DinoDex
Long-snouted spinosaurid with a low back ridge walking in side view beside a human silhouette
Life restoration of the Brazilian spinosaurid Irritator challengeri, with a human for scale.画像クレジット：Sauroarchive, CC BY 4.0, via Wikimedia CommonsCC BY 4.0出典（新しいタブで開きます）

Irritator challengeri

発音： IR-ih-tay-tor chal-en-JER-eye

Tetanurae · Spinosauridae

A spinosaurid from the Early Cretaceous of north-east Brazil, known from the most complete spinosaurid skull ever found. Its long, narrow snout and conical teeth suited catching fish and other small prey on a tropical coastal lagoon.

  • Bipedal
  • Crested
  • Possibly semiaquatic
比較
時代
白亜紀· アプチアン期
食性
魚食
全長
6–8 m
体重
1,000 kg
産地
Ceará, Brazil, South America

クイックアンサー

Irritator challengeriの大きさは？
Irritator challengeriの全長は約6–8 mでした。腰の高さは約1.8–2.4 mでした。体重は約1 tでした。 (Wikipedia: Irritator 2026; Paul 2016)
Irritator challengeriはいつ生きていた？
Irritator challengeriは白亜紀前期、約1.196億〜1.132億年前に生きていました。 (Paleobiology Database: Irritator challengeri … 2026; Schade et al. 2023)
Irritator challengeriの化石はどこで見つかった？
Irritator challengeriの化石はRomualdo Formation (Ceará)、Brazilで見つかっています。 (Martill et al. 1996; Sues et al. 2002)
Irritator challengeriは何を食べていた？
Irritator challengeriは魚食または肉食でした。 (Martill et al. 1996; Sues et al. 2002)
Irritator challengeriは誰がいつ命名した？
Irritator challengeriは1996年にDavid M. Martill et al.によって記載されました。 (Martill et al. 1996; Schade et al. 2023)

このページの内容

IR-ih-tay-tor chal-en-JER-eye

時代
白亜紀119.6–113.2 Ma
食性
魚食
全長
6–8 m
体重
1 t
産地
Brazil, South America
分類
Tetanurae · Spinosauridae
記載
1996, David M. Martill et al.

概要

このコンテンツは英語でご覧いただけます。

Irritator challengeri lived in the Araripe Basin of north-east Brazil in the late Aptian, a little over 113 million years ago. Its skull came out of a limestone concretion near Santana do Cariri, Ceará, and was sold by fossil dealers to the State Museum of Natural History in Stuttgart, Germany.

Dealers had built up the snout with plaster to make it look longer, which "irritated" the researchers who had to remove it; the species name honours Professor Challenger of Arthur Conan Doyle's "The Lost World". Martill and colleagues (1996) first thought it was a maniraptoran, and Sues and colleagues (2002) showed it was a spinosaurid.

CT scans by Schade and colleagues (2023) revealed almost the whole palate and braincase. The skull had binocular vision in front of the snout and a relatively weak but fast bite, and the lower jaws spread sideways when opening, like those of pelicans. It probably snapped up fish and small vertebrates, and a spinosaurid tooth has even been found in a pterosaur neck bone from the same rocks.

名前の意味

From "irritation", for the frustration caused by the dealers' alterations to the skull; challengeri after Professor Challenger in Conan Doyle's "The Lost World" (Martill et al. 1996).

生態と証拠

この動物がどのように暮らしていたかについての科学者の考えと、それぞれの説を支える証拠の強さです。

摂食

  • Irritator ate pterosaurs as well as fish.

    証拠レベル：仮説

    A spinosaurid tooth stuck in a pterosaur bone shows that some spinosaurid of the formation fed on one, by hunting or scavenging; it is not certain the tooth belonged to Irritator.

    賛成・反対の証拠 · 1
    支持する証拠

    • 生痕化石 · Spinosaurid tooth in a pterosaur vertebra (Romualdo Formation)

      A spinosaurid tooth embedded in a pterosaur neck vertebra from the same formation.

