Diacyclops tomlinsonae, Karanovic, 2024

Karanovic, Tomislav, 2024, Six new species of Diacyclops (Copepoda: Cyclopoida) from Australia, Zootaxa 5541 (2), pp. 101-143 : 127-132

publication ID	https://doi.org/ 10.11646/zootaxa.5541.2.1
publication LSID	lsid:zoobank.org:pub:86A7CD79-F5A2-4AA6-A6AA-01C0CB64B29C
persistent identifier	https://treatment.plazi.org/id/03E8C55F-9C10-FFC9-FF0B-92F2FBDF612B
treatment provided by	Plazi
scientific name	Diacyclops tomlinsonae
status	sp. nov.

Treatment

Diacyclops tomlinsonae sp. nov.

( Figs. 1E View FIGURE 1 , 22–25 View FIGURE 22 View FIGURE 23 View FIGURE 24 View FIGURE 25 )

urn:lsid:zoobank.org:act:FB1207A7-C319-489E-AA46-D6F85B4D0AEB

Type locality. Australia, New South Wales, Tamworth , bore 93024, sample no. 7 T27 P100-200, 31.26435°S 151.20272°E, 17 July 2007, collected by M. Tomlinson. GoogleMaps

Holotype. Adult female dissected on 1 microscope slide.

Paratypes. One male, 1 female, and 1 copepodid from type locality dissected on 1 microscope slide each; 3 males and 3 females from type locality on 1 SEM stub (row no. 3), together with 5 other species described here; 16 males, 5 females, and 4 copepodids from type locality in 1 alcohol vial; 10 males, 3 females, and 1 copepodid from type locality in 1 alcohol vial; 1 female from type locality, but collected on 30 January 2007 by M. Tomlinson, dissected on 1 microscope slide; 1 male and 3 females from type locality, but collected on 30 January 2007 by M. Tomlinson, in 1 alcohol vial.

Etymology. The species is named after Dr. Moya Tomlinson, Australian Rivers Institute, Griffith University, Nathan, who collected this species and entrusted it to me for identification. The name is a noun in the genitive singular.

