Tianella

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Tianella
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Diplopoda
Order: Chordeumatida
Family: Entomobielziidae
Genus: Tianella
Attems, 1904
Type species
Tianella fastigata
Attems, 1904

Tianella is a genus of millipedes in the family Entomobielziidae. [1] [2] This genus includes eleven species found in Nepal, one species found in Kazakhstan, and one species found in Kyrgyzstan. [3] This genus is notable for including the only species in the order Chordeumatida with 29 segments (counting the collum as the first segment and the telson as the last) in adults. Most species in this genus have 29 segments in adults rather than the 30 segments usually observed in this order. [4]

Contents

Discovery

This genus was first described by the Austrian myriapodologist Carl Attems in 1904 to contain the newly discovered type species T. fastigata , found in Kyrgyzstan. [5] [6] He described this genus as having the usual 30 segments. [5] The American zoologist William A. Shear described three more species in this genus in 1979, T. bobanga , T. lughla , and T. martensi , all found in Nepal, maintaining the original description of this genus as having 30 segments. [7] In 1979, the Russian myriapodologist Sergei I. Golovatch of the Academy of Sciences of the Soviet Union described another species in this genus, T. ornata , found in Kazahkstan. [8] Golovatch originally described T. ornata as having 30 segments. [9]

In 1987, Shear described another four species in this genus, all found in Nepal. He found that the smaller two species, T. daamsae and T. mananga , have only 28 segments as adults, and the larger two, T. ausobskyi and T. gitanga , have 29 segments as adults, a number never recorded before in the order Chordeumatida. [10] In 1988, the French myriapodologist Jean-Paul Mauriès of the Muséum National d'Histoire Naturelle in Paris described another four species, T. jaljalensis , T. katmandua , T. mangsingma , and T. smetanai , all found in Nepal and all featuring only 29 segments as adults. [3]

Furthermore, Mauriès reports that Golovatch reexamined the type specimens of T. ornata and found that adults of that species have 29 segments rather than the 30 segments reported in the original description. Mauriès also examined the type specimens of T. martensi and found them to have 29 segments rather than the 30 segments indicated by the original description by Shear. Mauriès found the holotype of T. fastigata to be too poorly preserved to determine the number of segments and did not examine any specimens of T. bobanga or T. lughla, but he suspects that these species also have 29 segments rather than the 30 segments indicated by the original descriptions. [3] Thus, at least eight Tianella species have 29 segments as adults, two have 28 segments, and the other three were originally described as having 30 segments but may have 29 segments instead.

Description

These millipedes range from 5.2 mm long in the smallest species (T. daamsae) to 13.3 mm long in the largest species (T. ornata). [10] [9] Adults in most species in this genus have 29 segments, and the females of these species have 48 pairs of legs. [3] In males, the eight leg pair is significantly reduced and modified to form the anterior gonopods, and the ninth leg pair become posterior gonopods. [7] [10] Thus, in species with 29 segments, adult males have 46 pairs of walking legs, excluding these two pairs of gonopods. In species with 28 segments, adult females have 46 pairs of legs, and adult males have 44 pairs of walking legs, excluding two pairs of gonopods. [2] [4]

Development

Species in this genus arrive 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, those in the genus Tianella are 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. The available evidence seems to suggest that Tianella species with 29 segments may go through nine stages, as most chordeumatidans do, but add one segment fewer than usual upon entering the seventh stage, leaving these species with one segment fewer than usual in the eighth stage and in the ninth and final stage. [4]

Mauriès found juveniles from four Tianella species representing at least four different stages of development. The earliest stage found in this sample, with 15 segments and 16 leg pairs, matches the fourth stage of development usually observed in chordeumatidans, and another stage found, with 23 segments and 32 leg pairs, matches the sixth stage usually observed. The next stage in Tianella, however, with only 25 segments and 38 leg pairs, has one segment and two leg pairs fewer than usually observed in the seventh stage in chordeumatidans. In the next (and penultimate) stage of development in Tianella, this difference persists, with only 27 segments and 44 leg pairs (rather than the 28 segments and 46 leg pairs usually observed in the eighth stage). Finally, this difference continues into the adult stage of Tianella, with only 29 segments and 48 leg pairs (rather than the 30 segments and 50 leg pairs usually observed in the ninth stage). [4] [3]

Species

This genus includes 13 species: [1]

Related Research Articles

<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">Cleidogonidae</span> Family of millipedes

Cleidogonidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 28, 29, or 30 segments. This family includes the genus Tianella, notable for featuring adult millipedes with 29 segments, a number not found in the adults of any other chordeumatidan species. Adults in most Tianella species have 29 segments, but adults in two have only 28 segments. In the Tianella species with 29 segments, adult females have 48 pairs of legs, as one would expect in adult female chordeumatidans with one segment fewer than the 30 usually found in this order. There are seven genera and at least 140 described species in Cleidogonidae.

