Chamaesoma

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Chamaesoma
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Diplopoda
Order: Chordeumatida
Family: Chamaesomatidae
Genus: Chamaesoma
Ribaut & Verhoeff, 1913
Species:
C. broelemanni
Binomial name
Chamaesoma broelemanni
Ribaut & Verhoeff, 1913

Chamaesoma is a monotypic genus of millipede in the family Chamaesomatidae, and Chamaesoma broelemanni is the only species in this genus. [1] This millipede is notable as one of only a few species in the order Chordeumatida with only 26 segments in adults (counting the collum as the first segment and the telson as the last), four fewer segments than typically found in adults this order. [2] This species lives on the surface of the soil and is distributed across most of France and Luxembourg. [3] [4] The genus Chamaesoma and its only species were first described by the German zoologist Karl W. Verhoeff in 1913 based on type material found by the French zoologists Henri Brölemann and Henri Ribaut under wet leaf litter near St. Béat in the Pyrenees in France. [5] [3] [6]

Description

This millipede ranges from brown to gray. [5] This species is notable for its small size: Adult males are only 3.25 mm long, and adult females only 4 mm long. [5] [4] This millipede is one of only a few species in the order Chordeumatida with only 26 segments in adults, the minimum number recorded in this order. Accordingly, the adult female of this species has only 42 pairs of legs, and the adult male has only 40 pairs of walking legs, excluding the eighth and ninth leg pairs, which become gonopods. [7] [2]

This species arrives at a lower number of segments and legs through a process of post-embryonic development that deviates from the anamorphosis usually observed in the order Chordeumatida. Like other species in this order, C. broelemanni is teloanamorphic, adding segments and legs through a series of molts until the adult stage, when the molting stops and the adult emerges with a final number of segments and legs. This species, however, reaches maturity and stops molting one stage earlier, in the eighth stage rather than in a ninth stage. Furthermore, C. broelemanni conforms to the pattern usually observed in most species of Chordeumatida only through the first five stages, then adds one fewer segment than usual upon entering the sixth and seventh stages. Thus, in this process, C. broelemanni goes through stages of development with 6, 8, 11, 15, 19, 22, and 24 segments, before emerging as an adult with 26 segments in the final stage. [7] [2]

This process is the same as that observed in the species Opisthocheiron canayerensis , one of the other species in the order Chordeumatida with only 26 segments in adults, but with one difference. In C. broelemanni, the transformation of legs into gonopods in the male begins in the sixth stage and continues until the eighth and final stage. In O. canayerensis, however, this process does not begin until the seventh stage. [7]

Like other millipedes in the family Chamaesomatidae, Chamaesoma features small paranota. [5] [4] Like most other genera in this family, this genus also features anterior gonopods with well developed telepodites. [4] In this genus, these telepodites are long, smooth, and curved. Unlike most other genera in the same family, however, this genus features body pigmentation. [8]

This genus shares an especially extensive set of traits with Xystrosoma , another genus in the same family. For example, the adult males in both genera feature anterior gonopods with angiocoxites that are separate rather than fused, a colpocoxite that is undivided rather than divided in the middle, and no flagella. The posterior gonopods in males of both genera feature a coxa with a medial process and a telepodite with two segments, including a minute distal segment. Furthermore, the eleventh leg pair in males of both genera feature coxal hooks. [8] Moreover, the metazonites in both genera are covered with small lamellae arranged as vertical plates oriented longitudinally. [9]

The millipedes in the genus Chamaesoma can be distinguished from the species in the genus Xystrosoma based on other traits. For example, the lamellae in Chamaesoma are pointed and shaped like triangles. The lamellae in Xystrosoma, however, are rounded and shaped like semicircles. [9] [10]

Related Research Articles

<span class="mw-page-title-main">Xystodesmidae</span> Family of millipedes

Xystodesmidae is a family of millipedes in the suborder Leptodesmidea within the order Polydesmida. The family Xystodesmidae was created by the American biologist Orator F. Cook in 1895 and named after the genus Xystodesmus. This family includes more than 390 known species distributed among 62 genera. Many species, however, remain undescribed: for example, it is estimated that the genus Nannaria contains over 200 species, but only 25 were described as of 2006. By 2022, 78 species in Nannaria have been described.

