| Caeruleum miraculum Temporal range: Early Cretaceous, | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Infraphylum: | Agnatha |
| Class: | Hyperoartia |
| Order: | Petromyzontiformes |
| Genus: | †Caeruleum Huang, 2023 |
| Species: | †C. miraculum |
| Binomial name | |
| †Caeruleum miraculum Huang, 2023 | |
Caeruleum is an extinct genus of lamprey from the Lower Cretaceous Jiufotang Formation of China. The genus contains a single species, C. miraculum, known from various specimens including complete and partial bodies. After Mesomyzon, Caeruleum is the second Cretaceous fossil lamprey named from China.[1]
Discovery and naming
The Caeruleum fossil material was discovered in sediments of the Jiufotang Formation near Naizi Mountain in Weichang County of Chengde City, Hebei Province, China. The holotype specimen, BMM 3770, consists of a complete animal preserved on a slab and counterslab. Several additional specimens of various levels of completion were also assigned to Caeruleum as paratypes. These include BMM 3771 (an incomplete specimen with a complete tail), BMM 3772 (the posterior end of an animal with a mutilated tail), BMM 3776 (the anterior end with a complete head), and BMM 3775, 3777, and 778 (nearly complete specimens missing the posterior ends).[1]
In 2023, Weijia Huang described Caeruleum miraculum as a new genus and species of lamprey based on these fossil remains. The generic name, "Caeruleum", implements the blue color caeruleum. The specific name, "miraculum", is derived from the Latin "mirabilis", meaning "wonderful", in reference to the nature of the fossil specimens. The full binomial name references the Blue Miracle Museum Science Research Studio in Guangzhou (Guangdong Province), China, where the specimens are housed.[1]
Caeruleum is the sixth named genus of fossil lamprey, after Mayomyzon, Pipiscius, Hardistiella, Mesomyzon, and Priscomyzon.[1]
Description
The Caeruleum specimens exhibit significant variation in size, ranging from 24–46.2 centimetres (9.4–18.2 in) in length. This is significantly larger than most other fossil lampreys and is comparable to some extant species. Like modern lampreys, Caeruleum had seven gill pouches, with the anterior dorsal fin originating after the last gill pouch. In comparison, the Cretaceous Mesomyzon from the Yixian Formation ranged from 15–21.7 centimetres (5.9–8.5 in) long, with the dorsal fin beginning after the fourth gill pouch.[1][2]
Paleoenvironment
The Caeruleum fossil material was discovered in layers of the Jiufotang Formation, which dates to the Aptian age of the Early Cretaceous period. Well-preserved fossils of many other animals, including non-avian dinosaurs, early birds, pterosaurs, mammals, turtles, lizards, and fish, have also been found here.[1][3]
References
- 1 2 3 4 5 6 Huang, Weijia (2023-09-01). "A new species of fossil lamprey (Petromyzontida: Petromyzontiformes) from Hebei, China". Historical Biology: 1–13. doi:10.1080/08912963.2023.2252443. ISSN 0891-2963.
- ↑ Wu, Feixiang; Chang, Mee-Mann; Janvier, Philippe (2021-11-25). "A new look at the Cretaceous Lamprey Mesomyzon Chang, Zhang & Miao, 2006 from the Jehol Biota". Geodiversitas. 43 (23): 1293–1307. doi:10.5252/geodiversitas2021v43a23. ISSN 1280-9659.
- ↑ Yu, Zhiqiang; Wang, Min; Li, Youjuan; Deng, Chenglong; He, Huaiyu (2021-12-01). "New geochronological constraints for the Lower Cretaceous Jiufotang Formation in Jianchang Basin, NE China, and their implications for the late Jehol Biota". Palaeogeography, Palaeoclimatology, Palaeoecology. 583: 110657. doi:10.1016/j.palaeo.2021.110657.