Notopterophorus Leuckart, 1859

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 : 135-136

Genus Notopterophorus Leuckart, 1859

Diagnosis. Female body with large brood pouch, often extending from third pedigeroussomite backwards, incorporating fourth pedigerous somite and most of fifth. First to third or fourth pedigerous somites each typically with paired dorsal wing-like extensions; extensions often terminating in slender tapering process(es). Free urosome 5-segmented in female consisting of genital somite and 4 abdominal somites. Urosome 6-segmented in male. Anal somite often with processes. Caudal rami curved; armed with 4 claws and 2 setae. Rostrum welldeveloped. Female antennule 8- or 9-segmented, with first and second segments typically broader than distal segments: segmental fusion pattern I-II, III-XI, XII-XIV, XV-XVI, XVII-XX, XXI-XXIII, XXIV, XXV, XXVI-XXVIII; or with additional compound segment XII-XVI in 8-segmented species. Male antennule typically 9-segmented; non-geniculate. Antenna consistingof coxa, basis, and 2-segmented endopod or with allobasis incorporating first endopodal segment and 1-segmented free endopod; exopod reduced to seta or absent. Mandible with well developed coxal gnathobase and biramous palparmedwith 1 setaon basis, 5 setaeon exopod, and 4 and 10 setae on first and second endopodal segments, respectively (3 and 8 in N. glabrus sp. nov.). Maxillule with 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 variable setation on first and second segments; unsegmented in some species. Maxilla indistinctly 5-segmented, syncoxa enditic formula 4, 1, 2, 3, or reduced; basis with claw plus 2 setae, 3-segmented endopod with setal formula 1, 1, 3 or 4. Maxilliped 3-segmented and armed with 9 setae on first segment, 1 on second and 4 on third (rarely 3). Legs 1–4 biramous with 3-segmented exopods and 2-segmented endopods; first exopodal segment of legs 2–4 typically elongate; armature formula of female typically:

Leg 5 consistingof large protopod fused to somite and free exopodal segment armed with 2 elements.

Type species. Notopterophorus elongatus Buchholz, 1869 .

Remarks. Notopterophorus is a problem genus; indeed, itliesatthefocalpointof aclusterof nomenclatural and taxonomic problems. Firstly, as noted by many previous authors, Notopterophorus of Costa, 1840 is a nomen nudum. Sars (1921) attributed this genus to Costa (1852) as this publication included a plate of figures some of which clearly represented a Notopterophorus . Illg & Dudley (1965) considered this issue at some length and finally attributed the genus Notopterophorus to Leuckart (1859). This treatment was followed by Gotto (1993), for example, but has not been universally adopted. Secondly, species delimitation is an historic problem within the genus Notopterophorus . Illg & Dudley (1965) devoted considerable effort into the careful analysis of the nominal species and their diagnostic features in their study of the notodelphyids from the vicinity of Naples. They recognized five species as valid, providing redescriptions of three of them: N. elongatus Buchholz, 1869 , N. papilio Hesse, 1864 , and N. elatus Giesbrecht, 1882 , and treating two others as valid, N. auritus ( Thorell, 1859) and N. micropterus Sars G.O., 1921 . The painstaking study of Illg & Dudley (1965) also established numerous synonymies between early species records that were incompletely or inadequately described by Costa (1852), Hesse (1864, 1869), Buchholz (1869), Leuckart (1859), Aurivillius (1882), Kerschner (1879) and others. In his synoposis of the British fauna Gotto (1993) included four species, N. auritus , N. elatus , N. elongatus , and N. papilio . Currently five species are listed as valid in the World of Copepoda ( Walter & Boxshall, 2020): N. micropterus , N. auritus , N. elongatus , N. papilio and N. elatus —all widely recorded in European waters.

Various characters, including the positions of the 2 caudal setae, the setation of particular appendages, and even the relative lengths of setae and spines on these appendages, have been highlighted as useful in species discrimination. However, after careful comparison between the appendages of the described species, we have failed to find reliable differences between species. Our comparisons excluded N. cristatus Hesse, 1871 which is a species inquirendum. Some characters have been recognized as variable: for example, the endopod of the maxillule has been described as having either 6 or 7 setae. Sars (1921) figured the 7 (4+3) setae condition of the endopod in N. auritus , but only 6 setae were present in one of our examined specimens. Illg & Dudley (1965) reported that the setation could be either 6 or 7 in N. papilio and N. elongatus . In an individual of N. papilio we observed the 6 and 5 setae conditions on different sides of the body. Given our current inadequate state of knowledge concerning variability exhibited within this genus, we here treat this variability as infraspecific.