  • Irritator had a relatively weak but fast bite suited to snapping small prey.

    証拠レベル：中程度の証拠

    Jaw mechanics and the inner ear suggest quick snaps at fish and small vertebrates rather than a crushing bite.

    賛成・反対の証拠 · 2
    支持する証拠

    • 標本 · CT reconstruction of the Irritator skull

      Medical and micro-CT reconstructions of SMNS 58022 reveal the palate and braincase, binocular vision in front of the snout, a weak but fast bite and lower jaws that spread sideways when opening.

      標本： SMNS 58022

    • 比較解剖学 · Irritator braincase endocast

      A digital endocast and inner ear indicating fast, well-controlled downward head movements and a snout held angled about 45 degrees down.

      標本： SMNS 58022

その他

  • The Irritator holotype is the most complete spinosaurid skull known.

    証拠レベル：直接証拠

    Only the tip of the snout and the front of the lower jaws are missing, while other spinosaurids are known mostly from snouts and isolated bones.

    賛成・反対の証拠 · 1
    支持する証拠

    • 標本 · CT reconstruction of the Irritator skull

      Medical and micro-CT reconstructions of SMNS 58022 reveal the palate and braincase, binocular vision in front of the snout, a weak but fast bite and lower jaws that spread sideways when opening.

      標本： SMNS 58022

サイズ

全長
6–8 m

（26.2 フィート）

SMNS 58022 に基づく

体高
2 m文献上の範囲 1.8–2.4 m

（6.6 フィート）

体重
1,000 kg
Irritator challengeri の全長は約 8 m（26.2 ft）で、身長 1.8 m の成人のおよそ 4.4 倍です。

タイムライン

約 119.6〜113.2 百万年前（Ma）、中生代（252–66 Ma）に生息していました。

時代： アプチアン期 (121.4–113 Ma), 白亜紀前期 (145–100.5 Ma)

Late Aptian (Schade et al. 2023, after Arai & Assine 2020); PBDB gives the same bin, 119.57-113.2 Ma. Older works, and Wikipedia, date the Romualdo Formation to the Albian.

産地

累層

地図データ：Natural Earth（パブリックドメイン）。現在の位置で、当時の大陸の位置ではありません。

これは化石が見つかった場所で、この動物が暮らしていた範囲全体ではありません。

生態系

Restoration of the Romualdo Formation environment with Irritator challengeri in the foreground, Mirischia and Thalassodromeus in the background and pterosaurs overhead.画像クレジット：Composition and effects by PaleoGeekSquared Background by ItaiguaraLima Irritator and flying pterosaurs by Андрей Белов Thalassodromeus by PWNZ3R Dragon Mirischia by Ademar Pereira do Nascimento, CC BY 3.0, via Wikimedia CommonsCC BY 3.0出典（新しいタブで開きます）

生息環境： Romualdo (Araripe Basin)

119.57–113.2 百万年前 · 海岸縁, 湖

A tropical coastal lagoon with irregular freshwater influence and marine incursions, surrounded by arid to semi-arid land; famous for fish, pterosaurs and soft tissues preserved in limestone concretions.

分類

  1. クレードDinosauria
  2. クレードSaurischia
  3. クレードTheropoda
  4. クレードTetanurae
  5. 上科Megalosauroidea
  6. 科Spinosauridae
  7. 亜科Spinosaurinae
  8. 属Irritator
  9. 種Irritator challengeri

分類上の地位： 有効

化石記録

Holotype skull of Irritator challengeri, SMNS 58022, in left and right lateral view (Sales & Schultz 2017).画像クレジット：Marcos A. F. Sales, Cesar L. Schultz, CC BY 2.5, via Wikimedia Commons, Staatliches Museum für Naturkunde StuttgartCC BY 2.5出典（新しいタブで開きます）
標本
標本番号種別所蔵機関発見
SMNS 58022ホロタイプStaatliches Museum für Naturkunde Stuttgart (SMNS)—

