10.1073/pnas...
🧪 ⚒️ #EvoBio #Paleobio #Macroecology
Global map of species (A) geographic range size, and (B) niche breadth.
November 13, 2025 at 2:02 PM
andrejpaleo.bsky.social
Here are my 0.02 $
🧪 #EvoBio
Sydney Sweeney meme
November 12, 2025 at 7:35 AM
andrejpaleo.bsky.social
A big review of the evolution of bats:
www.annualreviews.org/content/jour...
🧪 ⚒️ #Paleobio #EvoBio
Adaptive landscape and the evolution of flight in mammals
November 9, 2025 at 9:56 PM
andrejpaleo.bsky.social
This illustration from a classic, reminds us, that we need all three approaches to the ancient worlds:
Palæontography - the description of past life forms
Palæobiology - purely biological theoretical outlook
Palæontology - a holistic study of the past, combining different fields.
🧪 ⚒️ #Paleobio
Slimonia acuminata from the: Woodward, H., 1878. A monograph of the British fossil Crustacea, belonging to the Order Merostomata. Monographs of the Palaeontographical Society, 32(145), pp.ii-263.
November 5, 2025 at 9:16 PM
andrejpaleo.bsky.social
If you need a professional terrestrial phototroph you need a symbiont of plant+fungi. Lichen (Spongiophyton sp) colonized the land already at least in the Early Devonian:
www.science.org/doi/10.1126/...
🧪 ⚒️ #Paleobio #EvoBio #Geology
Paleogeographical distribution of Spongiophyton by the Early Devonian Spongiophyton paleoart Internal cellular structures
November 3, 2025 at 3:03 PM
andrejpaleo.bsky.social
Eva sends best regards from her kindergarten!
Model of a pumpkin by Eva
October 31, 2025 at 1:24 PM
andrejpaleo.bsky.social
Historical reflection by a legendary biometrician, morphometrists, and statistician F. James Rohlf on the emergence of mathematization of the classification and systematics during his life time.
academic.oup.com/sysbio/advan...
🧪 ⚒️ #Paleobio #EvoBio
The title of the article: "Too many numbers?"
October 31, 2025 at 1:18 PM