Open Paleo

Scipionyx

Dal Sasso & Signore, 1998 SHIH-pee-oh-nicks /ˈʃɪˌpiːoʊnɪks, ˌʃɪpiːˈoʊ-/

From the Roman name Scipio (after the Roman general Scipio Africanus, as the fossil was found in Italy) + Greek 'onyx' (claw), meaning 'Scipio's claw'.

113.2–100.5 million years ago Albian, Early Cretaceous
Early Cretaceous stages

Scipionyx was a genus of theropod dinosaur from the Early Cretaceous Pietraroja Formation of Italy, around 113 million years ago.

Under dispute

Scipionyx is known only from a hatchling, complicating its classification. Dal Sasso and Maganuco (2011) recovered it as a basal compsognathid, and Jones (2026) follows this. Cau (2024), however, recovered it as an immature spinosaurid within Megalosauroidea, arguing its compsognathid-grade appearance reflects juvenile morphology rather than affinity. It is retained in Compsognathidae pending study of adult material.

Diagnosis

  1. Five premaxillary teeth
  2. Sinusoidal ridge of the supratemporal fossa at the frontoparietal contact
  3. Descending process of the squamosal distally squared
  4. Carpus of only two stacked, well-ossified bones (radiale and distal carpal 1+2), the distal carpal lenticular, proximodistally compressed, non-semilunate, and fused without trace of a suture
  5. Manual digit III markedly longer (123%) than digit I
  6. Preacetabular blade of the ilium with its cranial concavity facing cranially and only slightly developed
  7. Prominent ischial obturator process squared distally

Species

Scipionyx samniticus Dal Sasso & Signore, 1998

Type species

From Latin 'samniticus' meaning 'of the Samnites' or 'Samnian', referring to Samnium, the ancient region of south-central Italy where the holotype was found.

Holotype
SBA-SA 163760 , Soprintendenza per i Beni Archeologici di Salerno, Avellino, Benevento e Caserta
Material
Nearly complete, articulated skeleton with exceptional soft-tissue preservation, including the intestine, muscle fibers, trachea, liver remains, and mesenteric blood vessels.
Notes
The only known specimen (nicknamed "Ciro"); dal Sasso and Maganuco (2011) assessed it as a neonate, probably less than three weeks old at death, from its open frontoparietal fontanelle and neurocentral sutures unclosed throughout the vertebral column.
Horizon
Albian, Early Cretaceous , 113.2–100.5 million years ago
Locality
Le Cavere quarry, Pietraroja, Benevento, Italy

References

  1. Dal Sasso, C.; Signore, M. (1998). Exceptional soft-tissue preservation in a theropod dinosaur from Italy. Nature 392: 383-387. dalsasso1998a
  2. Dal Sasso, C.; Maganuco, S. (2011). Scipionyx samniticus (Theropoda: Compsognathidae) from the Lower Cretaceous of Italy — osteology, ontogenetic assessment, phylogeny, soft tissue anatomy, taphonomy and palaeobiology. Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano 37(1): 1-281.

    Comprehensive 281-page monograph on the only known specimen; provides the emended diagnosis, full osteology, a neonate ontogenetic assessment, phylogeny, and soft-tissue anatomy.

    dalsasso2011a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the body length, mass, and hip height estimates.

    jones2026c
  4. Cau, A. (2024). A Unified Framework for Predatory Dinosaur Macroevolution. Bollettino della Società Paleontologica Italiana 63(1): 1-19. doi:10.4435/BSPI.2024.08

    Recovered Scipionyx as an immature spinosaurid within Megalosauroidea.

    cau2024a