Wellstenhelia qingdaoensis (Ma & Li, 2011) comb. nov.

(Figs. 24–29)

Synonymy. Delavalia qingdaoensis sp. nov. – Ma & Li 2011, p. 1087, figs. 1–8.

Specimens examined. One female dissected on one slide (collection number NIBRIV0000232685), one male dissected on one slide (collection number NIBRIV0000232686), three females together on one SEM stub (collection number NIBRIV0000232687), 20 females and five copepodids in ethanol (collection number NIBRIV0000232688), 11 females destroyed for DNA sequence (one successful amplification, Code 0113), South Korea, South Sea, Gwangyang Bay, sampling station 15, muddy sediments, 34.890139°N 127.795111°E, 18 November 2012, leg. K. Kim (Fig. 1) .

One female destroyed for DNA sequence (amplification unsuccessful), South Korea, South Sea, Gwangyang Bay, sampling station 12, muddy sediments, 34.951389°N 127.734361°E, 18 November 2012, leg. K. Kim (Fig. 1) .

One female destroyed for DNA sequence (amplification unsuccessful), South Korea, South Sea, Gwangyang Bay, sampling station 14, muddy sediments, 34.924333°N 127.852333°E, 18 November 2012, leg. K. Kim (Fig. 1) .

One female destroyed for DNA sequence (amplification unsuccessful), South Korea, South Sea, Gwangyang Bay, sampling station 17, muddy sediments, 34.824222°N 127.787750°E, 18 November 2012, leg. K. Kim (Fig. 1)

Redescription. Female (based on six examined specimens). Body length from 523 to 611 µm. Body segmentation, colour, nauplius eye, hyaline fringes, integument thickness and surface appearance as in Wellstenhelia calliope sp. nov., including minute sparse pits visible only on highest magnifications on scanning electron microscope (for example, see Fig. 28D). Most somite ornamentation also similar to Wellstenhelia calliope, and presumed homologous pore and sensilla also numbered with same Arabic numerals (see Figs. 24A, B, C, D 25A, B) to allow easier comparison. Habitus (Figs. 24A, B, 27A, 28A) more robust, with prosome/urosome length ratio about one, body length/width ratio 3.1, and cephalothorax twice as wide as genital double-somite.

Rostrum (Figs. 24C, 27B) with slightly narrower tip than in Wellstenhelia calliope (arrowed in Fig. 24C), but without any other difference in shape or ornamentation.

Cephalothorax (Figs. 24A, B, 27A, 28B) about 0.9 times as long as wide; represents 26% of total body length. Surface of cephalothoracic shield with 36 paired or unpaired sensilla and pores, most of which probably homologous to those in Wellstenhelia calliope (indicated with Arabic numerals in illustrations) and Wellstenhelia clio (indicated with currency symbols in illustrations), but six pores and sensilla missing (nos. 14, 19, 21, 33, 34, 35); absolute and relative positions of some pores and sensilla different; posterior dorsal sensilla no. 40 paired.

Pleuron of second pedigerous somite (Figs. 24D, 28C, D) ornamented as in Wellstenhelia calliope, except lateral pair of sensilla no. 48 (arrowed in Fig. 24D) and anterior pair of pores no. 43 missing.

Pleurons of third pedigerous somite (Figs. 24A, B, 28C), fourth pedigerous somite (Figs. 24A, B, 28C), and first urosomite (Figs. 24A, B, 27C, 28C) as in Wellstenhelia calliope .

Genital double-somite (Figs. 24A, B, 25A, 27C) as in Wellstenhelia calliope, except anterior part even more inflated laterally, forming spiniform chitinous processes, central part even more constricted, only four large dorsal sensilla present in anterior part (arrowed in Fig. 24B), and ventral pair of sensilla no. 73 much more widely spaced (arrowed in Fig. 25A).

Last threeurosomites (Figs. 24A, B, 25A, B, 27E, 28E) as in Wellstenhelia calliope, except anal somite slightly more elongated and with more slender and denser spinules along dorsal distal margin (arrowed in Fig. 25B).

Caudal rami (Figs. 24A, B, 25A, B, C, 27D, 29F) shape, armature and most ornamentation as in Wellstenhelia calliope, except central part of inner margin without spinules (arrowed in Fig. 25B, but see also Fig. 29F), posterior ventral pore no. 83 missing, principal apical setae strongly fused basally (arrowed in Fig. 25B), and middle apical seta inflated and in most specimens terminates bluntly (arrowed in Fig. 25C), i.e. shorter than outer apical seta; rami about twice as long as anal somite, nearly cylindrical, 4.3 times as long as wide (ventral view), slightly divergent, and with space between them about one ramus width.

Antennula (Figs. 24E, 27B), antenna (Fig. 29B), labrum, paragnaths, mandibula, maxillula, maxilla, and maxilliped as in Wellstenhelia calliope .

Swimming legs (Figs. 24F, 25D, 29C, D) segmentation, ornamentation, armature, and even proportions of various armature elements as in Wellstenhelia calliope, except spinules in proximal row on coxae much longer (arrowed in Fig. 24F) and first endopodal segments without anterior pore.

