Biology:Halacaridae
| Halacaridae | |
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| Agauopsis brevipalpus | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Order: | Trombidiformes |
| Superfamily: | Halacaroidea |
| Family: | Halacaridae Murray, 1877 |
Halacaridae is a family of meiobenthic mites found in marine, brackish, and freshwater habitats around the world. It includes more than 1100 described species belonging to 64 genera [1][2] It is the largest marine radiation of arachnids.[3]
Description and life cycle
Halacarids have four pairs of legs (as adults and nymphs; see below), of which the first two pairs point forwards and the last two pairs point backwards. This is a synapomorphy of the group. Another synapomorphy are four plates on the dorsal surface of the body, except for several genera with reduction of certain plates.[4]
The life cycle of halacarids consists of egg, larva, 1-3 nymphal stages (protonymph->deutonymph->tritonymph) and adult. Additionally, between each of the free-living stages (i.e. except for the egg) is a quiescent pupal stage.[5]
- Eggs are usually deposited by an adult female in a substrate, with the help of an ovipositor.
- Larvae have three pairs of legs, with each leg five-segmented, and lack a genital plate.
- Protonymphs have four pairs of legs (as do all following stages), of which the fourth pair is five-segmented, and they usually have a distinct genital plate.
- Deutonymphs and tritonymphs have each leg six-segmented.
- Adults are often similar to the last nymphal stage, but they have an ovipositor (if female) or spermatopositor (if male).
Like mites in general, halacarids have a pair of palps. The palps usually have four segments each, but they are three-segmented in Simognathus and just two-segmented in Acaromantis.[3]
Halacarids of subfamily Copidognathinae have just a single nymphal stage. Additionally, the number of genital papillae is reduced to a single pair.[3]
The subfamily Rhombognathinae, which is algivorous, can be recognised by the dark green or almost black pigment inside their digestive system. This pigment is partially digested chlorophyll from algae.[3]
Ecology
Halacaridae occur in various habitats including sandy beaches, tidal sediment, interstitial spaces, hydrothermal vents, mangroves, salt marshes and on larger animals.[2][6] They spend their entire lives on a substrate such as attached algae or sand.[3]
Most species and genera are predators, though Rhombognathinae are instead algivores.[3] In freshwater halacarids, some species are restricted to crayfish gill chambers, implying a parasitic lifestyle, while Lobohalacarus weberi is a scavenger that feeds on dead nematodes and oligochaetes but not on live ones.[7]
Phylogeny
Recent analyses place Halacaridae as the sister group to Parasitengona.[8][9] Within the group, algivorous Rhombognathinae consists of two lineages (Rhombognathus+Isobactrus and Rhombognathides+Metarhombognathus), meaning the habit of algivory has evolved two independent times.[3]
Genera
References
- ↑ Durucan, Furkan (2018). "New record of the genus Scaptognathus (Acari: Halacaridae) from Antalya with a checklist of marine halacarid mites of Turkey". Turkish Journal of Zoology 42 (4): 499–507. doi:10.3906/zoo-1803-6.
- ↑ 2.0 2.1 Bartsch, Ilse (2009). "Checklist of marine and freshwater halacarid mite genera and species (Halacaridae: Acari) with notes on synonyms, habitats, distribution and descriptions of the taxa". Zootaxa 1998: 1–170. doi:10.11646/zootaxa.1998.1.1. https://www.mapress.com/zootaxa/2009/f/z01998p170f.pdf.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Pepato, Almir R.; Vidigal, Teofânia H.D.A.; Klimov, Pavel B. (2018). "Molecular phylogeny of marine mites (Acariformes: Halacaridae), the oldest radiation of extant secondarily marine animals" (in en). Molecular Phylogenetics and Evolution 129: 182–188. doi:10.1016/j.ympev.2018.08.012. PMID 30172010.
- ↑ Harvey, MS (1989). "Pezidae, a new freshwater mite family from Australia (Acarina : Halacaroidea)". Invertebrate Systematics 3 (6): 771. doi:10.1071/it9890771. ISSN 1445-5226. https://www.researchgate.net/publication/259187157.
- ↑ Bartsch, Ilse (2015-02-17). "The genital area of Halacaridae (Acari), life stages and development of morphological characters and implication on the classification". Zootaxa 3919 (2): 201–259. doi:10.11646/zootaxa.3919.2.1. ISSN 1175-5334. PMID 25781126. http://biotaxa.org/Zootaxa/article/view/zootaxa.3919.2.1.
- ↑ Bartsch, I. (2003). "Mangrove halacarid fauna (Halacaridae, Acari) of the Dampier region, Western Australia, with description of five new species" (in en). Journal of Natural History 37 (15): 1855–1877. doi:10.1080/00222930110089184. ISSN 0022-2933. http://www.tandfonline.com/doi/abs/10.1080/00222930110089184.
- ↑ Proctor, H.C. (2009) (in en), Hydrachnida (Water Mites), Elsevier, pp. 335–345, doi:10.1016/b978-012370626-3.00176-9, ISBN 978-0-12-370626-3, https://linkinghub.elsevier.com/retrieve/pii/B9780123706263001769, retrieved 2022-10-14
- ↑ Pepato, A R; Klimov, P B (2015). "Origin and higher-level diversification of acariform mites – evidence from nuclear ribosomal genes, extensive taxon sampling, and secondary structure alignment" (in en). BMC Evolutionary Biology 15 (1): 178. doi:10.1186/s12862-015-0458-2. ISSN 1471-2148. PMID 26330076.
- ↑ Dabert, Miroslawa; Proctor, Heather; Dabert, Jacek (2016). "Higher-level molecular phylogeny of the water mites (Acariformes: Prostigmata: Parasitengonina: Hydrachnidiae)" (in en). Molecular Phylogenetics and Evolution 101: 75–90. doi:10.1016/j.ympev.2016.05.004. PMID 27150348.
Further reading
- Breene, R.G.; Dean, D. Allen; Edwards, G.B.; Hebert, Blain; Levi, Herbert W.; Manning, Gail (2003). Common Names of Arachnids. Fifth Edition. American Tarantula Society. ISBN 1-929427-11-5.
- Encyclopedia of Entomology. Springer. 2008. ISBN 978-1402062421.
- Jackman, John A. (2002). A Field Guide to Spiders and Scorpions of Texas. Gulf Publishing.
- A Manual of Acarology. 3rd Edition. Texas Tech University Press. 2009. ISBN 9780896726208.
Wikidata ☰ Q1104692 entry
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