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Mecistocephalus spissus

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Mecistocephalus spissus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Chilopoda
Order: Geophilomorpha
Family: Mecistocephalidae
Genus: Mecistocephalus
Species:
M. spissus
Binomial name
Mecistocephalus spissus
Wood, 1862[1]

Mecistocephalus spissus is a species of soil centipede in the Mecistocephalidae family.[2] The American biologist Horatio Curtis Wood first described this species in 1862 based on type material found in Kauai or Oahu in Hawaii.[1][2] This centipede has only 45 pairs of legs,[3] the minimum number recorded in the genus Mecistocephalus.[4] This species was the first in this genus to be discovered with such a modest number of legs.[5]

Distribution

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The species is endemic to the Hawaiian Islands. This centipede is found on most of the major islands, mainly in mountainous areas. Published records report finds on Hawaii, Kauai, Maui, Molokai, Necker, and Oahu.[3]

Phylogeny

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A phylogenetic analysis of the family Mecistocephalidae based on morphology places this species in a clade with M. nannocornis,[6] which was the second species in the genus Mecistocephalus to be discovered with only 45 leg pairs.[5] This analysis also places this clade on the most basal branch of a phylogenetic tree of this genus, with a sister group formed by all the other species in this genus together in a separate clade. This analysis suggests that the common ancestor of the centipedes in this genus had 45 leg pairs and that the species in this sister group evolved through a process that added segments and increased the number of legs.[6]

Description

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This species is dark yellow-brown with no dark patches, has 45 leg pairs, and can reach 70 mm in length. The head has a trapezoidal shape, and both the head and body taper toward the posterior end.[3] The forcipules are stout,[7] and when closed, extend beyond the anterior margin of the head.[3] The sternum of the ultimate leg-bearing segment has the shape of a shield, and the ultimate legs are slender with scattered setae and no sexual dimorphism.[3]

Although both this species and its close relative M. nannocornis have only 45 leg pairs, there are also clear differences.[5] For example, M. spissus features a greater number of teeth on the four articles of the forcipules, with two on the first article, one on the second, one on the third, and two (one ventral and one dorsal) on the fourth.[3][8] The species M. nannocornis has only one distal tooth on the first article, a tubercle on the second, one tooth on the third, and no distinct tooth on the fourth.[5] Furthermore, M. spissus has a head with a length/width ratio of 1.7 to 1.8,[3] whereas M. nannocornis has a head that is unusually short,[9] with a length/width ratio of only 1.5.[5]

References

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  1. ^ a b Wood, H.C. (1862). "On the Chilopoda of North America with a catalogue of all the specimens in the collection of the Smithsonian Institution". Journal of the Academy of Natural Sciences of Philadelphia. 2. 5 (1): 5–52 [43].
  2. ^ a b Bonato, L.; Chagas Junior, A.; Edgecombe, G.D.; Lewis, J.G.E.; Minelli, A.; Pereira, L.A.; Shelley, R.M.; Stoev, P.; Zapparoli, M. (2016). "Mecistocephalus spissus Wood, 1862". ChiloBase 2.0 - A World Catalogue of Centipedes (Chilopoda). Retrieved 2024-06-08.
  3. ^ a b c d e f g Bonato, Lucio; Foddai, Donatella; Minelli, Alessandro (2004). "The Centipede Order Geophilomorpha in the Hawaiian Islands (Chilopoda)" (PDF). Bishop Museum Occasional Papers. 78: 13–32 [15].
  4. ^ Bonato, Lucio; DáNyi, LáSzló; Minelli, Alessandro (2010). "Morphology and phylogeny of Dicellophilus, a centipede genus with a highly disjunct distribution (Chilopoda: Mecistocephalidae)". Zoological Journal of the Linnean Society. 158 (3): 501–532 [515]. doi:10.1111/j.1096-3642.2009.00557.x.
  5. ^ a b c d e Uliana, Marco; Bonato, Lucio; Minelli, Alessandro (2007-01-22). "The Mecistocephalidae of the Japanese and Taiwanese islands (Chilopoda: Geophilomorpha)". Zootaxa. 1396 (1): 1–84 [30-32]. doi:10.11646/zootaxa.1396.1.1. ISSN 1175-5334.
  6. ^ a b Bonato, Lucio; Foddai, Donatella; Minelli, Alessandro (2003). "Evolutionary trends and patterns in centipede segment number based on a cladistic analysis of Mecistocephalidae (Chilopoda: Geophilomorpha)". Systematic Entomology. 28 (4): 539–579. doi:10.1046/j.1365-3113.2003.00217.x. ISSN 0307-6970.
  7. ^ Bonato, Lucio; Edgecombe, Gregory D.; Zapparoli, Marzio (2011). "Chilopoda – Taxonomic overview". In Minelli, Alessandro (ed.). The Myriapoda. Volume 1. Leiden: Brill. pp. 363–443. ISBN 978-90-04-18826-6. OCLC 812207443.
  8. ^ Bonato, Lucio; Edgecombe, Gregory; Lewis, John; Minelli, Alessandro; Pereira, Luis; Shelley, Rowland; Zapparoli, Marzio (2010-11-18). "A common terminology for the external anatomy of centipedes (Chilopoda)". ZooKeys (69): 17–51. Bibcode:2010ZooK...69...17B. doi:10.3897/zookeys.69.737. ISSN 1313-2970. PMC 3088443. PMID 21594038.
  9. ^ Chamberlin, Ralph V. (1920). "On chilopods of the family Mecistocephalidae". The Canadian Entomologist. 52 (8): 184–189 [187]. doi:10.4039/Ent52184-8. ISSN 1918-3240.