Five new species of Enchytraeidae (Annelida: Clitellata) from Mediterranean woodlands of Italy and reaffirmed validity of Achaeta etrusca, Fridericia bulbosa and F. miraflores
Author
Rota, Emilia
text
Journal of Natural History
2015
2015-02-28
49
33
1987
2020
journal article
21162
10.1080/00222933.2015.1009514
8c6c97a7-1c63-41ba-b75a-217ce1a3411d
1464-5262
3997986
Achaeta borbonica
sp. nov.
(
Figure 1
)
Achaeta
sp. 1,
Rota et al. 2013
, table 1 and figure 3 (species ‘s1’);
Rota et al. 2014
, tables 1, 2 and Suppl. 1.
Type material
Holotype
.
MCZR
Oligochaeta
0174, whole-mounted specimen, fully mature.
Type locality
Italy
,
Campania
(Ca-1),
Astroni State Nature Reserve
,
8.5 km
to the northwest of
Naples
, under the canopy of the oldest
Q. ilex
trees surviving in the crater (
40.8490°N
,
14.1499°E
,
50 m
asl
). Thick coarse litter on loose, organic-rich soil with volcanic ash and pumice, pH 5.8,
27.10.2009
,
E
.
Rota
coll.
Paratype
.
MCZR
Oligochaeta
0175, one whole-mounted specimen, fully mature, from type locality,
14.05.2009
.
Other material.
One whole-mounted specimen from
type
locality,
14.05.2009
, in the author’ s collection.
Etymology
Discovered within a former hunting preserve for the Bourbon royal family.
Diagnosis
Small species, with flask-shaped glands occurring dorsally from V, clitellum including two mid-dorsally contiguous hyaline bands, male pores in XI, preclitellar nephridia one pair at 7/8, spermathecae short, confined to V, opening ventrally.
Description
Small, filiform species (
Figure 1A
). Live body length
2.2–3.2 mm
, width
0.125
– 0.150
mm
at XII; after fixation, length 1.3–2.0 mm, width
0.10 mm
at clitellum. Segment number 20–22. Prostomium (
Figure 1A
) rounded both in frontal and lateral views, pointing forwards, one-fourth longer than peristomium (32 μm after fixation). Flask-shaped glands present dorsally from V (
Figure 1B
), conspicuous (30–35 μm long
in vivo
, about 25 μm in fixed material), absent ventrally. Knob-like glands and lentiform glands absent. Clitellum (
Figure 1A, G, H
) in XI–1/2XII, gland cells in 18 transverse rows, hyaline cells present only dorsolaterally, forming one longitudinal band per side, the two hyaline bands dorsally contiguous; granular cells covering all other sides of clitellum but absent in its middle along the midventral line.
Figure 1.
Achaeta borbonica
sp. nov.
(A) Anterior body half in a dorsal view. Note the intestinal loop in IX; (B) lateral view of segments IV–V, showing the right spermatheca; asterisks indicate the oesophageal dorsal ridge; (C) ventral view of segment V, revealing the closely spaced spermathecal pores; (D) sperm funnel in segment X; (E) lateral view of nephridium in segment VIII; (F) coelomic cavity of caudal segments (lateral view), showing the coarse granulation of the chloragogenous cells and the small size of coelomocytes as compared with the flask-shaped glands. (G and H) Lateral views of clitellum,
in vivo
(G) and after fixation (H). All except (H) from live specimens. In (A), (D) and (E) anterior to the top; in all others, anterior to the right.
Head pore at 0/1. Spermathecal pores ventral at 4/5. Male pores in XI (
Figure 1A, G, H
).
Cuticle and body wall thin. No thickened septa. Brain twice longer than broad (60 μm long when fixed), posteriorly rounded. Oesophageal outer ridge dorsal on III– V (
Figure 1B
). Pharyngeal glands, three pairs, all well developed and connected dorsally, secondary lobes absent (
Figure 1A
). One pair of preclitellar nephridia, anchored (but not constricted) by septum 7/8 (
Figure 1A, E
).
Coelomocytes smaller than flask-shaped glands, oval or drop-shaped, finely rugose and grained, pale (
Figure 1B, F
). Transition between oesophagus and intestine gradual. Gut constantly forming a loop in IX (
Figure 1A
). Intestinal floor of 1/2XV– XVII modified as an inner ridge of tall cells (ventral intestinal ridge). Chloragogenous cells
in vivo
filled with large (3 μm) opaque inclusions (
Figure 1B–F
), somewhat resembling the oil globules filling of
Enchytraeus
species, but rendering the sides of gut dark-brown in transmitted light. Dorsal blood vessel arising in VI.
Seminal vesicle absent. Sperm funnels (
Figure 1D
) twice longer than broad,
in vivo
60 by 30 μm, with distinct collar (7 μm high). Heads of spermatozoa about 10 μm long and vasa deferentia 4.5 μm thick
in vivo
. Penial bulbs small, oval, compact, 25 μm long
in vivo
, 21 μm after fixation (
Figure 1A, G, H
). One egg mature, conspicuous, generally stretching through two whole segments (
Figure 1A
). Spermathecae (
Figure 1B, C
) short, confined to V, club-shaped, thicker-walled in their distal half (ectal duct), totally about 50 μm long and 15 μm across (live). Sperm arranged as a straight bundle inside ampulla.
Remarks
This new species resembles
A. minima
Southern,
1907
in body size, dorsal occurrence of the flask-shaped glands and position and size of the spermathecae (
A. minima
and
A. borbonica
sp. nov.
are the only known
Achaeta
species possessing flask-shaped glands with spermathecae confined to V), but differs from it by the cephalic displacement of the genital organs, the size of the sperm funnels and the location of the first preclitellar nephridia. An identical cephalic displacement of the genital organs, combined with ventral spermathecal pores, dorsal flask-shaped glands and possession of one pair of preclitellar nephridia, as in the new species, is observed in the northern European
A. abulba
Graefe, 1989
and
A. bibulba
Graefe, 1989
. From the latter two, the new species appears different because: (1) the nephridia comprise an anteseptal part and occur preclitellarly at 7/8 rather than at 6/7; (2) compact penial bulbs are present; (3) the spermathecae are confined to V and lack any glandular formation at pore.
Distribution
Only recorded in the Astroni State Nature Reserve, sexually mature both in spring and autumn.