Fridericia floriformis, Dozsa-Farkas, Klara, Felfoeldi, Tamas, Nagy, Hajnalka & Hong, Yong, 2019

Dozsa-Farkas, Klara, Felfoeldi, Tamas, Nagy, Hajnalka & Hong, Yong, 2019, Two new enchytraeid species from Jeju Island, Korea (Annelida, Clitellata), ZooKeys 824, pp. 87-108 : 93-97

Fridericia floriformis sp. n. Figs 1 E–G, 4, 5

Type locality.

Clayey soil, meadow (site 9), Yongnuni-orums, Gujwa-eup, Jeju Island, South Korea.

Holotype.

NIBRIV0000813661, slide No. 2437, adult, not stained, whole mounted specimen, collected on 26 Oct 2016 by Y. Hong.

Paratypes.

In total 18 adult stained and not stained specimens on slides and eight specimens in 70% ethanol, coll. Y. Hong. NIBRIV0000813662, slide No. 2293, DNA 1133, adult stained, whole mounted specimen from type locality. NIBRIV0000813663, slide No. 2427, from site 8 (clayey soil at the bottom of the dormant crater, meadow; 33.45859°N; 126.83192°E; 193 m asl.), 26 Oct 2016. P.121.1-P.121.14, slides No. 2291, 2314, 2332-2333, 2389, 2428-2432, 2436, 2438, 2440, 2481 from type locality. P.121.15-121.17, slides No. 2295, 2434, 2439 from site 8 (four specimens: slide 2434, 2436, 2438 and 2481 were not stained). P.121.18, five specimens in 70 % ethanol from type locality; and P.121.19, three specimens in 70 % ethanol from site 8.

Further material examined.

Four juvenile and five adult specimens only in vivo (one of the whole, adult specimens was processed with molecular analysis, DNA 1136). One additional specimen in vivo and for molecular analysis (DNA 1088) from Mt. Hallasan, Jeju Island (Gwaneumsa trail, 33.41667°N, 126.55000°E, 634 m asl., 26 Oct 2016, coll. Y. Hong), referred as ' Fridericia sp. 2' in Dózsa-Farkas et al. (2018).

Diagnosis.

The new species can be recognized by the following combination of characters: (1) large size (body length 14-20.5 mm in vivo), segments 48-65; (2) lateral chaetae often absent, maximum 2 per bundle, ventrally maximum 3-4 chaetae per bundle; (3) clitellum well developed, between bursal slits and before the male apparati only granulocytes; (4) body wall strong and cuticle thick (3-5 μm); (5) five preclitellar pairs of nephridia; (6) coelomo-mucocytes c-type occasionally with some refractile vesicles, lenticytes scarce and small; (7) dorsal vessel from XV–XVIII; (8) chylus cells in XII–XV, occupying 2-3 segments; (9) bursal slit longitudinal slightly bent, with small transverse extensions; (10) seminal vesicle not brown; (11) subneural glands absent; (12) sperm funnel approximately as long as half body diameter, collar narrower than funnel diameter, spermatozoa 400-580 μm long, heads 100-150 μm in vivo; (13) spermatheca with 9-12 sessile diverticula of varying size mostly without sperm in them, ectal duct long without ectal glands and ampulla entally openings separately into oesophagus.

Description.

Large, whitish, stiff worms. Holotype 15.3 mm long, 470 μm wide at VIII and 550 μm at the clitellum (fixed), 59 segments. Body length of the paratypes 14-20.5 mm, width 400-530 μm at VIII and 500-640 μm at the clitellum in vivo. Length of fixed specimens 8-17.3 mm, width 470-580 μm at VIII and 500-620 μm at the clitellum. Segments 48-65. Chaetal formula: 1,2,(0) - 2,0,1,2: 2,3,4 - (4),3,2,1. The inner chaetae being shorter and thinner than the outers: 30-35 × 2.5-3 μm and 54-63 × 5-6 μm (in preclitellar bundles). In the bundles with 2 chaetae the length of chaetae is different, in those with 3 chaetae one chaeta longer and the other two shorter. After the clitellum in lateral bundles of the middle part of body the chaetae mostly absent but at posterior body-end again occur 1 or 2 chaetae per bundle, length about 59-63 × 4.5-7 μm. Head pore at 0/I. Dorsal pores from VII; 2-3 transverse rows of hyaline epidermal gland cells per segment and in addition more transverse rows of dark yellow glands (visible only in vivo) (Fig. 4C). Clitellum in XII– 1/2XIII, well developed, girdle-shaped, hyalocytes and granulocytes arranged in indefinite rows or reticulate pattern (Fig. 4E, F), between bursal slits and before the male apparati only granulocytes (Fig. 4G). Body wall strong, thickness about 40-54 μm, cuticle thick about 3-5 μm in vivo and fixed (Fig. 4I, K), in forepart slightly stronger than at the body end.

