Notodelphys Allman, 1847

Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), Megataxa 4 (1), pp. 1-6 : 18

Genus Notodelphys Allman, 1847

Diagnosis. Female body with dorsal brood pouch formed by fourth pedigerous somite and largely incorporating fused fifth pedigerous somite. Free urosome 5-segmented in female consisting of genital somite and 4 abdominal somites; 6-segmented in male. Rostrum well-developed. Female antennule typically 15-segmented: segmental fusion pattern I-II, III-V, VI-XI, XII-XIV, XV-XVI, XVII, XXVIII, XIX, XX, XXI, XXII, XXIII, XXIV, XXV, XXVI-XXVIII; segmentation reduced in some species by additional fusions. Male antennule typically 10-segmented; geniculate or non-geniculate according to species; segmental fusion pattern of 10-segmented antennule I-II, III-XI, XII, XIII, XIV, XV-XVI, XVII, XVIII-XX, XXI-XXIII, XXIV-XXVIII.Antenna typically consistingof coxa, basis, and 2-segmented endopodwith compound distal segment (representing fused second and third ancestral segments) bearing terminal claw; exopod typically represented by 2 setae. Mandible with well developed coxalgnathobase and biramous palp armed with 1 seta on basis, 5 setae on exopod, and maximum of 4 and 10 setae (typically 9) on first and second endopodal segments, respectively. Maxillulewith 10 setaeon arthrite, 1 on coxal endite, 2 on epipodite, and 3 on medial margin of basis; exopod unsegmented with 4 setae distally; endopod 2-segmented with 1 and 4 setae on first segment and second segments, respectively; unsegmented in some species. Maxilla indistinctly 5-segmented, syncoxal enditic formula 4, 1, 2, 3, or reduced; basis with claw plus 1 or 2 setae, 3-segmented endopod with setal formula 1, 1, 3/4. Maxilliped 3-segmented and armedwith 8, 9 or 10 setae on first segment, 1 on second and typically 3 on third (rarely 2 or 4 setae). Legs 1–4 biramous with 3- segmented rami; armatureformula typically:

Leg 5 consisting of protopod fused to, or separate from, somite and free exopodal segment armed with 2 elements (1 spineand 1 seta).

Type species. Notodelphys allmani Thorell, 1859 , by subsequent designation (see Remarks).

Remarks. The genus Notodelphys was established by Allman (1847) to accommodate a new species N. ascidicola Allman, 1847 based on material taken from the branchial chamber of “ Ascidia communis “ collected at a number of localities. This species was subsequently recorded by Baird (1850) from coastal waters around the United Kingdom and Ireland. Thorell (1859) described seven new species of Notodelphys but considered that Allman’s species was indeterminable, and he adopted one of his newly described species, N. allmani Thorell, 1859 , as thetype speciesof the genus. Brady (1878) also considered that Allman’s (1847) original description and figures were inadequate to characterise N. ascidicola and commented that it was probable that Allman’s material consisted of a mixture of several speciesof Notodelphys . Brady (1878) also suggested that some of the figures undoubtedlyreferred toanother genus, Ascidicola Thorell, 1859 (family Ascidicolidae ), and he followed Thorell (1859) in discarding the specific name ascidicola and adopting N. allmani Thorell, 1859 as thetype species. Sars (1921) and Illg (1958) also concluded that Notodelphys ascidicola Allman, 1847 was an indeterminable species and adopted N. allmani as the type species. Since 1859 all major contributors to the taxonomy of Notodelphys have followed Thorell (1859) in discarding the specific name ascidicola and recognizing N. allmani Thorell, 1859 , including Buchholz (1869), Brady (1878), Aurivillius (1882), Scott, T. (1888), Carus (1885), Koehler (1890), Canu (1891), Norman & Scott, T. (1906), Sars (1921), Schellenberg (1922), Lang (1948), Stock (1950, 1951), Illg (1958), Bocquet & Stock (1960), Illg & Dudley (1961, 1965), Dudley (1966), and Gotto (1993). Whilst this action should formally have been submitted as a Case to the International Commission on Zoological Nomenclature, we also adopt the 150-year old practice of recognizing N. allmani Thorell, 1859 as the type species in the interests of nomenclatural stability.

Notodelphys is the second largest genus in the family, currently comprising 29 valid species ( Walter & Boxshall, 2020).