Fridericia ventrochaetosa Nagy & Felföldi & Dózsa-Farkas 2018, sp. n.
| Main Authors: | Nagy, Hajnalka, Felföldi, Tamás, Dózsa-Farkas, Klára |
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| Format: | info publication-taxonomictreatment Journal |
| Terbitan: |
, 2018
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/5951820 |
Daftar Isi:
- Fridericia ventrochaetosa sp. n. (Figures 1–3) Fridericia sp. Dózsa-Farkas & Felföldi 2017: 52 – 53, 2018: 4 – 5. Holotype. F. 29, slide No. 2267, adult, unstained, whole-mounted specimen. Type locality. Kȏszeg Mts. (Hungary), Steirer Houses, mesophile montane hay meadow, 47o22.201N, 16o28.045E, 667 m asl, leg. K. Dózsa-Farkas, J. Farkas, M. Pobozsny, 24.10.2016. Paratypes (in total 14 specimens). P.112.1.1–112.1.4, slides No. 2218, 2219 (DNS 978), 2225, 2226, four adult, stained specimens from Rax Mts., mixed forest (Picea abies, Betula pendula), 47o40.538N, 15o43.140E, 1116 m asl, leg. J. Farkas, 13.05.2016. P.112.2.1–112.2.7, slides No. 2266a–c– 2268–2269 (DNS 1102), 2273– 2274, 2345 (DNS 1116), 2346, 7 adult specimens, stained (except P.112.2.4 No. 2273), whole-mounted specimens from the type locality, leg. K. Dózsa-Farkas, J. Farkas, M. Pobozsny, 24.10.2016. P.112.3, one specimen in 70% ethanol (body end was processed for molecular analysis, DNS 1114). Further material examined. Four juvenile and two adult specimens in vivo (the whole adult specimens were processed for molecular analysis, DNA 1009, 1115). Etymology. Named after the chaetae, which are present only in the ventro-lateral chaetal bundles. Diagnosis. The new species can be recognized by the following combination of characters: (1) large size (body length 15–24 mm in vivo), segments (43) 48–60; (2) lateral chaetae absent, ventral maximum 3–4 chaetae per bundle; (3) clitellum widely interrupted dorsally and the hyalocytes and granulocytes arranged in dense rows laterally and after the bursal opening; (4) body wall strong and cuticle thick (8–14 μm); (5) five preclitellar pairs of nephridia; (6) coelomo-mucocytes b-type, lenticytes large, 8–12 μm long; (7) blood light pink; (8) chylus cells in XII–XV, occupying 2–3 segments; (9) bursal slit longitudinal with transverse extensions; (10) seminal vesicle large; (11) subneural glands absent; (12) sperm funnel approximately as long as body diameter or somewhat longer, collar narrower than funnel diameter, spermatozoa long, difficult to measure, sperm heads 150–250 μm long (in vivo); (13) spermatheca with 4–6 stalked diverticula, long ectal duct without ectal glands and separate entally. Description. Large, whitish, stiff worms. Holotype 23.3 mm long, 530 μm wide at VIII and 630 μm at the clitellum (in vivo). The fixed worm 19.0 mm long, 700 μm wide at VIII and 750 μm at the clitellum, 56 segments. Body length of the paratypes 15–24 mm, width 500–620 μm at VIII and 600–730 μm at the clitellum (in vivo). Length of fixed specimens 11.5–18.5 mm, width 520–700 μm at VIII and 600–770 μm at the clitellum. Segments (42), 48–60. Chaetae only in ventro-lateral bundles, except in one specimen (P. 112.2.5. slide No. 2273), here 1 chaeta in 1 lateral bundle of IV. Chaetal formula: 0 – 0: 1,2,3,(4) – (3),2,1,0,1. Inner chaetae shorter and thinner than outer: 58– 70 x 5–6 μm against 70– 80 x 9 μm and 34– 42 x 4 μm (in preclitellar bundles). Behind clitellum the two chaetae in a bundle of different size, at body end often only 1 chaeta per bundle, size about 90–110 x 10–12 μm. Head pore at 0/I. Dorsal pores from VII. Epidermal gland cells 5–6 transverse rows per segments (Fig. 1C). Epidermis glandular around spermathecal pore (Fig. 3G). Clitellum in XII–1 /2XIII. Glands dorsally absent, gap about 200–400 μm wide (Fig. 1I), ventrally absent between and anterior to male apparatus, but present posteriorly (Fig. 2B), hyalocytes larger