Diacyclops huntervalleyensis, Karanovic, 2024

Karanovic, Tomislav, 2024, Six new species of Diacyclops (Copepoda: Cyclopoida) from Australia, Zootaxa 5541 (2), pp. 101-143 : 132-135

Diacyclops huntervalleyensis sp. nov.

( Figs. 1F , 26 , 27 )

urn:lsid:zoobank.org:act:D142C1FE-BE38-4935-9261-0F360A8EBEC6

Type locality. Australia, New South Wales, Hunter Valley , bore80071,sample no.2HD45, 32.006601°S 150.86074°E, 5 July 2005, collected by P. Hancock.

Holotype. Adult female dissected on one microscope slide.

Paratypes. One male and 2 females from type locality dissected on 1 microscope slide each; 5 males, 10 females, and 2 copepodids from type locality in 1 alcohol vial; 1 male and 3 females from bore 80439, Hunter Valley , New South Wales, 32.04921°S 150.94307°E, sample no. 2HD52, 6 July 2005, collected by P. Hancock, on 1 SEM stub (row no. 2), together with five other species described here ; 8 males, 13 females, and 2 copepodids from bore 80439 (see above) in 1 alcohol vial; 72 males, 104 females, and 61 copepodids from bore 80439 (see above), but collected on 3 April 2005 by P. hancock, in 1 alcohol vial.

Etymology. The species name refers to its type locality, Hunter Valley, which was named after Hunter River, which was in turn named in 1797 after Captain John Hunter, who was at that time Governor of the British colony in New South Wales. It is an adjective for place, made with the Latin suffix “ -ensis ”.

Diagnosis. Female. Body length from 340 to 360 µm. Habitus ( Figs. 1F , 27A ) slender, 3.4 times as long as wide, with prosome/urosome ratio of 1.2, and cephalothorax twice as wide as genital double-somite in dorsal view. Integument on all somites ( Fig. 27A, C, F ) thin and smooth, with light bacterial cover; general distribution of spinules and cuticular pores on somites as in D. leijsi . Hyaline fringes of prosomites ( Fig. 27A ) and urosomites ( Fig. 26A ) smooth. Genital double-somite ( Figs. 26A , 27A ) slightly wider than long in ventral view, widest at first third of its length and gradually tapering posteriorly, widest part about 1.5 times as wide as posterior margin; seminal receptacle smallest of all species described here, almost without posterior part, in shape most similar to that in D. tomlinsonae ; copulatory pore small and located at about 2 fifths of somite length; copulatory duct wide, long, and well-sclerotized. Anal somite ( Figs. 26A , 27C ) with large spinules along ventral and lateral margins. Caudal rami ( Figs. 26A , 27D ) of medium length and stout, narrowly spaced, about 3 times as long as wide and about twice as long as anal somite; principal terminal setae with breaking planes, inner one about 0.7 times as long as entire urosome and 1.35 times as long as outer one; dorsal seta about 1.25 times as long as caudal ramus, 3.1 times as long as innermost terminal seta, and 3.4 times as long as outermost terminal seta. Antennula ( Fig. 26B ) 10-segmented, half as long as cephalothorax, with single aesthetasc on penultimate segment and setae formula 8.4.8.5.2.2.2.2.2.8; ultimate segment about 1.3 times as long as wide. Antenna ( Figs. 26C , 27B ) 5-segmented, without exopodal seta, with setae formula 0.1.1.5.7; second segment about 1.6 times as long as fifth segment. Labrum ( Fig. 24E ) with 2 diagonal rows of 8 slender spinules each on anterior surface and row of minute spinules on blunt lateral conrers; cutting edge slightly concave, with 15 sharp teeth. Mandibula ( Fig. 26E ), maxillula ( Figs. 26F , 27B ), maxilla ( Figs. 26G , 27B ), and maxilliped ( Figs. 26H , 27B ) as in D. tomlinsonae . Shape, segmentation, and armature of swimming legs ( Figs. 26I, J, K, L, M, N, O, P , 27B, E ) as in D. tomlinsonae , except first exopodal segment of second to fourth legs with inner seta; third endopodal segment of fourth leg 1.3 times as long as wide; its outer spine about as long as segment and twice as long as inner spine. Fifth leg ( Fig. 26A ) and sixth leg ( Fig. 27F ) as in D. tomlinsonae .

Male. Body length from 330 to 355 µm. Habitus and urosome ( Fig. 26R ) slightly slenderer than in female; free genital somite ( Fig. 26R ) less than 1.3 times as wide as subsequent urosomite, with small ovoid spermatophores. Ornamentation of cephalothorax, free prosomites, and last 3 urosomites as in female. Caudal rami ( Fig. 26R ) slightly slenderer than in female, but proportion of setae without any significant difference. Antennula ( Fig. 26S ) segmentation, armature, and proportions as in D. tomlinsonae ; penultimate segment about as long as wide.Antenna, labrum, mandibula, maxillula, maxilla, maxilliped, all swimming legs ( Fig. 26T ), and fifth leg ( Fig. 26R ) as in female. Sixth leg ( Fig. 26R ) similar to that in D. tomlinsonae , but cuticular plate shorter and with nearly straight posterior margin.

Figures

FIGURE 1. Habitus in dorsal view of holotype females of all six new species: A, Diacyclops leijsi sp. nov.; B, D. eberhardi sp. nov.; C, D. ballaballaensis sp. nov.; D, D. hancocki sp. nov.; E, D. tomlinsonae sp. nov.; F, D. huntervalleyensis sp. nov. Scale bar 100 µm.

FIGURE 24. Diacyclops tomlinsonae sp. nov., scanning electron micrographs, paratype female 2, ventral:A, habitus; B, genital double-somite; C, anal somite and anterior part of caudal rami; D, posterior part of right caudal ramus; E, mouth appendages; F, third exopodal segment of fourth swimming leg.

FIGURE 26. Diacyclops huntervalleyensis sp. nov., line drawings, A–P, holotype female; R–T, paratype male 1: A, urosome, ventral; B, antennula; C, antenna; D, labrum; E, cutting edge of mandibula; F, maxillilar palp; G, basis of maxilla; H, distal part of maxilliped; I, third endopodal segment of first swimming leg; J, exopod of first swimming leg; K, third endopodal segment of second swimming leg; L, exopod of second swimming leg; M, third endopodal segment of third swimming leg; N, exopod of third swimming leg; O, third endopodal segment of fourth swimming leg; P, exopod of fourth swimming leg; R, urosome, ventral; S, distal part of antennula; T, third endopodal segment of fourth swimming leg. Scale bar 50 μm.

FIGURE 27. Diacyclops huntervalleyensis sp. nov., scanning electron micrographs, A & B, paratype female 1, ventral; C–E, paratype female 2, ventral; F, paratype female 3, lateral: A, habitus; B, mouth parts; C, anal somite and anterior part of caudal rami; D, posterior part of caudal rami; E, distal part of fourth swimming leg; G, sixth leg.