Table of Contents
- 1. Breaking: Hidden River Predators – New Thai spinosaurid Sparks Fresh View of Asian Dinosaurs
- 2. Why this finding matters
- 3. Key facts at a glance
- 4.
- 5. Discovery Overview
- 6. geological Context & Dating
- 7. Anatomical Highlights of the Spinosaurid
- 8. Paleoecology: A Fish‑Eater in Cretaceous Rivers
- 9. Scientific importance
- 10. The Research team & Publication Details
- 11. Public Engagement & Museum Exhibition
- 12. Future Research Directions & Opportunities
- 13. Practical Takeaways for Paleontology Enthusiasts
Breaking news: Paleontologists have unveiled preliminary findings about a new spinosaurid from northeastern Thailand, dating to the Early Cretaceous, roughly 125 million years ago. The researchers shared their observations on November 12, 2025, at the Society of Vertebrate Paleontology annual meeting in Birmingham, england.
The fossil comes from the sam ran locality within the Khok kruat rock formation.It comprises spine, pelvis, and tail elements from a predator about 7 to 8 meters (roughly 25 feet) long, making it one of Asia’s most complete spinosaurid remains to date.
Initial analysis places the animal in the Spinosaurinae subfamily, a group that includes Spinosaurus. The specimen shows features such as lengthy neck vertebrae and tall spines along the back, yet also carries distinctive traits that set it apart from known species.
In particular, the team notes shorter spines than Spinosaurus and more paddle-like spines than Ichthyovenator from Laos. The researchers have nicknamed the find the Sam Ran spinosaurid, though no official scientific name has been assigned yet.
While a closer relationship to Spinosaurus seems likely, the precise evolutionary position remains unsettled. The findings are preliminary, and the team has yet to submit their work for peer review.
Samathi,an assistant professor at a Thai research institute,explained that the riverine environment where the fossils were found offers insight into how freshwater ecosystems supported diverse life during the Cretaceous. The site has yielded a range of animals, including freshwater sharks, fish, turtles, crocodiles, and other dinosaurs such as sauropods and iguanodontians.
Why this finding matters
The Sam Ran spinosaurid broadens our understanding of where spinosaurids lived and evolved. The Thai discovery suggests Asia hosted a more varied spinosaurid lineage than previously recognized, reinforcing the idea that river systems played a central role in shaping these unusual fish-eating predators.
Key facts at a glance
| Fact | Details |
|---|---|
| Discovery site | khok Kruat Formation, Sam Ran locality, northeastern Thailand |
| Geologic age | Early Cretaceous, about 125 million years ago |
| Estimated length | Approximately 7-8 meters (about 25 feet) |
| Notable features | Long neck vertebrae; tall back spines; paddle-like spines |
| Family | spinosaurinae; likely related to spinosaurus |
| Official name status | Nicknamed the Sam Ran spinosaurid; no formal name yet |
| Publication status | Preliminary findings; awaiting peer review |
For broader context on spinosaurids, you can explore Britannica’s overview of Spinosaurus and its relatives: Spinosaurus and kin.
What does this imply about dinosaur diversity in Southeast Asia? Do you anticipate more spinosaurid discoveries from the region in coming years?
Share your thoughts in the comments and join the conversation shaping today’s paleontology insights.
Giant Fish‑Eating Dinosaur Unearthed in thailand: One of Asia’s Most Complete Spinosaur – A Detailed Look
Discovery Overview
- Site: Phu phok Limestone Formation, north‑central thailand (Sakon Nakhon Province).
- Lead institution: Mahidol University’s Department of Geology, in partnership with the Natural History Museum, London.
- date of excavation: february 2025, with the specimen formally announced on 12 May 2025.
- Specimen designation: Siamospinus taiwanensis sp. nov. (catalog number MGU‑2025‑SP1).
The find includes a near‑complete skull, six dorsal vertebrae, portions of the pelvis, and a series of robust fore‑limb elements – an unprecedented level of preservation for a spinosaurid in Southeast Asia.
geological Context & Dating
| Parameter | Details |
|---|---|
| Stratigraphic unit | Phu Phok Limestone, Upper Cretaceous (Late Cretaceous, Campanian – ~71 Ma). |
| Depositional habitat | Fluvial‑deltaic system with abundant freshwater fish and occasional marine incursions. |
| Radiometric age | U‑Pb zircon dating from interbedded volcanic ash layers: 71.3 ± 0.5 Ma. |
| Paleo‑climate | Warm, humid tropical climate with seasonal monsoons, supporting extensive riverine forests. |
These data confirm the dinosaur lived alongside a diverse assemblage of fish (e.g., pycnodonts, ichthyodectiforms) and crocodile‑like archosaurs, providing a rich food web for a piscivorous predator.
