Mecistocephalus

Last updated

Mecistocephalus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Chilopoda
Order: Geophilomorpha
Family: Mecistocephalidae
Genus: Mecistocephalus
Newport, 1843 [1]
Type species
Mecistocephalus punctifrons
Newport, 1843

Mecistocephalus is the largest genus of centipedes in the family Mecistocephalidae, with about 140 species. [2] This genus is among the most diverse and widespread of all the genera in the order Geophilomorpha. [3] The British entomologist George Newport first proposed this genus in 1843 to contain a group of centipedes marked by an unusual elongation of the head. [4] [5]

Contents

Description

Centipedes in this genus range from 2 cm to 10 cm in length. [2] The head, forcipular segment, and their appendages are often elongated, [2] with a head that is obviously longer than wide. [3] A pair of sclerotized teeth (spicula) project from the pleurites on the sides of the head. [2] [3]

The coxosternum of the first maxillae is divided down the middle by a longitudinal suture, but the coxosternum of the second maxillae is undivided. The second maxillae reach beyond the first maxillae and are well developed with a simple claw. The forcipular tergum is slightly wider than long and divided down the middle by a longitudinal furrow. [3] Each of the first articles of the forcipules often features a pair of denticles, one distal and the other near the middle of the article. [2] [6] [7] The body tapers distinctly toward the posterior. The first pair of legs are markedly reduced in size. The ultimate legs are slender and do not exhibit sexual dimorphism. [3]

Centipedes in the genus Mecistocephalus usually have 45 to 51 pairs of legs, but some have more, up to as many as 101 leg pairs. [2] Most species in this genus have 49 pairs of legs (e.g., M. punctifrons and M. pallidus ), [3] but other species have 51 pairs (e.g., M. evansi and M. lifuensis ), 47 pairs (e.g., M. angusticeps and M. tahitiensis ), or 45 pairs (e.g., M. nannocornis and M. spissus ). [8] [9] Intraspecific variation in the number of leg-bearing segments within each sex has been recorded among the species with the greatest number of legs in this genus: M. diversisternus , which has 57 or 59 leg pairs, M. japonicus , which has 63 or 65 leg pairs, and M. microporus , which has odd numbers of leg pairs ranging from 93 to 101, the maximum number recorded in the family Mecistocephalidae. [10] [2]

Phylogeny

A phylogenetic analysis of the family Mecistocephalidae using morphological features places the genus Mecistocephalus in the subfamily Mecistocephalinae along with the genera Tygarrup , Krateraspis , and Takashimaia. The genera in this subfamily share a set of distinctive traits, including setae on the clypeus that are limited to a short transverse band. Diagnostic features also include a body that tapers toward the posterior end, a cephalic plate that is evidently longer than wide, a divided coxosternum of the first maxillae, an undivided coxosternum of the second maxillae, well developed second maxillae that each feature a reduced claw, and a forcipular tergum that is slightly wider than long and divided by a mid-longitudinal groove. [8]

Phylogenetic analysis based on morphology also places the genus Tygarrup on the most basal branch of a phylogenetic tree in the subfamily Mecistocephalinae, with the genus Krateraspis on the second most basal branch and the genus Takashimaia on the third most basal branch. This analysis leaves the species of Mecistocephalus in a clade forming a sister group for Takashimaia, which emerges as the genus most closely related to Mecistocephalus. [8] These two genera share an especially extensive set of traits: For example, unlike the other genera in the same subfamily, both Mecistocephalus and Takashimaia feature a spiculum on each side of the head. These two genera can be distinguished, however, based on other traits. For example, the second maxillae extend beyond the first maxillae in the genus Mecistocephalus but not in the genus Takashimaia. [11]

Phylogenetic analysis based on morphology also indicates that the common ancestor of the subfamily Mecistocephalinae had 45 leg pairs, with species featuring more leg pairs evolving through a process that added leg pairs incrementally. For example, this analysis indicates that the common ancestor of the genus Mecistocephalus also had 45 leg pairs and places extant species with 45 leg pairs in a clade on the most basal branch of a phylogenetic tree in this genus. These species form a sister group for a clade containing all other Mecistocephalus species, which share a common ancestor with 47 leg pairs. The second most basal branch in this genus contains a clade with 47 leg pairs, which forms a sister group for a clade containing the remaining Mecistocephalus species, which share a common ancestor with 49 leg pairs. Thus, Mecistocephalus species with more than 49 leg pairs evolved from a common ancestor with 49 leg pairs, which in turn evolved from an ancestor with 47 leg pairs, which in turn evolved from an ancestor with 45 leg pairs. [8]

Distribution

This genus is distributed over a large geographic range. [8] Centipedes in this genus are found mainly in tropical and subtropical regions of south and east Asia, with some also found in temperate areas and in the Americas. [2] Maximum diversity in terms of species occurs in the region of Japan and southeast Asia. [8]

Species

There are about 140 valid species, [2] including: [5]

Related Research Articles

Nannarrup is a genus of soil centipedes in the family Mecistocephalidae; this genus includes a single species, Nannarrup hoffmani, also known as Hoffman's dwarf centipede. This centipede was discovered in Central Park in New York City and was the first new species to be discovered in that park in more than a century. This species is the smallest species in the family Mecistocephalidae, reaching only 10.3 mm in length, and has only 41 pairs of legs, the minimum number recorded in this family.