Fifth leg (Figs. 24A, B, 25A, E, 29E) segmentation, general shape, number of armature elements, and most ornamentation as in Wellstenhelia calliope, except second endopodal seta from inner side proportionately much shorter (arrowed in Figs. 24A, 25A, E), basal part of exopod somewhat narrower (arrowed in Fig. 25E), and another pore visible on posterior side of exopod. Length ratio of endopodal setae, starting from inner side, 1: 1: 1.9: 1.6. Length ratio of exopodal setae, starting from inner side, 1: 0.4: 0.4: 1: 0.7: 0.6.

Sixth leg as in Wellstenhelia calliope .

Male (based on allotype and three paratypes). Body length from 466 to 492 µm. Habitus, colour, rostrum, shape and ornamentation of cephalothorax, all pedigerous somites, ornamentation of last threeurosomites (Fig. 26A, B), caudal rami (Fig. 26A, B), antenna (Fig. 29A), labrum (Fig. 27F), paragnaths, mandibula (Fig. 27F), maxillula (Fig. 27F), maxilla (Fig. 27F), maxilliped (Fig. 27F), first swimming leg, third swimming leg, and coxae, bases, and exopods of second and fourth (Fig. 28F) swimming legs as in female. Prosome/urosome ratio 1.1, greatest width at posterior end of cephalothorax, body length/width ratio about 3.6; cephalothorax twice as wide as genital somite in dorsal view. Genital somite and third urosomite not fused.

First urosomite (Fig. 26A, B) slightly narrower and longer than in female but also with three pairs of sensilla (nos. 64, 65, 66) and one pair of pores (no. 63).

Genital somite (Fig. 26A, B) as in Wellstenhelia calliope, except lateral pore no. 68 situated somewhat closer to ventral side.

Third urosomite (Fig. 26A, B) as in Wellstenhelia calliope, except ventral row of spinules not interrupted between sensilla pair no. 73 (arrowed in Fig. 26B), and those sensilla also more widely spaced.

Antennula (Fig. 26C, D) shape, segmentation, and most armature and ornamentation as in Wellstenhelia calliope, except much shorter generally, especially ultimate segment (arrowed in Fig. 26D), and third and fourth segments wiht one and two additional setae respectively; setal fomula thus 1.11.7+ae.9+ae.1.2.1.4.6+ae.

Endopod of second swimming leg (Fig. 26E) with second and third segments fused, as in Wellstenhelia calliope, but with only two apical elements (arrowed in Fig. 26E).

Endopod of fourth swimming leg (Fig. 26F) with inner seta on first segment slender and plumose, as in Wellstenhelia calliope, but outer apical element on third segment transformed into powerful claw (arrowed in Fig. 26F).

Fifth leg (Fig. 26A) shape, armature, and ornamentation as in Wellstenhelia calliope, except inner exopodal element much stronger and longer (arrowed in Fig. 26A); length ratio of exopodal armature elements, starting from inner side 1: 0.7: 0.4.

Sixth leg (Fig. 26A, B) as in Wellstenhelia calliope, except middle seta somewhat stronger); length ratio of armature elements, starting from inner side, 1: 1.5: 1.

Variability. The middle apical caudal seta can be more or less inflated in female and more or less fused with outer apical seta, and distal part can be completely missing or present as a short slender extension of the inflated part. This seta is less noticeably inflated in males. All other features are extremely conservative.

Morphological affinities. Autapomorphies of Wellstenhelia qingdaoensis (Ma & Li, 2011) comb. nov. include slender and dense dorsal spinules along distal margin of the anal somite (Fig. 25B), inflated inner principal caudal seta (Fig. 25C), long spinules on the first leg coxa (Fig. 24F), second seta from inner side on the female fifth leg endopod short (Fig. 25E), and very narrow base of the female fifth leg exopod (Fig. 25E). Other unique features include the reduced armature of the male second leg endopod (Fig. 26E) and transformed inner apical seta on the male fourth leg endopod (Fig. 26F), but as mentioned above, males or male characters are unknown in four congeners. The long and slender caudal rami of Wellstenhelia qingdaoensis are superficially similar to those of Wellstenhelia calliope sp. nov. (see above), but they lack spinules along the posterior part of the inner margin in the former species, as well as the posterior pair of ventral pores (no. 83). As mentioned in the affinities section of Wellstenhelia calliope (see above) morphological differences between these two species are numerous, and it is quite probable that the elongated caudal rami evolved convergently in these two species. All other congeners have much shorter caudal rami than Wellstenhelia qingdaoensis, and each can be distinguished additionally from it by several other differences in the ornamentation of somites or other micro-characters. In fact, this species has a somewhat isolated position in the genus. The Mediterranean Wellstenhelia bocqueti (Soyer, 1971) comb. nov. has basally confluent principal caudal setae, similar to those of Wellstenhelia qingdaoensis, but the former species has much shorter caudal rami, differently shaped female fifth leg, and shorter ventral rows of spinules on urosomites.