見つかった部位

ホロタイプ: SMNS 58022

  • 保存
  • 部分的
  • 復元
  • 不明・未記録
部位ごと（表）
ホロタイプ: SMNS 58022 の骨格部位
部位状態
Skull部分的 · Missing most of the premaxillae and the front of the maxillae.
Mandible部分的 · Missing the front ends.
Teeth部分的
Cervical vertebrae不明・未記録
Dorsal vertebrae不明・未記録
Sacrum不明・未記録
Caudal vertebrae不明・未記録
Ribs不明・未記録
Gastralia不明・未記録
Scapula / shoulder girdle不明・未記録
Humerus不明・未記録
Forearm (radius / ulna)不明・未記録
Hand (manus)不明・未記録
Pelvis不明・未記録
Femur不明・未記録
Tibia / fibula不明・未記録
Foot (pes)不明・未記録
Skull reconstructions of Irritator challengeri (SMNS 58022) and Angaturama limai (USP GP/2T-5).画像クレジット：Marcos A. F. Sales, Cesar L. Schultz, CC BY 4.0, via Wikimedia CommonsCC BY 4.0出典（新しいタブで開きます）

ギャラリー

Historical reconstruction: the Irritator head as originally interpreted by Martill et al. (1996), with a head crest now known to be based on a misidentified bone fragment.画像クレジット：PaleoGeekSquared, CC BY-SA 4.0, via Wikimedia Commons (unmodified except resizing)CC BY-SA 4.0

すべての標本

発見

記載年
1996
記載者
David M. Martill et al.
タイプ標本
SMNS 58022

発見の年表

  1. 1996 · 正式に記載

    Martill and colleagues name Irritator

    Named as a crested maniraptoran, the first dinosaur named from the formation.

    人物：David M. Martill

  2. 2002 · 再検討

    Irritator redescribed as a spinosaurid

    After further preparation, Sues and colleagues confirm it is a spinosaurid.

    人物：Hans-Dieter Sues, David M. Martill

  3. 2023 · 主要な研究

    CT reappraisal of the Irritator skull

    Schade and colleagues reconstruct the whole skull digitally.

    人物：Marco Schade

出典

  1. (2026). Paleobiology Database: Irritator challengeri occurrence and type collection 28052. The Paleobiology Database (paleobiodb.org), data service 1.2, accessed 2026-09-23. https://paleobiodb.org/data1.2/colls/list.json?coll_id=28052&show=paleoloc,strat,loc,ref,geo&pgm=gplates&vocab=pbdb（新しいタブで開きます）
  2. (2026). Wikipedia: Irritator. Wikipedia (English), accessed 2026-09-24. https://en.wikipedia.org/wiki/Irritator（新しいタブで開きます）
  3. Martill, D. M., Cruickshank, A. R. I., Frey, E., Small, P. G. & Clarke, M. (1996). A new crested maniraptoran dinosaur from the Santana Formation (Lower Cretaceous) of Brazil. Journal of the Geological Society 153: 5-8. doi:10.1144/gsjgs.153.1.0005（新しいタブで開きます）
  4. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
  5. Schade, M., Rauhut, O. W. M. & Evers, S. W. (2020). Neuroanatomy of the spinosaurid Irritator challengeri (Dinosauria: Theropoda) indicates potential adaptations for piscivory. Scientific Reports 10: 9259. doi:10.1038/s41598-020-66261-w（新しいタブで開きます）
  6. Schade, M., Rauhut, O. W. M., Foth, C., Moleman, O. & Evers, S. W. (2023). A reappraisal of the cranial and mandibular osteology of the spinosaurid Irritator challengeri (Dinosauria: Theropoda). Palaeontologia Electronica 26(2): a17. doi:10.26879/1242（新しいタブで開きます）
  7. Sues, H.-D., Frey, E., Martill, D. M. & Scott, D. M. (2002). Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil. Journal of Vertebrate Paleontology 22: 535-547. doi:10.1671/0272-4634(2002)022[0535:ICASDT]2.0.CO;2（新しいタブで開きます）