Pseudotachidiidae
| Pseudotachidiidae | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Copepoda |
| Order: | Harpacticoida |
| Family: | Pseudotachidiidae |
Pseudotachidiidae is a family of marine benthic copepods in the order Harpacticoida.[1] Members of this family are small, typically ranging from about 0.2 to 1.5 mm in length, and are adapted to living in marine sediments, including both shallow coastal and deep-sea environments.[2][3] Pseudotachidiidae are primarily deposit feeders in sedimentary habitats and form an important component of meiofaunal communities, particularly in deep-sea settings where they can be among the dominant harpacticoid families.[2]
Morphology
Pseudotachidiidae exhibit typical harpacticoid body form: elongate, dorsoventrally flattened, with a cephalothorax and slender urosome ending in caudal rami. Diagnostic characters include antennule segmentation, setation patterns on thoracic legs P1–P4, caudal ramus morphology, and pronounced sexual dimorphism in males (especially antennules and fifth legs).[2][4] Female antennules are usually 6–8 segmented; male antennules are often geniculate. Antennae have 1–2 exopodal segments with genus-specific setation. Swimming legs are biramous; deep-sea species frequently show reductions in inner setae on P2–P4 exopods. Caudal rami vary in shape and armature (typically seven setae, sometimes reduced). Mouthparts are adapted for detritivory.[3][2]
Distribution and habitat
The family has a cosmopolitan distribution in marine environments, recorded from intertidal and subtidal sediments to abyssal depths exceeding 5,000 m.[4][2] Species occur in diverse habitats including coastal muds, continental slopes, submarine canyons, abyssal plains, and structured deep-sea substrates. They are particularly diverse and abundant in deep-sea harpacticoid assemblages, often ranking among the most species-rich families alongside Ameiridae, Argestidae, and Ectinosomatidae.[2] Records include the Angola Basin, Weddell Sea, northwestern Pacific abyssal plains, Kara and East Siberian Seas, and coastal waters of South Korea.[3][4]
Taxonomy
The family Pseudotachidiidae was established by Lang in 1936.[5] It currently includes four subfamilies: Danielsseniinae, Donsiellinae, Pseudomesochrinae, and Pseudotachidiinae.[4]
Genera
Selected genera include:[6]
Afrosenia Huys & Gee, 1996 Anapophysia Huys & Gee, 1996 Apodonsiella Hicks, 1988 Danielssenia Boeck, 1873 Donsiella Stephensen, 1936 Leptotachidia Becker, 1974 Paradanielssenia Soyer, 1970 Pseudomesochra T. Scott, 1902 Pseudotachidius T. Scott, 1898
(and numerous additional genera across the subfamilies).
References
- ^ "Pseudotachidiidae Lang, 1936". World Register of Marine Species. Retrieved 2026-03-10.
- ^ a b c d e f Willén, Elsa (2008). "Pseudotachidiidae (Copepoda: Harpacticoida) from the Angola Basin and the Antarctic deep sea, with the description of a new species of Paradanielssenia Soyer, 1970". Organisms Diversity & Evolution. 8 (3): 223.e1–223.e20. doi:10.1016/j.ode.2008.02.001. hdl:10400.3/1690.
- ^ a b c Kim, Jong Guk (2019). "Description of two deep-water copepods of the genus Leptotachidia Becker from the northwestern Pacific (Harpacticoida, Pseudotachidiidae)". ZooKeys. 879: 31–50. doi:10.3897/zookeys.879.34630. PMC 6728393. PMID 31592180.
- ^ a b c d Kim, Jong Guk; Lee, Wonchoel (2021). "New records of Pseudotachidiidae from South Korea, including a key to species of the Pseudomesochrinae (Copepoda: Harpacticoida)". Zootaxa. 5051 (1): 236–266. doi:10.11646/zootaxa.5051.1.16.
- ^ Lang, K. (1936). "Copepoda Harpacticoida". Further Zoological Results of the Swedish Antarctic Expedition, 1901-1903. 3 (3): 1–68.
- ^ "Pseudotachidiidae Lang, 1936". World Register of Marine Species. Retrieved 2026-03-10.