Greeffiella sp.

Sergeeva, Nelly G. & Revkova, Tatiana N., 2021, First finding of Greeffiella Cobb, 1922 (Nematoda, Desmoscolecida) in the Black Sea, Ecologica Montenegrina 42, pp. 96-102 : 97-98

Greeffiella sp.

( Figs. 1 , 2 ; Table 1)

Type material: Two females with accession numbers Meib.1.N.1v and Meib.2.N.2v were fixed in gelatinglycerine and deposited in the collection of the Institute of Biology of the Southern Seas of RAS, Sevastopol, Russia .

Type locality: NW of the Black Sea , (lat. 45011 N, long. 32012 E) Crimean Shelf, Russia. Station No. 5549, water depth 56 m, strongly silted fine sand with detritus; No.56 cruise of the R / V “Professor Vodyanitsky” (15.12.2001) .

Description. The total length of the female body (Lt) 380‒400 μm ( Table 1; Fig. 1 A, D ; Fig. 2 A, H ). Body composed of 67‒70 annules, (annuli 3–6 μm wide). Cuticle along the entire length of the body transparent, with large numbers of setae of different length. The setae allocated strictly in transverse rows from the head to the base of the tail. Head short, rounded, narrower than the first annulus, bearing large, elliptical, thick-rimmed amphids, much broader than the head. About 80‒90 long and thin cephalic sensory setae anterior to amphids. Pharynx short, slightly expanding to the basis, without a bulb. A pair of salivary glands at its base ( Fig. 1 B, D ). A special elongated area at the very posterior edge of the esophagus, by the location of the salivary glands, which is the cardia (valve) that includes the beginning of the intestine. Eyes not observed (problematically). The body smoothly widening from the head to the middle and then gradually narrowing to the tail. Each annule of the body bearing a row of thin hair-like setae and spinous hairs, their length increasing from anterior towards the middle and the posterior parts of the body. Eight pairs of specific setae (15 μm) on a small basic cell without hairs along the body. These specific setae with diverse lengths and with a slightly thicker appearance than the rest of the setae. Reproductive system didelphic, amphidelphic with equally developed genital branches. Vulva located between annules 41 and 43 in holotype, 42 and 44 in paratype. Mature egg 30×32 μm. The tail composed of 6‒8 annules. The last ring (18‒19×23‒32 μm) of the tail large and smooth in the form of a triangle with a pointed end and rows of short setae, three long terminal tubes (13 μm) on the end of the tail.

Figures

Figure 1. Greeffiella sp.: A‒C ‒ specimen 1. А ‒ overall view, В ‒ head region, С ‒ tail region; D‒F – specimen 2. D ‒ head region, E – tail region, F ‒ overall view. Scale bars: А, F = 50 µm; В, C, D, E = 20 µm.

Figures 2. Greeffiella sp.: A‒G ‒ specimen 1. A ‒ overall view, B ‒ head region, C ‒ amphid, D – vulva, E – specific setae at the tail region, F ‒ specific setae in the middle part of the body; G – tail with terminal tubes; H‒L ‒ specimen 2, H – overall view of the specimen, I ‒ head, J ‒ tail with terminal tubes, K ‒ pharynx, salivary glands and cardia, L ‒ long hair-like and spike–like setae on tail part. Scale bars: A, H = 50 µm; B, D, I, J, K, L = 20 µm; C, E, F, G = 10 µm.