Fridericia bargaglii, Rota, 2015

Rota, Emilia, 2015, Five new species of Enchytraeidae (Annelida: Clitellata) from Mediterranean woodlands of Italy and reaffirmed validity of Achaeta etrusca, Fridericia bulbosa and F. miraflores, Journal of Natural History 49 (33), pp. 1987-2020 : 2001-2005

Fridericia bargaglii sp.nov.

( Figures 5–6 )

Fridericia polychaeta, Rota 1995, p. 215 (partim)

Fridericia sp. 3, Rota et al. 2013, tables 1 and figure 3 (species ‘s27’); Rota et al. 2014, tables 1, 2 and Suppl. 1.

Type material

Holotype. MCZR Oligochaeta 0179, whole-mounted specimen, fully mature .

Type locality

Italy, Tuscany (Tu-6), Siena city, Orti dei Tolomei (43.3146°N, 11.3324°E, 330 m asl), grass under Laurus nobilis shrubs on yellowish-brown sandy soil, 31.03.2004, E. Rota coll.

Paratypes. MCZR Oligochaeta 0180, one whole-mounted submature specimen, from Italy, Tuscany (Tu-8), 01.04.1992 . MCZR Oligochaeta 0181, one wholemounted specimen, submature, from Italy, Tuscany (Tu-5), 04.11.1993 . SMNH- Types 8723–8724, two whole-mounted specimens, submature, from type locality and date.

Other material. Several specimens, whole mounted or fluid preserved, from Italy, Tuscany, loc. Tu-3, Tu-5, Tu-6, Tu-7, Tu-8, Tu-9, Tu-10, in the author’ s collection.

Etymology

Named for Prof. Roberto Bargagli, for his dedication and achievements in environmental research, and with thankfulness for his enduring friendship and support.

Diagnosis

Large multisetose species (4÷7 – 6÷2: 4÷7 – 6÷2), clitellar gland cells in indefinite rows, ventrally reduced to a narrow strip behind male pores, extra lobes of pharyngeal glands ventrally in VII, nucleated coelomocytes large and pale, peptonephridia multi-branched at two distinct levels, five pairs of preclitellar nephridia, chylus cells in XIII–XV, dorsal blood vessel from XVIII–XX, large seminal vesicle, sperm funnels elongate conical, male slits I-shaped (longitudinal), subneural glands in XIII–XV, spermathecae large, elongate, with two toe-shaped aciliated diverticula and no distinct ectal gland.

Description

Colour white-yellowish, paler after storage in alcohol. Live body length 17–28 mm, width about 0.67–0.83 mm at XII; dimensions can be large also in fixed specimens: length 25 mm, width 0.55–0.60 mm at V, 0.8 mm at XII. Segment number 56–73, x = 63.5, s = 6.2 (n = 31). Prostomium 1.2 times longer than peristomium, frontally rounded, blunt conical in a lateral view, dorsally depressed in front of head pore, pointing forwards ( Figure 5A ). Epidermal sensory buds abundant on prostomium, segments I–II and pygidium. Epidermal glands small, dot-shaped, arranged in four complete transverse rows per trunk segment. Clitellum ( Figure 5B ) slightly elevated (30 μm), interrupted ventrally except immediately behind male openings in XII where a strip of both hyaline and granular cells occurs; both types of gland cells small, 12–18 by 8–12 μm, arranged in indefinite rows, the granular type twice as numerous as the hyaline type. Subneural glands on nerve cord midventral in IV ( Figure 5B ) and in XIII–XV, located either at the segment equator, or between the ventral chaetal bundles, or in the intersegment. Sometimes also a papilla midventral at 12/13.

Head pore at 0/1, oval (50 μm long). Dorsal pores from VII. Spermathecal pores in ‘lateral lines’ at 4/5, surrounded by glandular epidermis. Male pores as I-shaped longitudinal slits, with distinct, asymmetrical, transverse extensions.

Chaetae weakly hooked entally, 4÷7 – 6÷2: 4÷7 – 6÷2, but specimens with maximally six chaetae in preclitellar bundles are very frequent. Caudal bundles reducing to two or three chaetae only in last 10 segments. In fixed specimens, ectal tips of chaetae pointing posteriorly in anterior 25 segments, thereafter showing the opposite orientation. Length of chaetae maximal caudally, reaching 120–150 μm.

Cuticle thin, less than 2 μm thick throughout. Body wall thick but soft and relatively transparent. No thickened septa. Brain ( Figure 5A ) oval, with shallow anterior convexity, in vivo 190–204 by 135–146 μm. Peptonephridia ending in VI or VII, each consisting of a stout stem giving off many thin, long, equal-sized, straight branches at two distinct levels, proximally (or at midlength) and terminally (type c sensu Nielsen and Christensen, 1959) ( Figure 6D ). Pharyngeal glands four pairs, three of which partly merging dorsally at 4/5–6/7, plus extra lobes ventral in VII ( Figure 6A ). Five pairs of preclitellar nephridia (6/7–10/11), with efferent ducts arising antero- to midventrally from postseptal.