than granulocytes, arranged in dense transverse rows (Fig. 1H). Body wall strong, thickness about 40–70 μm, cuticle thick, about 8–14 μm in vivo and fixed (Fig. 1D), (in forepart slightly stronger than at the body end). Brain egg-shaped, about 200–240 μm long, about two times longer than wide in vivo (Fig. 1A) and 170–203 μm long and 1.4–1.8 times longer than wide in the fixed specimens (Fig. 1B). Oesophageal appendages long with numerous, elongate branches at the end in V–VI (Fig. 2A). All pharyngeal glands with ventral lobes, those in 4/5 mostly united dorsally, those in 5/6 and 6/7 weakly united dorsally, occasionally all three pairs unconnected dorsally. Septa of V–X thickened (Fig. 1E). Chloragocytes from V, 15–25 μm long (fixed specimens). Dorsal vessel from XX–XXIII, blood light pink. Midgut pars tumida in XXX–XXXVIII occupying 5– 7 segments (Fig. 2C). Five pairs of preclitellar nephridia from 6/7 to 10/11, length ratio anteseptale: postseptale 1: 1.5–2, adseptal origin of the long efferent duct. The nephrostome not embedded in the anterior part, oriented horizontally (infrequent in Fridericia species) (Figs. 1L–M). Coelomo-mucocytes b-type, i.e. with refractile vesicles at cell periphery, length 34–53 μm in vivo (Fig. 1J), 20–35 μm in the fixed worms (Fig. 1K). Lenticytes scarce, large, 8–12 μm long. Chylus cells in XII–XV, occupying 2–3 segments (Fig. 2D). Seminal vesicle in IX–X or XI–XII. Sperm funnels cylindrical, mostly tapering distad (Fig. 2I), about 600–860 μm long and 2.4–3 times longer than wide (in one specimen 4 times longer than wide) (in vivo). Funnel length in fixed specimens 350–550 μm, funnel 1.5–2.5 times longer than wide (Figs. 2J, 3A); collar narrower than funnel body. The entire length of spermatozoa is difficult to measure in vivo, heads 150–250 μm, in fixed specimens spermatozoa 350–700 μm long and sperm heads 150–230 μm. Diameter of sperm ducts 9–10 μm (fixed). Male copulatory organs large, 260–350 μm long, 130–160 μm wide and 110–125 μm high (fixed), bursa large (Figs. 2B,E,H). Bursal slits longitudinal with additional transverse extensions (Figs. 2F–G). Subneural glands absent. Spermathecae (Figs. 3B–F) similar to the spermathecae of F. galba (Figs. 5D–E): no ectal gland, ectal ducts very long, about 650–840 μm and 32–35 μm wide, canal about 8 μm wide in vivo (520–640 μm long, 25–30 μm wide, canal 5 μm, fixed), not widening entally, projecting into ampulla, ental bulbs wide, about 70–90 μm. Ampullae surrounded distally by 4–6 stalked diverticula of various size: diameter of diverticula 45–90 μm, stalks about as wide and long as diverticula, with ciliated subchamber, ampullae 100–130 μm wide and not considerably set off from distal part, separate openings into oesophagus. 1–3 mature egg at a time. Distribution and habitat. In Kȏszeg Mts., in mesophile montane hay meadow, and in Rax Mts., in a mixed forest (Picea abies, Betula pendula). Differential diagnosis. There are only two species of Fridericia, F. paraunisetosa Xie et al. 2000 from NE China and the new species, with multiple spermathecal diverticula plus laterally completely absent chaetae. F. paraunisetosa can easily be distinguished from F. ventrochaetosa sp. n. based on the following characters: smaller size (5.0– 7.8 mm vs. 11.5–18.5 mm, fixed), in ventral bundles only one chaeta per bundle (vs. 2–4), dorsal pores only from XVIII (vs. from VII), brain incised anteriorly (vs. concave), oesophageal appendages stout and unbranched (vs. many branches) and spermatheca with sessile diverticula (vs. with stalk) (Xie et al. 2000). Apart from the absence of the lateral chaetae, the new species is highly similar morphologically to Fridericia galba. To compare the two species, we studied specimens of F. galba sampled from the same two mountains where the new species occurred, and some