<span class="mw-page-title-main">Mecistocephalidae</span> Family of centipedes

Mecistocephalidae is a monophyletic family of centipedes in the order Geophilomorpha. It is the only family in the suborder Placodesmata. Most species in this family live in tropical or subtropical regions, but some occur in temperate regions. This family is the third most diverse in the order Geophiliomorpha, with about 170 species, including about 130 species in the genus Mecistocephalus.

<i>Geophilus</i> Genus of centipedes

Geophilus is a large, heterogeneous genus of soil centipedes in the family Geophilidae largely considered to be synonymous with Brachygeophilus. The generic name first appeared in Brewster's Edinburgh Encyclopaedia in 1814 as Geophilus electricus. This genus has a Holarctic distribution.

<i>Tygarrup</i> Genus of Mecistocephalidae centipedes

Tygarrup is a genus of centipedes in the family Mecistocephalidae, found mainly in southeast Asia and from the Seychelles to Hawaii. Although species in this genus can have either 43 or 45 leg-bearing segments, most of these species have 45 leg pairs. An undescribed Tygarrup species found in the Andaman Islands has 43 leg pairs. Centipedes in this genus are sometimes melanised in patches, and sternal glands are present the males of most species. These centipedes range from 2 cm to 6 cm in length. Tygarrup javanicus is one of the smallest of the mecistocephalid species and has become an invasive in greenhouses in Europe.

Arrup is a genus of centipedes in the family Mecistocephalidae, native to Europe and Asia as far as Japan. Centipedes in this genus feature small telopodites on the second maxillae, the head and forcipular segment are elongate, the clypeus is almost completely areolate, and the poison glands in adult males are often deep inside the forcipules. These centipedes range from 1 cm to 5 cm in length. All species in this genus have 41 leg-bearing segments. Most are soil-dwellers but Arrup akiyoshiensis is a troglobiont.

Agnostrup is a genus of centipedes in the family Mecistocephalidae, native to Europe and Asia. Centipedes in this genus feature small telopodites without claws on the second maxillae and a robust basal denticle on the forcipular tarsungulum. These centipedes range from 2 cm to 3 cm in length. All species in this genus have 41 leg-bearing segments.

Anarrup is a genus of centipedes in the family Mecistocephalidae, native to Europe and Asia as far as Indonesia. Centipedes in this genus feature a clypeus with areolation and setae limited to a short anterior marginal band; the second maxillae have swollen and densely setose telopodites and a coxosternite divided mid-longitudinally. These centipedes range from 6 cm to 8 cm in length. All species in this genus have 41 leg-bearing segments.

Mecistocephalus lifuensis is a species of soil centipede in the Mecistocephalidae family. This species was first described in 1898 by zoologist Reginald Innes Pocock based on type material found on is Lifou Island in New Caledonia, a French overseas territory in Melanesia. This centipede is notable for featuring 51 pairs of legs rather than the 49 leg pairs usually observed in the genus Mecistocephalus.

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

Dicellophilus carniolensis is a species of soil centipede in the family Mecistocephalidae. This centipede is well known and found in central Europe. This species features 43 pairs of legs, a number rarely found in the family Mecistocephalidae and recorded in only one other genus in this family: In the genus Tygarrup, an undescribed species found in the Andaman Islands also has 43 leg pairs.

Mecistocephalus angusticeps is species of soil centipede in the family Mecistocephalidae. This centipede is found in Kenya, Seychelles, and the Chagos Archipelago. This species features only 47 pairs of legs rather than the 49 leg pairs usually observed in the genus Mecistocephalus.

Krateraspis is a genus of soil centipedes in the family Mecistocephalidae. Centipedes in this genus are found in Central Asia. This genus contains only two species, K. meinerti, with 45 pairs of legs, and K. sselivanovi, with 53 leg pairs. The species K. sselivanovi is notable for featuring 53 leg pairs without any intraspecific variation. This number of legs is rarely observed in the family Mecistocephalidae and also appears to be the maximum number evidently fixed by species in the class Chilopoda.

Mecistocephalus evansi is a species of soil centipede in the family Mecistocephalidae. This centipede is notable for featuring 51 pairs of legs rather than the 49 leg pairs usually observed in the genus Mecistocephalus. This species was first described by the French myriapodologist Henry W. Brolemann in 1922. He based the original description of this species on a single female specimen found in the Maysan governorate on the Tigris river in Iraq.