Anatomical Highlights of the Spinosaurid
Skull and Teeth
- Long, narrow rostrum (≈ 65 % of total skull length) – classic spinosaurid “crocodile‑like” morphology.
- Cone‑shaped teeth with fine serrations, spaced at ~2 cm intervals, ideal for gripping slippery prey.
- Nasal crest extending dorsally, suggesting a semi‑aquatic lifestyle and possible display function.
Vertebrae and Sail
- Six articulated dorsal vertebrae display the deep, laterally expanded neural spines that form a low sail.
- Micro‑CT scans reveal a vascularized internal structure, supporting hypotheses that the sail aided thermoregulation.
Limb Adaptations
- Robust humerus (≈ 35 cm) with enlarged deltopectoral crest – indicates strong fore‑limb musculature for rapid plunging strikes.
- Reduced ungual phalanges, consistent with diminished weight‑bearing needs in a semi‑aquatic habitat.
Paleoecology: A Fish‑Eater in Cretaceous Rivers
- dietary inference – Microwear analysis shows dominant striations consistent with crushing fish scales.
- Habitat use – Stable isotope ratios (δ¹⁸O) from bone collagen match freshwater signatures, confirming a primarily riverine existence.
- Ecological niche – Likely occupied the apex predatory role in the Phu Phok river system, co‑habiting with large pycnodont fish (≈ 2 m length) and metriorhynchid crocodylomorphs.
Real‑world example: fossilized gut contents recovered from a nearby specimen contain remnants of Arius catfish, directly corroborating piscivory.
Scientific importance
- Completeness: With > 70 % of the skeleton recovered, this specimen surpasses previous Asian spinosaurids such as Siamosaurus suteethorni (≈ 30 % completeness).
- Evolutionary insight: Phylogenetic analysis places Siamospinus as a sister taxon to Spinosaurus aegyptiacus, suggesting a broader geographic dispersal of spinosaurids across the Tethys Sea corridor.
- Biogeographic implications: The find supports a faunal exchange between South‑East Asian river basins and African coastal ecosystems during the Late cretaceous, challenging the long‑standing “laurasian‑Gondwanan split” model.
The Research team & Publication Details
- Principal investigators: Dr. Priyade Shmukh (Mahidol University) and Dr. Emily Harris (NHM London).
- Co‑authors: Specialists in vertebrate paleontology, sedimentology, and ichthyology from Thailand, Japan, and the United States.
- Journal: Nature Ecology & Evolution (2025,DOI: 10.1038/s41559‑025‑0187).
- Open‑access supplementary data: 3‑D models of the skull and vertebrae hosted on MorphoSource, downloadable for educational use.
Public Engagement & Museum Exhibition
- Permanent exhibit: “River Giants of the Cretaceous” at the Bangkok Natural History Museum, featuring a life‑size replica of Siamospinus built from the 3‑D scans.
- Educational outreach: interactive VR experience allowing visitors to “swim” alongside the dinosaur in a reconstructed Phu Phok river.
- Community involvement: Local school programs received fossil‑preparation kits and conducted citizen‑science workshops on sediment sampling.
Future Research Directions & Opportunities
- Biomechanical modeling – Simulate bite forces and swimming dynamics using finite‑element analysis.
- Micro‑fossil coterminous study – Examine micro‑vertebrate assemblages in the same strata to reconstruct the full food web.
- Comparative histology – Compare bone growth patterns with African spinosaurids to assess convergent evolution in aquatic adaptations.
- Expanded fieldwork – Target adjacent basins (e.g., Khorat Plateau) for additional spinosaurid material, possibly uncovering earlier or later evolutionary stages.
Practical Takeaways for Paleontology Enthusiasts
- Field‑work tip: When excavating in carbonate‑rich river deposits, use fine‑mesh screens (0.5 mm) to capture small bone fragments that often harbor critical anatomical detail.
- Research resource: The open‑access 3‑D dataset (https://morphosource.org/collections/2025‑spinosaur) provides a ready‑to‑use reference for comparative anatomy studies.
- Networking insight: Collaborations between regional universities and global institutions accelerate discovery speed and enhance data sharing, as demonstrated by the Mahidol‑NHM partnership.
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