Cretoperipatus
| Cretoperipatus Temporal range: Cenomanian
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Onychophora |
| Family: | Peripatidae |
| Genus: | †Cretoperipatus Engel & Grimaldi, 2002 |
| Species: | †C. burmiticus
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| Binomial name | |
| †Cretoperipatus burmiticus | |
Cretoperipatus burmiticus is an extinct species of velvet worm known from multiple specimens in Burmese amber. It lived in Myanmar's Kachin State during the Cenomanian age of the Late Cretaceous. One fossil was exceptionally preserved, allowing detailed analysis of its fine anatomy. Cretoperipatus had a pair of antennae, two simple eyes, clawed legs, and a pair of slime papillae, showing it was a crown-group onychophoran. Based on details of its anatomy, Cretoperipatus is placed in the family Peripatidae, likely grouping with basal Asian genera like Eoperipatus and Typhloperipatus.
Discovery and naming
[edit]Cretoperipatus was first described in 2002 paper by David A. Grimaldi, Michael S. Engel, and Paul C. Nascimbene.[1] The animal was then redescribed in 2016 by Ivo de Sena Oliveira, Ming Bai, Henry Jahn, Vladimir Gross, Christine Martin, Jörg U. Hammel, Weiwei Zhang, and Georg Mayer after acquiring more specimens.[2]
Both the holotype (AMNH Bu218) and various topotypes (BU-001467, BU-001468, ZZZ0066) were found in Burmese amber near Tanai Village in what is now Myanmar's Kachin State.[1][2] Additional undescribed specimens were found in the same location, showing this animal was fairly abundant.[3] All fossils have a maximum age of 98.79 ± 0.62 million years old, meaning the animal lived at the beginning of the Late Cretaceous during the Cenomanian Age.[3][4]: S1
The genus name is derived from the root "creto-", meaning Cretaceous, and "Peripatus", the type genus of the family Peripatidae. The species name "burmiticus" references the taxon being known from Burmese amber.[1]
Description
[edit]Due to being encased in amber, Cretoperipatus specimens preserve minute details that would otherwise disappear in the typical fossilization process. One specimen (BU-001468) is preserved in three dimensions, allowing researchers to create an intricate 3D render of its anatomy.[2]
Dermal Papillae
[edit]Cretoperipatus's body was covered in rings of bumps known as dermal papillae.[1][2] One of the most prominent types was primary papillae.[2] These have a bristle at their tip and would have given the animal a sense of touch.[5] In Cretoperipatus, the primary papillae are divisible into three parts: a larger part on the bottom known as a basal piece, a smaller part in the middle known as the apical piece, and a bristle on top used for sensing the environment. In Cretoperipatus, the basal piece is easily distinguishable from the apical piece and has five scale ranks. The apical piece is asymmetrically shaped because it has three scale ranks in the front and two in the back. In addition to primary papillae, Cretoperipatus possessed accessory papillae without a sensory bristle. These had a type 1 crater shape with an apical collar composed of 8 scales.[2]
Head
[edit]Cretoperipatus had a single pair of antennae with simple eyes called ocelli at their base. The top of the antenna possessed rings of specialized primary papillae known as type 1 sensilla.[2] These are distinguished from regular primary papillae by their prominent apical piece and the bristles having a textured base.[5] The undersides of the antennae possessed an array of spindle-shaped sensilla.[2] These papillae are similar to type 1 sensilla, but have a large, spindly-shaped basal piece.[5] In addition to papillae, the animal possessed a pair of frontal organs at the base of the antennae and beneath the eyes.[2]
Cretoperipatus had a ventral (bottom-facing) mouth with two internal jaws. In the original description, the animal's genital pad was mistaken for the mouth.[1][2] This was due to the holotype's poor preservation and the two structures looking similar. When looking at the structure of its internal jaws, these had a diastema and diastemal membrane. Cretoperipatus also possessed a pair of slime papillae. These were somewhat hard to distinguish, even when using x-ray microscopy.[2]
Trunk
[edit]Cretoperipatus had around twelve annuli (rings) of dermal papillae on each segment of its trunk.[1] The annuli were composed of both primary and accessory papillae and did not fuse laterally. Cretoperipatus had a visible dorsal midline running along the middle of its back. On its underside, the trunk preserved traces of the preventral and ventral organs. At the very end of this, Cretoperipatus had a genital pad between its penultimate (second to last) pair of legs.[2]
Lobopods
[edit]Cretoperipatus had a pair of legs known as lobopods on each segment of its trunk. Like in other velvet worms, the lobopods had a papillae-covered base, spinose pads or cushions, and a clawed foot.[1][2] The animal had no coxal organs on any legs and lacked crural papillae on the front-most pairs. However, all legs have a nephridial opening at their base.[1]
Cretoperipatus was originally interpreted as having only three spiny pads per lobopod,[1] yet better specimens show most of them have four.[2] The original describers probably mistook the holotype's back with its front, as this specimen was poorly preserved, and a velvet worm's endmost legs have fewer cushions. On a typical leg of Cretoperipatus, the distal (furthest away from the trunk) and proximal (closest to the trunk) cushions are thinner than the two in between. The third cushion (2nd closest to the body) was also split in two by a nephridial tubercle, an organ used to dispel waste.[2]