Krateraspis sselivanovi is a species of soil centipede in the family Mecistocephalidae. This centipede is found in Kyrgyzstan, Tajikistan, and Uzbekistan. This species is notable for featuring 53 leg pairs without any intraspecific variation. This number of legs is rarely observed in the family Mecistocephalidae and also appears to be the maximum number evidently fixed by species in the class Chilopoda.

Mecophilus tupiniquim is a species of soil centipede in the subfamily Aphilodontinae, a clade formerly known as the family Aphilodontidae but now deemed a subfamily within the family Geophilidae. This centipede is notable for its small size and modest number of legs. This species is found in Brazil.

Escaryus is a genus of soil centipedes in the family Schendylidae. These centipedes are notable as schendylids adapted to colder temperatures and restricted to cool climates and high latitudes. With more than 30 species, this genus is easily the largest group of such centipedes in the family Schendylidae. Most schendylids are limited to tropical or subtropical regions.

Mecistocephalus nannocornis is a species of soil centipede in the Mecistocephalidae family. This centipede has only 45 pairs of legs, the minimum number recorded in the genus Mecistocephalus. This centipede was the second species in this genus to be discovered with such a modest number of legs.

Mecistocephalus diversisternus is a species of soil centipede in the family Mecistocephalidae. This centipede is notable for featuring 57 or 59 pairs of legs rather than the 49 leg pairs usually observed in the genus Mecistocephalus. This centipede is one of only a few species in the genus Mecistocephalus or in the family Mecistocephalidae with more than 55 leg pairs. This centipede is also one of only a few species in this family to exhibit any variation in leg number among specimens. This species is found from the island of Honshu in Japan to Taiwan.

Mecistocephalus japonicus is a species of soil centipede in the family Mecistocephalidae. This centipede is notable for featuring 63 or 65 pairs of legs rather than the 49 leg pairs usually observed in the genus Mecistocephalus. This centipede is one of only a few species in the genus Mecistocephalus or in the family Mecistocephalidae with more than 55 leg pairs. This centipede is also one of only a few species in this family to exhibit any variation in leg number among specimens. This species is found from the island of Honshu in Japan to Taiwan.

Mecistocephalus smithii is a species of soil centipede in the family Mecistocephalidae. This centipede is notable for featuring 59 pairs of legs rather than the 49 leg pairs usually observed in the genus Mecistocephalus. This centipede is one of only a few species in the genus Mecistocephalus or in the family Mecistocephalidae with more than 55 leg pairs. This centipede is also notable as the first Mecistocephalus species discovered in China.

References

  1. ↑ Newport, G (1843). "On some new genera of the class Myriapoda". Proceedings of the Zoological Society of London. 10 (1842): 177–181 [178].
  2. 1 2 3 4 5 6 7 8 9 Bonato, Lucio; Edgecombe, Gregory D.; Zapparoli, Marzio (2011). "Chilopoda – Taxonomic overview". In Minelli, Alessandro (ed.). The Myriapoda. Volume 1. Leiden: Brill. pp. 363–443 [432–433]. ISBN   978-90-04-18826-6. OCLC   812207443.
  3. 1 2 3 4 5 6 Bonato, L.; Minelli, A. (2004). "The centipede genus Mecistocephalus Newport 1843 in the Indian Peninsula (Chilopoda Geophilomorpha Mecistocephalidae)". Tropical Zoology. 17 (1): 15–63 [16, 20, 56]. Bibcode:2004TrZoo..17...15B. doi:10.1080/03946975.2004.10531198. ISSN   0394-6975. S2CID   85304657.
  4. ↑ Newport, G. (1843). "On some new genera of the class Myriapoda". Proceedings of the Zoological Society of London. 10 (1842): 177–181 [177–178] – via Biodiversity Heritage Library.
  5. 1 2 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 Newport, 1843". ChiloBase 2.0 – A World Catalogue of Centipedes (Chilopoda). Retrieved 2024-06-08.
  6. ↑ 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]. doi:10.11646/zootaxa.1396.1.1. ISSN   1175-5334.
  7. ↑ 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.
  8. 1 2 3 4 5 6 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 [543, 545–546, 549–552, 554]. Bibcode:2003SysEn..28..539B. doi:10.1046/j.1365-3113.2003.00217.x. ISSN   0307-6970.
  9. ↑ Evans, W. Edgar; Brolemann, Henry W. (1923). "VI.—Myriapods collected in Mesopotamia and N.W. Persia". Proceedings of the Royal Society of Edinburgh. 42: 54–74. doi:10.1017/S0370164600023841. ISSN   0370-1646.
  10. ↑ Minelli, Alessandro (2020). "Arthropod Segments and Segmentation – Lessons from Myriapods, and Open Questions" (PDF). Opuscula Zoologica (Budapest). 51 (S2): 7–21 [10]. doi:10.18348/opzool.2020.S2.7. S2CID   226561862.
  11. ↑ 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.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.