additional specimens from other sites in Hungary. All these specimens of F. galba had spermathecae with more than 5 spermathecal diverticula. The comparison of the most important traits of the two species is given in Table 1. Table 1 shows that the two species are broadly the same in size, number of segments, oesophageal appendages, origin of dorsal vessel, sperm funnel (comp. Figs. 2I –J, 3A with Fig. 5C), the male apparatus (comp. Figs. 2E,H with Fig. 4J). Spermathecae are also almost the same: ectal duct very long, no ectal gland, more than 2 diverticula with stalks (comp. Figs. 3B–F with 5D–E). The number of diverticula is mostly the same (6), but it varies in the new species between 4 and 6 and in the individuals of F. galba studied by us, between 5–9. The shape of the diverticula and the subchamber and ampullae are almost the same, only the stalks are slightly shorter (Table 1). However, differences can also be observed. The main differences are the absence of the lateral chaetae and the lower number of ventral chaetae in the bundles in the case of the new species (maximum of 3–4; in F. galba 4–7, Fig. 4E). Furthermore, both species have thick body wall but the cuticle in F. ventrochaetosa sp. n. is much thicker (8–14 μm; in F. galba 1–1.5 μm) (Table 1, Figs. 1D vs. Fig. 4D). Epidermal glands are well-visible, but in F. galba often occur conspicuous brown glands, too (Fig. 4C, E). The mucocytes are about the same length and the matrix may be filled with refractile vesicles in F. galba, but this granulation in the new species is much more prominent (Fig. 1J) and the lenticytes are also larger (Table 1). Further differences: chylus cells and midgut pars tumida are further back in F. galba, and the blood is light pink in F. ventrochaetosa sp. n. but colorless in F. galba (Table 1), and the epithelium of the prostomium of the new species is thicker, more conspicuous (Fig. 1F–G), than in F. galba (Fig. 4F). Last, but not least, individuals of F. galba often have large accessory sexual glands, mostly only one side in V, XI, XIII (Figs. 4H–J), but these organs are absent in the new species (Table 1). After surveying references describing F. galba previously (for complete bibliography see Schmelz 2003), it could be stated that the features of specimens studied by us fall within the range of variation reported earlier. However, since we provided more morphological characters and measurement data (Table 1), a more detailed comparison was possible with the new species. It should be noted that in some descriptions, few traits of F. galba are more variable as in the case of our specimens; e.g. segment number 40–45, length 15–20 mm in Vejdovský (1879), (48)–64–71–(81) and 20–40 mm in Nielsen & Christensen (1959), 55–61 segments and 18– 21 mm in Rota (1994) or 60–70 segments and 15–25 mm length in Schmelz (2003), respectively. Difference could be found in the number of spermathecal diverticula; e.g. Vejdovský (1879) reported 3–5, Nielsen & Christensen (1959), Schmelz (2003), and Schmelz and Collado (2010) reported 2–8. In the case of other characters we recorded generally the same as in previous references, although most of the previous descriptions lack measured values. Other authors including us conceive that the presence of accessory sexual glands is a characteristic feature of this species, even if it is absent in some specimens. Despite the above-mentioned variation of morphological characters, the new species could be easily distinguished from F. galba.
- Published as part of Nagy, Hajnalka, Felföldi, Tamás & Dózsa-Farkas, Klára, 2018, Morphological and molecular distinction of two Fridericia species (Clitellata, Enchytraeidae) having same spermatheca type, pp. 111-123 in Zootaxa 4496 (1) on pages 112-117, DOI: 10.11646/zootaxa.4496.1.8, http://zenodo.org/record/1447053