Achaeta etrusca Rota, 1995

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 : 1999-2001

Achaeta etrusca Rota, 1995

( Figure 4 )

Achaeta etrusca Rota, 1995, pp. 197–198 , figure 8A–C.

Achaeta etrusca, Rota et al. 2013 , table 1 and figure 3 (species ‘s5’); Rota et al. 2014, tables 1, 2 and Suppl. 1.

Material examined

Type material. MCZR Oligochaeta 0049–0050, Holotype and one paratype from Italy, Tuscany (Tu-3), Rovine di Castelvecchio (43.4320°N, 11.0052°E, 400 m asl), about 4 km Ν of Castel S. Gimignano, 8 km SW of San Gimignano (Siena). Oak wood on limestone, pH 7.1–7.3, 23.05.1994, E. Rota coll.

New material (in the author’ s collection). About 150 specimens from Italy, Campania (Ca-2), plots N1 – N3 , 13.05.2009 and 26.10.2009 . Nine specimens from Italy, Tuscany (Tu-4), 8– 16.06.2004 . Seven specimens from Italy, Tuscany (Tu-5), 24.04.2009 and 05.11.2009 .

Augmented diagnosis

Live body length 2.0– 3.5 mm, width 0.15–0.21 mm at XII. Segments 21–24. Paired knob-like cutaneous gland structures dorsolateral in II– VI ( Figure 4A ). Clitellum laterodorsally made of hyaline cells irregularly scattered among granular cells, with a narrow middorsal interruption (25 μm); ventrolaterally only granular cells occur; clitellum absent midventrally (gap as wide as the distance between male pores, 64 μm). Secondary pharyngeal glands in V and VI. Pronounced oesophageal loops in IV and VII, visible both in vivo ( Figure 4B, C ) and in fixed material. Dorsal blood vessel originating in VII and entering directly into VI, i.e. bypassing the oesophageal loop of VII. Three pairs of preclitellar nephridia (6/7–8/9). Sperm funnels 48–53 by 27–35 μm. Sperm heads about 15 μm long, tails 25 μm. Penial bulbs in XII, compact, oval, 32 μm long. One egg mature.

Remarks

The validity of this species has recently been questioned by Graefe (2007), and its synonymization with A. iberica has been proposed ( Schmelz and Collado 2010, 2012). The original description ( Rota 1995) mentioned ‘inconspicuous lens-shaped epithelial cells observed dorsolaterally from II’. These words have been misinterpreted as if referring to the lentiform gland cells segmentally punctuating the sides of the body of A. iberica at three distinct levels, but the structures of A. etrusca swell inwards, occur as one dorsolateral pair per segment and are limited to segments II–VI (in segment I, more dorsal and bilobed structures occur, probably of a different nature) ( Figure 4A ). Thus they would rather seem homologous to the ‘dorsolateral epidermal follicles slightly protruding into the body cavity’ characterizing segments I, III–VI in A. antefolliculata Dózsa-Farkas and Boros, 2005 . Differences between A. etrusca and the latter include the number of secondary pharyngeal glands (two vs. one pair) and the pairs of preclitellar nephridia (three vs. two).

Distribution

This species was discovered originally in oak woodland soil on limestone in central Tuscany. The present new records in the outskirts of Siena and in Capodimonte Park, Naples city, confirm its association to evergreen Mediterranean woodland and scrubland on neutral soils. In Capodimonte Park it appeared equally abundant in spring and autumn.

Figures

Figure 4. Achaeta etrusca Rota, 1995. (A) Cephalic region in a dorsolateral view. Arrows and arrowheads point to the body wall structures in I and II–IV, respectively; uppermost arrow and arrowhead indicate the corresponding protrusions on the right inner side of I and II. (B and C) Dorsal views of segments I–IV and VI–IX, respectively, showing the conspicuous loops of the oesophagus in IV and VII. All from live specimens, anterior to the left.