<span class="mw-page-title-main">Chordeumatida</span> Order of millipedes

Chordeumatida is a large order of millipedes containing more than 1,400 species. Also known as sausage millipedes, they are found nearly worldwide. Chordeumatida is the largest order in the superorder Nematophora, a group also known as spinning millipedes because their telsons feature spinnerets used to build nests of silk. These millipedes produce this silk to create chambers in which to molt or to lay their eggs.

<span class="mw-page-title-main">Anthroleucosomatidae</span> Family of millipedes

Anthroleucosomatidae is a family of millipedes in the order Chordeumatida. This family includes more than 100 species distributed among 40 genera. This family has a mostly Holarctic distribution, with the greatest diversity in the area around the Mediterranean sea.

<span class="mw-page-title-main">Craspedosomatidae</span> Family of millipedes

Craspedosomatidae is a family of millipedes in the order Chordeumatida. Most adult millipedes in this family have 30 segments, but some have only 28. There are at least 30 genera and 210 described species in Craspedosomatidae.

<span class="mw-page-title-main">Metopidiotrichidae</span> Family of millipedes

Metopidiotrichidae is a family of millipedes in the order Chordeumatida. This family includes more than 70 species. These millipedes are found in Indochina, Australia, and on Pacific islands from New Zealand to Japan.

Chordeumatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 7 mm to 18 mm in length and are found in Europe. Adult millipedes in this family have either 28 or 30 segments. This family features distinctive sex-linked modifications to the legs in adults: In the adult female, a legless sternite replaces the third pair of legs, and in the adult male, five pairs of legs are modified in the gonopod complex. These modifications are more extensive than those found in other adult males in this order, which often have only two leg pairs modified into gonopods. With the more extensive modifications to the legs in this family, species with the usual 30 segments feature adult females with only 49 leg pairs and adult males with only 45 pairs of walking legs, and species with only 28 segments feature adult females with only 45 leg pairs and adult males with only 41 pairs of walking legs.

Speophilosomatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes are found in Japan and range from 4 mm to 6 mm in length. Adult millipedes in this family are notable for being among the few in this order with only 26 segments instead of the 30 usually found in chordeumatidans. The adult males in this family are also notable for involving three leg pairs in the gonopod complex rather than the two pairs typically modified into gonopods in this order.

Chamaesomatidae is a family of millipedes belonging to the order Chordeumatida. This family contains 28 species distributed among 11 genera. These millipedes are found in Europe and North Africa.

Entomobielziidae is a family of millipedes belonging to the order Chordeumatida. This family includes 18 species, including 13 in the genus Tianella. Millipedes in this family are found in Romania, central Asia, and the Himalayas.

Trachygonidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 28 or 30 segments.

Opisthocheiridae is a family of millipedes belonging to the order Chordeumatida. This family includes 40 species distributed among seven genera. These millipedes are found in western Europe and Morocco.

Opisthocheiron is a genus of millipedes in the family Opisthocheiridae. These millipedes are found in France and Spain. The French entomologist Henri Ribaut created this genus in 1913 to contain the newly discovered type species Opisthocheiron penicillatum. This genus also includes the cave-dwelling species Opisthocheiron canayerensis, notable as one of only a few species in the order Chordeumatida with only 26 segments in adults, four fewer segments than typically found in adults in this order.

Opisthocheiron canayerensis is a species of millipede in the family Opisthocheiridae. This species is found in France, far inside deep caves. This millipede is notable as one of only a few species in the order Chordeumatida with only 26 segments in adults, four fewer segments than typically found in adults this order.

Haasea hungarica is a species of millipede in the family Haaseidae. This species is a eutroglophile, capable of spending its entire life cycle in a cave but also capable of living on the surface outside of caves. Although these millipedes are often found in caves, this species has also been found on the soil surface in forests.

Lipseuma is a genus of millipedes in the family Kashmireumatidae. This genus contains only two species, the type species L. josianae and its close relative L. bernardi. Both species are troglobites found in caves in China.

Tianella is a genus of millipedes in the family Entomobielziidae. This genus includes eleven species found in Nepal, one species found in Kazakhstan, and one species found in Kyrgyzstan. This genus is notable for including the only species in the order Chordeumatida with 29 segments in adults. Most species in this genus have 29 segments in adults rather than the 30 segments usually observed in this order.