Brain egg-shaped, about 140-180 μm long, about 1.5-2 times longer than wide in vivo (Fig. 4A) and 120-150 μm long and 1.4-1.7 times longer than wide in the fixed specimens (Fig. 4B). Oesophageal appendages long with many branches at the end in V (Fig. 4J). All pharyngeal glands with ventral lobes, those in 4/5 united dorsally, those in the 5/6 weakly united or unconnected dorsally and those in 6/7 unconnected dorsally but occasionally weakly united (Fig. 4L, M). All septa at 5/6-9/10 thickened. At anal region the radial gut dilator muscles well developed (Fig. 4N). Chloragocytes from V, 12-26 μm long in vivo. Dorsal vessel from XV–XVIII, (in one case in XIX), blood colourless. Midgut pars tumida in XXVI–XXXII occupying 4-7 segments (only in two specimens were visible). Five pairs of preclitellar nephridia from 6/7 to 10/11, length ratio anteseptale: postseptale 1: 2-2.5, adseptal origin of the efferent duct. Coelomo-mucocytes c-type, rounded or elliptic, sometimes with some refractile vesicles, length 28-44 μm in vivo (Figs 1F, 4H), in the fixed worms with granules and 15-28 μm long (Fig. 4I). Lenticytes scarce, small 4-7 μm long. Chylus cells in XII–XV, occupying 2-3 segments (Fig. 4D).

Seminal vesicle in XI, not brown. Sperm funnels cylindrical (Figs 1E, 5A), about 180-330 μm long and about 2 times longer than wide (in vivo). Funnel length in fixed specimens 100-220 μm, funnel body 1.2-1.8 times longer than wide (Fig. 5B); collar narrower than funnel body. The length of spermatozoa 400-580 μm, heads 100-150 μm in vivo (Fig. 5A), in fixed specimens spermatozoa 200-360 μm long and sperm heads 70-80 μm. Diameter of sperm ducts 9-10 μm in vivo, (7.5-8 μm, fixed). Male copulatory organs 130-170 μm long, 60-140 μm wide and 70-80 μm high, fixed (Figs 4G, 5 C–D), retractor muscles conspicuous (Fig. 5C). Bursal slits longitudinal, slightly bent, with small additional transverse extensions (Fig. 5E). Subneural glands absent. Spermathecae (Figs 1G, 5 F–J): no ectal gland, ectal ducts long, about 360-500 μm and 20-25 μm wide, canal 5-6 μm wide in vivo (250-500 μm long, 20-25 μm wide, canal 5 μm, fixed), not widened entally, projecting into ampulla, ental bulbs about 40-55 μm wide, fixed. Ampullae are surrounded distally by about 9-12 sessile diverticula of varying size: length 24-45 μm (fixed). Sperm in a circle in lumen of ampullar distal part. Diameter of ampulla and diverticula together 110-150 μm, mostly no sperm in the diverticula. Separate openings into oesophagus dorso-laterally. 1-4 mature eggs at a time.

Etymology.

Named after the shape of the spermathecal ampulla (more diverticula), which resembles a flower (flos, floris= flower, and formis = shaped as, Latin).

Molecular data.

Sequences deposited in GenBank: MH128729-MH128733 (ITS), MH124586-MH124589 (CO1), MH124597-MH124598 (H3).

Distribution.

In South Korea, at sites 8 and 9, Jeju Island, Yongnuni-orums, clayey soil, meadows.

Morphologically similar species.

There are only three species ( F. paraunisetosa Xie et al., 2000, F. ventrochaetosa Nagy, Dózsa-Farkas & Felföldi, 2018 and F. callosa Eisen, 1878) among all Fridericia species, which possess more diverticula of spermathecae and the lateral chaetal bundles absent or incomplete, varying with 0, 1 or maximum 2 chaetae. Fridericia paraunisetosa can easily be distinguished from F. floriformis sp. n. based on the following characters: smaller size (5.0-7.8 mm long vs. 8-17.3 mm, fixed), lateral chaetal bundles absent, ventrally only one chaeta per bundle (vs. 2-4 chaetae ventrally and 0-2 laterally), dorsal pores only from XVIII (vs. from VII), brain incised anteriorly (vs. convex), oesophageal appendages stout and unbranched (vs. with branches at the end) ( Xie et al. 2000). Fridericia ventrochaetosa could be distinguished from the new species by the total absence of the lateral chaetae and having spermathecal diverticula with stalk (vs. sessile) ( Nagy et al. 2018). The new species is similar to F. callosa in most traits (e.g., body size, segment number, strong body wall, thick cuticle, chaetal arrangement, number of preclitellar nephridia, position of chylus cells, the length of sperm), but the main differences between the two species are: in F. callosa the collar of sperm funnel not narrower than funnel body (Fig. 6A) (vs. narrower, Fig. 5A, B), seminal vesicle 2-3 segment large (vs. only in XI and not conspicuous). The spermathecae very variable in F. callosa (probably species complex) with or without diverticula, and the maximum number of diverticula is 6 ( Eisen 1878, 1879; Christensen and Dózsa-Farkas 1999; Schmelz 2003). From the material collected in Siberia in 1994, some stained slides were prepared now. On these slides, it was visible that the few diverticula are oriented towards the proximal ampullar part (Fig. 6 B–C) in contrast to the spermathecae of the new species, which always have many diverticula or diverticula-like protrusions surrounding the ampullae (Fig. 5 F–J).