Coelomocytes: nucleated cells in vivo opaque when accumulated, filled with fine pale granules, up to 50–60 μm long, with very small nucleus; anucleate corpuscles small, 5–10 μm long. The worms discharge abundant coelomic fluid that coagulates at fixation. Chloragogen cells from V. Chylus cells in XIII–XV or XIII–1/2XVI. Ventral intestinal ridge not clearly visible. Dorsal vessel most frequently originating in XVIII–XX, with four pairs of thin lateral commissures: two starting from a common root in III, one in IV and one in V.

Seminal vesicle occupying 2–3 segments within X–XIII ( Figure 5C ), forming paired bulgings at both ends. Sperm funnels ( Figure 5C ) elongate conical, tapering toward vas deferens, each 600–900 μm long and 180–250 μm broad in its proximal one-third (which in vivo appears opaque). Collar distinctly set off, 7 μm high, slightly narrower or as wide as funnel. Heads of spermatozoa about 130 μm long. Vasa deferentia 11 μm thick in vivo. Each penial bulb 150–170 μm long (fixed). Up to two eggs mature.

Spermathecae ( Figure 6A–C ) independently communicating with the dorsal side of gut entally at 5/6; ampulla elongate with two stalked diverticula (resembling big toes) apically converging toward the ectal duct. Total width of ampulla and diverticula 204–235 μm. Each diverticulum 83–105 μm wide, ending with a large hemispherical (toe-nail shaped) sperm chamber ( Figure 6B, C ). Inner wall of ampulla pimpled throughout. Inner wall of diverticula not ciliated. Sperm mass not rotating inside the diverticula. Ectal duct 500–550 μm long (1.5–2 times the ampulla) and only 25–30 μm thick in vivo; duct canal straight, of uniform width (2.5 μm); duct projecting into ampulla as a broad bulb lined by tall cells. Some small, indistinct gland cells at spermathecal ectal pores.

Remarks

This species has been earlier ( Rota 1995) confounded under the name of F. polychaeta Bretscher augm. Southern (1907). After the improved characterization and recognition of the latter taxon as a new distinct species, F. healyae , by Schmelz (2003), and following personal observations on Swedish material of F. healyae (see Erséus et al. 2005), I was able to separate the Italian material compiled in Rota (1995) into specimens belonging to F. healyae (sample from site Tuscany 17) and specimens belonging to the present new species (all remaining Tuscan samples). In F. healyae the clitellum is girdle-shaped and the gland cells are arranged to form an irregular honeycomb tiling, with a ratio between hyaline and granular cells of 1:4 (pers. obs.). In F. bargaglii sp. nov. the two types of cells occur with a ratio of about 1:2 and the clitellum is nearly absent ventrally. Other important differences from F. healyae are the two-level branching of peptonephridia, the always welldeveloped seminal vesicle, the extra pair of pharyngeal glands in VII, the many subneural glands and the absence of inner ciliation in the spermathecal diverticula. F. bargaglii sp. nov. differs from F. polychaeta Bretscher, 1900 as originally defined (whether or not one accepts the latter as a valid taxon), by its brain shape, the number of pharyngeal glands, the origin of the dorsal vessel, and the habitat (unlike F. bargaglii sp. nov., both F. healyae and F. polychaeta appear to be associated with wet soils).

Distribution

Apparently endemic to Tuscany, associated with neutral soils. Recent studies ( Rota et al. 2013, 2014) have confirmed the abundance of this species in urban (Villa Patrizia, plots S2 and S3) and suburban (Belcaro) districts in Siena.

Figures

Figure 5. Fridericia bargaglii sp. nov. (A) Cephalic region (lateral view), showing the midventral glandular papilla in IV; (B) ventrolateral view of segments X–XV; the elliptical contour shows the continuity of the clitellum behind the male pores; arrows indicate the subneural glands in XIII–XV; (C) sagittal optical section through XI–XIII (lateral) in a preclitellate specimen, showing the male inner reproductive organs. All from permanent whole-mounted specimens, anterior to the right.

Figure 6. Fridericia bargaglii sp. nov. (A) Semi-schematic drawing of segments IV–VII in a live specimen (dorsal view), showing the spermathecae and the pharyngeal glands; (B and C) spermathecae from whole-mounted specimens (in (C) diverticula seen in a side view); (D) peptonephridia (free-hand sketches) in living specimens; (E) shape and reciprocal distance of the male openings (ventral view). In all, anterior to the top.