Seven new species and one new species record of Sabatieria (Nematoda: Comesomatidae) from the continental slope of New Zealand
Author
Leduc, Daniel
text
Zootaxa
2013
3693
1
1
35
journal article
10.11646/zootaxa.3693.1.1
6aab2b37-148a-4919-aafc-ea57260eeea8
1175-5326
284269
33A5FD00-282F-42D9-8A78-3FA9F33F86FB
Sabatieria exculta
sp. n.
(
Figs 11–12
,
Table 3
)
Material examined.
Holotype
male (NIWA 865995), collected
5 June 2007
, western Challenger Plateau (
532 m
water depth),
40.8814°S
,
170.8603°E
. Characteristics of surface sediment layer (
0–5 mm
): mostly silt/clay (67.6%), with fine sand (15.1%), and very fine sand (11.4%); calcium carbonate content: 56.0%; total organic matter content: 2.1 %; chloroplastic pigment concentration:
1344 ng
/gDW sediment. Two male and two female
paratypes
(NIWA 865996), same data as
holotype
.
Etymology.
The species name is derived from the latin
excultus
(= adorned, refined) and refers to the unusual ornamentation of the cuticle consisting of both punctations and annulations.
Description.
Male
Body slender, cylindrical, tapering slightly towards anterior extremity. Cuticle with transverse rows of dots, without lateral differentiation. Faint annulations (
i.e
., discontinuity running down entire thickness of cuticle) also present throughout body. Annulations result from fusion of every second or third transverse row of dots. Two dorso- and two ventro-lateral rows of short, sparse somatic setae, some associated with rounded hypodermal glands (
Fig. 12
A). Head slightly set-off by depression at level of
fovea amphidialis
. Six minute inner and outer labial papillae and four short cephalic setae. Anterior portion of buccal cavity small, cupshaped, posterior portion narrow.
Fovea amphidialis
spiral, 2.5 turns, located immediately posterior to cephalic setae. Marginal tubes not observed. Pharynx gradually widening towards posterior, not forming a true bulb. Nerve ring at about middle of pharynx length. Secretory-excretory system present, cellular body of ventral gland large, 19–20 µm by 25–28 µm, at level of intestine, pore situated 1.0 cbd posteriorly to nerve ring. Intestine wall with numerous small, colourless granules, with differentiation of rounded cells containing more densely packed granules in anterior portion.
Reproductive system diorchic with outstretched testes. Anterior testis on left of intestine, posterior testis on right of intestine. Mature sperm cells globular, 3 µm diameter by 4 µm long. Spicules paired, equal, arcuate, 1.3– 1.4 abd long, without capitulum, and with central cuticularised projection (lamella) extending from proximal end over one fifth of spicule length. Velum absent. Gubernaculum with pair of long, narrow, straight dorso-caudal apophyses, narrowest at base. Rectal gland surrounds gubernacular apophyses and distal portion of spicules. Ejaculatory glands not observed. Ten small tubular pre-cloacal supplements, one pre-cloacal seta. Tail conicocylindrical, with several short caudal setae and three short terminal setae. Three small caudal glands and spinneret present.
Female
Similar to male, but with slightly smaller
fovea amphidialis
and smaller ventral gland, 12–13 µm by 23–24 µm. Reproductive system didelphic, opposed, outstretched, with anterior branch to the left of intestine and posterior branch to the right of intestine. Spermatheca not observed. Vulva situated mid-body. Granular vaginal glands present,
pars proximalis vaginae
surrounded by constrictor muscle.
Diagnosis and relationships.
Sabatieria exculta
sp. n.
is characterised by a combination of having a slender body (
a
= 54–60), cuticle with lateral rows of punctations without lateral differentiation, and faint annulations resulting from fusion of every second or third lateral row of dots, short cephalic setae (3 µm),
fovea amphidialis
with 2.5 turns, large ventral gland, and long, narrow gubernacular apophyses.
Sabatieria exculta
sp. n.
belongs to the
praedatrix
group and can be differentiated from most other species of the genus based on the combination of slender body shape, short cephalic setae, and annulated cuticle without lateral differentiation of larger dots.
Sabatieria exculta
sp. n.
resembles
S. ancudiana
in body size and shape, cuticle without lateral differentiation, structure of
fovea amphidialis
, and size of gubernacular apophyses, but can be differentiated from the latter based on length of cephalic setae (3 µm in
S. exculta
sp. n.
vs
9 µm in
S. ancudiana
), number of pre-cloacal supplements (10
vs
16), and cuticle annulations (present
vs
absent in
S. ancudiana
).
S. exculta
sp. n.
also resembles
S. intermissa
and
S. triplex
in general body shape and structure of male copulatory apparatus, but differs in the length of cephalic setae (3
vs
>6 µm in
S. intermissa
and
S. triplex
), absence of lateral differentiation of the cuticle (
vs
present in
S. intermissa
and
S. triplex
), and number of pre-cloacal supplements (10
vs
>15).
Sabatieria exculta
sp. n.
also resembles
S. granifer
,
S. lawsi
, and
S. vasicola
in having short cephalic setae, but can be differentiated from the latter in the more slender body shape (
a
= 54–60
vs
26–40), absence of lateral differentiation of the cuticle (
vs
present in the other three species), and ratio of head diameter to posterior pharynx body diameter (0.43–0.46
vs
0.26–0.33).