Metamastigophorophyllon is a genus of millipedes in the family Anthroleucosomatidae. This genus includes millipedes found in Azerbaijan, Iran, Russia, and Georgia. All five species in this genus have 31 segments in adults. This genus is notable for including the only species in the order Chordeumatida with 31 segments rather than the 30 segments usually observed in adults in this order.

Neocambrisoma is a genus of millipedes in the family Metopidiotrichidae. Millipedes in this genus are found in Tasmania and New South Wales in Australia. Like other genera in this family, this genus features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, female adults in this genus have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.

Devilliea tuberculata is a species of flat-backed millipedes in the family Xystodesmidae. Like other members of the genus Devillea, this species is limited to caves. This millipede has been found in several caves in the Alpes-Maritimes department of France. This species is notable as the first millipede in the order Polydesmida found to feature more than the 20 segments usually found in this order.

Neocambrisoma raveni is a species of millipede in the family Metopidiotrichidae. These millipedes are found in New South Wales in Australia. Like other species in this family, N. raveni features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, adult females of this species have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.

References

  1. ↑ "MilliBase - Chamaesoma Ribaut & Verhoeff, 1913". www.millibase.org. Retrieved 2024-06-26.
  2. 1 2 3 Enghoff, Henrik; Dohle, Wolfgang; Blower, J. Gordon (1993). "Anamorphosis in Millipedes (Diplopoda) — The Present State of Knowledge with Some Developmental and Phylogenetic Considerations". Zoological Journal of the Linnean Society. 109 (2): 103–234. doi:10.1111/j.1096-3642.1993.tb00305.x.
  3. 1 2 Kime, Richard Desmond; Enghoff, Henrik (2021-09-22). "Atlas of European millipedes 3: Order Chordeumatida (Class Diplopoda)". European Journal of Taxonomy (769): 1–244 [50–51]. doi:10.5852/ejt.2021.769.1497. ISSN   2118-9773.
  4. 1 2 3 4 Enghoff, Henrik; Golovatch, Sergei; Short, Megan; Stoev, Pavel; Wesener, Thomas (2015-01-01). "Diplopoda — taxonomic overview". Treatise on Zoology - Anatomy, Taxonomy, Biology. The Myriapoda, Volume 2: 363–453 [411-412]. doi:10.1163/9789004188273_017. ISBN   9789004188273.
  5. 1 2 3 4 Verhoeff, K.W. (1913). "Zwei neue Gattungen der Trachyzona n. superfam. der Ascospermophora. (Über Diplopoden, 62. Aufsatz.)". Zoologischer Anzeiger (in German). 42 (3): 125–143 [132–135] – via Biodiversity Heritage Library.
  6. ↑ "MilliBase - Chamaesoma broelemanni Ribaut & Verhoeff, 1913". www.millibase.org. Retrieved 2024-06-26.
  7. 1 2 3 David, Jean-François (1989). "Le cycle biologique de Chamaesoma broelemanni Ribaut et Verhoeff, 1913 (Diplopoda, Craspedosomatida) en forêt d'Orléans (France)". Bulletin du Muséum National d'Histoire Naturelle (4) A, Zoologie (in French). 11: 639–647. doi: 10.5962/p.288286 – via Biodiversity Heritage Library.
  8. 1 2 Enghoff, Henrik; Reboleira, Ana Sofia P. S. (2013-11-12). "A new cave-dwelling millipede of the genus Scutogona from central Portugal (Diplopoda, Chordeumatida, Chamaesomatidae)". Zootaxa. 3736 (2): 175–186 [177]. doi:10.11646/zootaxa.3736.2.5. ISSN   1175-5334.
  9. 1 2 Brolemann, H.W. (1935). "Myriapodes Diplopodes (Chilognathes I)" (PDF). Faune de France (in French). 29: 133, 245–247, 260, 263.
  10. ↑ Serra, Antoni; Mauriès, Jean-Paul (2018). "Contribution à la connaissance des Chamaesomatinae, avec description, ontogenèse et écologie de Xystrosoma santllorence n. sp. (Diplopoda, Chordeumida, Craspedosomatidea, Chamaesomatidae)". Bulletin de la Société d'histoire naturelle de Toulouse (in French). 154: 57-70 [59] – via Gallica.
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