Diagnosis. Female. Body length from 355 to 420 µm. Habitus ( Figs. 1E View FIGURE 1 , 24A View FIGURE 24 ) slender, more than 3.1 times as long as wide, with prosome/urosome ratio of about 1.35, and cephalothorax 1.83 times as wide as genital double-somite in dorsal view. Integument on all somites ( Fig. 24A, B, C View FIGURE 24 ) thin and smooth, with almost no bacterial cover; general distribution of spinules and cuticular pores on somites as in D. leijsi . Hyaline fringes of prosomites ( Fig. 24A View FIGURE 24 ) and urosomites ( Figs. 22A View FIGURE 22 , 24B, C View FIGURE 24 ) smooth. Genital double-somite ( Figs. 22A View FIGURE 22 , 24B View FIGURE 24 ) about as long as wide, widest at first quarter of its length and gradually tapering posteriorly, widest part about 1.5 times as wide as posterior margin; seminal receptacle small and butterfly-shaped, posterior part greatly reduced; copulatory pore small and located at about 2 fifths of somite length; copulatory duct narrow, long, and weakly sclerotized. Anal somite ( Figs. 22A View FIGURE 22 , 24C View FIGURE 24 ) with large spinules along ventral and lateral margins. Caudal rami ( Figs. 22A View FIGURE 22 , 24D View FIGURE 24 ) of medium length and stout, narrowly spaced, about 2.75 times as long as wide and about twice as long as anal somite; principal terminal setae with breaking planes, inner one about 0.9 times as long as entire urosome and 1.45 times as long as outer one; dorsal seta about 1.2 times as long as caudal ramus, 2.6 times as long as innermost terminal seta, and 3 times as long as outermost terminal seta. Antennula ( Fig. 22B View FIGURE 22 ) 11-segmented, half as long as cephalothorax, with single aesthetasc on penultimate segment and setae formula 8.4.8.3.2.2.2.2.2.2.8; ultimate segment about 1.4 times as long as wide. Antenna ( Figs. 22C View FIGURE 22 , 24E View FIGURE 24 ) 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 View FIGURE 24 ) with 2 diagonal rows of 8 slender spinules each on anterior surface; cutting edge slightly concave, with 16 sharp teeth between blunt and smooth lateral corners. Mandibula ( Fig. 22D View FIGURE 22 ) similar to that in D. leijsi , but with much shorter dorsalmost seta on cutting edge. Maxillula ( Figs. 22E View FIGURE 22 , 24E View FIGURE 24 ) also similar to that in D. leijsi , but with shorter and slightly inflated coxobasis. Maxilla ( Figs. 22F View FIGURE 22 , 24E View FIGURE 24 ) similar to that in D. leijsi , but with shorter basis; basal claw shorter than strong basal seta. Maxilliped ( Figs. 22G View FIGURE 22 , 24E View FIGURE 24 ) small, slender, with setae formula 2.1.1.2. Shape and segmentation of swimming legs ( Figs. 22H View FIGURE 22 , 23A, B, C, D, E View FIGURE 23 ; 24F View FIGURE 24 ) as in D. leijsi , except exopod of first leg 2-segmented and all legs much shorter; basis of first leg with long outer seta and short inner spine, latter slightly shorter that first endopodal segment; basis of second to fourth legs with slightly shorter outer seta and inner distal corner blunt; all first exopodal segments without inner seta; second exopodal segment of second to fourth legs, all first endopodal segments, and second endopodal segment of first and second legs with single inner seta; second endopodal segment of third and fourth legs with 2 inner setae; ultimate exopodal segments spine formula 3.3.3.3 and setae formula 5.4.4.4; third endopodal segments of first to third leg with 2 inner setae, 1 subapical seta, 1 apical spine, and 1 outer seta; third endopodal segment of fourth leg 1.2 times as long as wide, with 2 inner setae, 2 apical spines, and 1 outer seta; its outer spine about 1.3 times as long as segment and slightly more than twice as long as inner spine. Fifth leg ( Fig. 22A View FIGURE 22 ) shape and segmentation as in D. leijsi , but second segment only 1.4 times as long as wide and about 0.7 times as long as its spine. Sixth leg minute, but with two well-articulated spines; outermost seta half as long as plate width and about 4 times as long as spines.

Male. Body length from 330 to 370 µm. Habitus ( Fig. 25A View FIGURE 25 ) and urosome ( Fig. 23F View FIGURE 23 ) slightly slenderer than in female; free genital somite ( Fig. 23F View FIGURE 23 ) less than 1.3 times as wide as subsequent urosomite, with large ovoid spermatophores filling almost entire somite. Ornamentation of cephalothorax, free prosomites, and last 3 urosomites ( Fig. 23F View FIGURE 23 , 25C, D, F View FIGURE 25 ) as in female. Caudal rami ( Figs. 23F View FIGURE 23 , 25D View FIGURE 25 ) slightly slenderer than in female, but proportion of setae without any significant difference. Antennula ( Figs. 23G View FIGURE 23 , 25B, E View FIGURE 25 ) segmentation and armature same as in D. hancocki , but all segments much shorter; penultimate segment only slightly longer than wide. Antenna, labrum, mandibula, maxillula, maxilla, maxilliped, all swimming legs ( Fig. 23H View FIGURE 23 ), and fifth leg ( Fig. 23F View FIGURE 23 ) as in female. Sixth leg ( Figs. 23F View FIGURE 23 , 25C, F View FIGURE 25 ) almost perfectly semicircular, outermost seta about 2.2 times as long as central seta, which in turn about 3.3 times as long as minute innermost spine.

Variability. One paratype female from bore 93024, collected on 30 January 2007, had a slightly shorter outer apical spine on the third endopodal segment of the fourth swimming leg ( Fig. 23E View FIGURE 23 ).