<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.

<span class="mw-page-title-main">Trichopolydesmidae</span> Family of myriapods

Trichopolydesmidae is a family of millipedes belonging to the order Polydesmida. This family includes two genera notable for featuring sexual dimorphism in segment number: adult females in these genera have the 20 segments usually found in this order, but adult males have only 19. This family also includes the species Deharvengius bedosae, notable for being among the very few species in this order to feature adults with only 18 segments rather than the 20 segments usually found in polydesmids.

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.

Peterjohnsiidae is a small family of millipedes belonging to the order Chordeumatida. The family was first described in 1987 by Jean-Paul Mauriès. These millipedes range from 3 mm to 8 mm in length and are found in Australia. Species in this family exhibit sexual dimorphism in segment number: adult males have 30 segments, but adult females have 32 segments. In adult males in this family, the gonopod complex involves three leg pairs rather than just the two usually modified into gonopods in this order.

Golovatchiidae is a family of millipedes belonging to the order Chordeumatida. This family contains a single species, Golovatchia magda. This species ranges from 15 mm to 17 mm in length and is found in the Russian Far East. Adult millipedes of this species have 30 segments. In the adult male of this species, the gonopod complex involves three leg pairs rather than just the two that are usually modified into gonopods this order.

Hoffmaneumatidae is a family of millipedes belonging to the order Chordeumatida. This family includes two genera, one (Hoffmaneuma) found in the Russian Far East and the other (Japanoparvus) found in Japan. Millipedes in this family range from 4 mm to 6 mm in length. Adult millipedes in this family have only 28 segments, not the 30 segments usually found in this order. Adult males in this family feature a reduced leg pair 10 in addition to the two pairs normally modified into gonopods in this order. In the adult male of the species Hoffmaneuma exiguum, for example, the gonopod complex derives from all three leg pairs rather than from just the usual two.

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.

Kashmireumatidae is a small family of millipedes belonging to the order Chordeumatida. These millipedes range from 5mm to 14mm in length and are found in East Asia. Adult millipedes in this family have only 26 or 28 segments rather than the 30 segments usually found in this order. In the species Vieteuma topali, adults have 26 segments, whereas in all other species in this family, adults have 28 segments.

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.

Chamaesoma is a monotypic genus of millipede in the family Chamaesomatidae, and Chamaesoma broelemanni is the only species in this genus. 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. This species lives on the surface of the soil and is distributed across most of France and Luxembourg. 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.

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.

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.

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.

Prosopodesmus is a genus of flat-backed millipedes in the family Haplodesmidae. These millipedes are found primarily in Australia and southern Japan. This genus includes the species P. panporus, which is notable for exhibiting sexual dimorphism in segment number: Whereas adult females of this species feature the usual 20 segments usually observed in the order Polydesmida, the adult males of this species feature only 19 segments.

References

  1. 1 2 "MilliBase - Tianella Attems, 1904". www.millibase.org. Retrieved 2024-07-06.
  2. 1 2 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. doi:10.1163/9789004188273_017. ISBN   9789004156128.
  3. 1 2 3 4 5 Mauriès, J P (1988). "Myriapodes du Népal. II. Diplopodes Craspedosomides nouveaux de l'Himalaya et de la région indo-malaise (Craspedosomidea et Chordeumidea)". Revue suisse de zoologie (in French). 95: 3–49 [5–17]. doi: 10.5962/bhl.part.79638 – via Biodiversity Heritage Library.
  4. 1 2 3 4 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.
  5. 1 2 Attems, Carl August Theodor Michael von (1904). "Central - und hoch - asiatische Myriopoden gesammelt im Jahre 1900 von Dr. von Almassy und Dr. von Stummer". Zoologische Jahrbücher (in German). 20: 113–130 [126–128]. doi:10.5962/bhl.part.18578 – via Biodiversity Heritage Library.
  6. ↑ "MilliBase - Tianella fastigata Attems, 1904". www.millibase.org. Retrieved 2024-07-06.
  7. 1 2 Shear, William A. (1979). "Diplopoda from the Nepal Himalayas. Chordeumida with comments on the Asian chordeumid fauna". Senckenbergiana Biologica. 60 (1/2): 115–130 [121–126].
  8. ↑ "MilliBase - Tianella ornata Golovatch, 1979". www.millibase.org. Retrieved 2024-07-06.
  9. 1 2 Golovatch, Sergei I. (1979). "The composition and zoogeographic relationship of the diplopod fauna of Middle Asia. Part 1". Zoologicheskii Zhurnal (in Russian). 58 (7): 987–1001 [987–988].
  10. 1 2 3 Shear, William A. (1987). "Chordeumatid Diplopoda from the Nepal Himalayas, II". Courier Forschungsinstitut Senckenberg. 93: 229–240 [232–235].
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