Cretoperipatus's foot had five basal papillae, with the bottom-most two being weakly developed.[1] At the end of the foot were two distal papillae. These were located on either side of a pair of claws. Many of these claws were detached and found floating in the amber matrix. This makes sense, as in modern velvet worms, the claws are connected by only a fragile membrane of tissue.[2]
Classification
[edit]| Proposed phylogenetic position.[2] |
Cretoperipatus burmiticus is one of the two fossils confidently assigned to Onychophora, the other being the Late Carboniferous Antennipatus.[3][6] As of now, Cretoperipatus is the only described Mesozoic onychophoran.[2] Unlike Antennipatus, Cretoperipatus is confidently assigned to the velvet worm crown group.[3]
When first described by Grimaldi et al., Cretoperipatus was assigned to the family Peripatidae.[1] This assignment was based on the following characteristics: Cretoperipatus had around 12 complete annuli on each segment of its trunk, the trunk annuli did not fuse laterally, its nephridial opening was at the base of the lobopods, it lacked crural papillae on the front-most legs, it lacked coxal organs,[1] its primary papillae were divisible into two parts (basal and apical), its genital pad was between the penultimate legs, it possessed spindle-shaped sensilla on its antennae, and it had a diastema on its jaw blade.[2]
The position of Cretoperipatus was further refined by Oliveira et al., who found it grouped with the basal, South Asian genera Eoperipatus and Typhloperipatus.[2] These were suspected to be sister taxa based on morphology, but finally confirmed using molecular analysis.[7] Like the genera above, Cretoperipatus had two distal papillae on its feet (other peripatids have three or more). It lacked the ventral fields of modified scales present in various Eoperipatus species. Unlike Eoperipatus but similar to Typhloperipatus, the foot's nephridial tubercle opening was on the third spinous pad rather than higher up. However, unlike Typhloperipatus, Cretoperipatus possessed eyes.[2] Based on these characters, Cretoperipatus is likely the closest relative of Typhloperipatus. However, this relationship has not been phylogenetically tested.[3]
Paleobiology and Paleoenvironment
[edit]Implications
[edit]Zoogeography
[edit]Early on, it was hypothesized that onychophorans arrived in Asia due to northwards drift of India, which at the time was an independent continent. This was known as the "Out of India" hypothesis and explained how velvet worms colonized South and Southeast Asia. Cretoperipatus refutes this, as it had clear affinities with Asian velvet worms and was present before the Asia-India collision during the Late Oligocene. Some time after this, peripatids began colonizing Northeast India, probably from Myanmar.[2] Combined with the presence of other Northern Hemisphere onychophorans (Antennipatus, Helenodora, and tentatively Succinipatopsis), velvet worms occurred in Laurasia (the precursor of North America and Eurasia) far longer than originally thought.[2][4]
References
[edit]- ^ a b c d e f g h i j k l m n Grimaldi, David A.; Engel, Michael S.; Nascimbene, Paul C. (March 2002). "Fossiliferous Cretaceous Amber from Myanmar (Burma): Its Rediscovery, Biotic Diversity, and Paleontological Significance". American Museum Novitates (3361): 1–71. doi:10.1206/0003-0082(2002)361<0001:FCAFMB>2.0.CO;2. hdl:2246/2914. S2CID 53645124.
- ^ a b c d e f g h i j k l m n o p q r s t u v w Oliveira, I. S.; Bai, M; Jahn, H; Gross, V; Martin, C; Hammel, J. U.; Zhang, W; Mayer, G (2016). "Earliest Onychophoran in Amber Reveals Gondwanan Migration Patterns". Current Biology. 26 (19): 2594–2601. Bibcode:2016CBio...26.2594O. doi:10.1016/j.cub.2016.07.023. PMID 27693140.
- ^ a b c d e Giribet, Gonzalo; Buckman-Young, Rebecca S.; Costa, Cristiano Sampaio; Baker, Caitlin M.; Benavides, Ligia R.; Branstetter, Michael G.; Daniels, Savel R.; Pinto-da-Rocha, Ricardo (2018). "The 'Peripatos' in Eurogondwana? – Lack of evidence that south-east Asian onychophorans walked through Europe". Invertebrate Systematics. 32 (4): 840–863. doi:10.1071/IS18007.
- ^ a b Murienne, Jerome; Daniels, Savel R.; Buckley, Thomas R.; Mayer, Georg; Giribet, Gonzalo (2014-01-22). "A living fossil tale of Pangaean biogeography". Proceedings of the Royal Society B: Biological Sciences. 281 (1775): 20132648. doi:10.1098/rspb.2013.2648. PMC 3866409. PMID 24285200.
- ^ a b c Oliveira, Ivo de Sena; Franke, Franziska Anni; Hering, Lars; Schaffer, Stefan; Rowell, David M.; Weck-Heimann, Andreas; Monge-Nájera, Julián; Morera-Brenes, Bernal; Mayer, Georg (2012-12-17). "Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species". PLOS ONE. 7 (12): e51220. Bibcode:2012PLoSO...751220O. doi:10.1371/journal.pone.0051220. ISSN 1932-6203. PMC 3524137. PMID 23284667.
- ^ Garwood, Russell J.; Edgecombe, Gregory D.; Charbonnier, Sylvain; Chabard, Dominique; Sotty, Daniel; Giribet, Gonzalo (2016). "Carboniferous Onychophora from Montceau-les-Mines, France, and onychophoran terrestrialization". Invertebrate Biology. 135 (3): 179–190. doi:10.1111/ivb.12130. ISSN 1077-8306. PMC 5042098. PMID 27708504.
- ^ Narayanan, Surya; Priyadarsanan, D.R.; Ranjith, A.P.; Sahanashree, R.; Neelavar Ananthram, Aravind (2025-05-04). "Rediscovery and phylogenetic position of a long-lost Typhloperipatus williamsoni Kemp, 1913 (Onychophora: Peripatidae) after 111 years from Arunachal Pradesh, India". Journal of Natural History. 59 (17–20): 1167–1180 [1168–1169, 1171–1176]. doi:10.1080/00222933.2025.2483434. ISSN 0022-2933.
External links
[edit]
Data related to Cretoperipatus at Wikispecies
