Aphelenchoides spp. (Nematoda: Aphelenchida) and Panagrolaimus leperisini (Nematoda: Rhabditida) found associated with grass seeds in the Telperion Nature Reserve, South Africa
Author
Girgan, Chantelle
Author
Swart, Antoinette
Author
Marais, Mariette
Author
Fourie, Hendrika
text
Zootaxa
2018
2018-01-10
4370
2
137
155
journal article
31040
10.11646/zootaxa.4370.2.3
c8c77e57-832e-4a4a-8468-375d06593794
1175-5326
1143883
307E8947-81F4-4271-A02A-1115892BEC9C
Aphelenchoides rutgersi
Hooper & Myers, 1971
(
Fig. 3
&
4
)
Aphelenchoides rutgersi
was originally collected by W. Feder from around citrus roots Orlando,
Florida
,
U.S.
A and described from specimens cultured on
Setophoma terrestris
(H.N. Hansen) Gruyter, Aveskamp & Verkley or
Botrytis cinerea
Pers. (
Hooper & Myers 1971
)
. This species was then again found in the rhizosphere of tobacco plants in
Bulgaria
(
Katalan-Gateva & Budurova, 1976
).
Measurements.
See
Table 4
.
Description.
Female:
(n = 3) Habitus slightly curved ventrally. Cuticle finely annulated, annule width about 1 µm at mid-body. Lateral field 3–4 µm wide marked with three incisures (
Fig. 3D
). Head slightly offset (
Fig. 3A
). Lip region 2–4 µm high and 3–4 µm wide. Stylet 11–12 µm long with slight basal thickenings. Median bulb spherical with centrally located valve (
Fig. 3A
). Nerve ring situated 66–68 µm from anterior end, less than one corresponding body width from base of median bulb. Excretory pore 75–76 µm from anterior end, opposite nerve ring (
Fig. 3A
). Ovary outstretched with a single row of oocytes (
Fig. 3B
). Spermatheca elongate, containing sperm cells (
Fig. 4A
). Vulval lips slightly protruding with the vagina occupying about half the corresponding body width, curving anteriorly (
Fig. 3C
). Post-vulval uterine sac 37–43 µm in length, about 2.5 times vulval body width and shorter than half vulva-anus distance (
Fig. 3C
). Tail elongate conoid, 33–37 µm long. Terminus bearing a short, slightly ventrally-located mucro (
Fig. 3E–G
&
4B
).
Male:
Not found.
Discussion.
The female specimen of the
Aphelenchoides
sp. found associated with the seeds of
Aristida canescens
collected from the Telperion Nature Reserve were identified as
A. rutgersi
based on tail shape and morphological characteristics matching those of
Hooper & Myers (1971)
. There were only the following differences: Spermatheca and sperm cells observed in South African specimen. In the original description, spermatheca were indistinct and contained no sperm cells. However, males are present in this species and the presence of sperm cells is possible. This species is reported for the first time in
South Africa
and to our knowledge, it is the second report since its description. Specimens were deposited in the NCN under accession number 50541.
Relationships.
The
Aphelenchoides
specimens from
Aristida cansescens
were compared with species that are morphologically similar to the South African specimens in having a tail with one or two terminal mucronate structures and three incisures in the lateral field. Comparing the morphological and morphometric data of our Telperion specimens to those in Shahina’s (1996) compendium, the following species with a relatively long postvulval uterine sac (PUS) can be differentiated from
A. rutgersi
(PUS less than half the vulva-anus distance):
A. agarici
Seth & Sharma, 1986
,
A. minoris
Ebsary, 1991
, and
A. myceliophagus
Seth & Sharma, 1986
all have a PUS more than half the vulva-anus distance.
Some of the smaller species also differ based on shorter body length (542–582 µm in
A. rutgersi
):
A. breviuterallis
Eroshenko, 1968
(L = 410–460 µm) also has a shorter stylet (8 µm compared to 11–12 µm in
A. rutgersi
);
A. cibolensis
Riffle, 1970
(L = 360–460 µm) with a shorter tail (27 µm compared to 33-37 µm in
A. rutgersi
); while
A. trivialis
Franklin & Siddiqi, 1963
(L = 360–490 µm) has a reflexed ovary compared to no flexure in
A. rutgersi
.
A. curiolis
Gritsenko, 1971
has a significantly shorter stylet (6 µm compared to 11–12 µm in
A. rutgersi
).
A. chamelocephalus
(
Steiner, 1926
)
Filipjev, 1934
differs in the more posterior position of the vulva: 75–80% compared to 69–70% in
A. rutgersi
.
The species most morphologically similar is
A. swarupi
Seth & Sharma, 1986
and differs only in having a higher
c’
value (5 compared to
3–4 in
A. rutgersi
). Other closely related species based on morphology are
A. eltayebi
Zeidan & Geraert, 1991
and
A. sacchari
Hooper, 1958
.
Aphelenchoides eltayebi
differs in having a more offset head and a more anterior excretory pore (44µm from anterior vs. 76µm in
A. rutgersi
).
Aphelenchoides sacchari
differs in having oocytes arranged in two rows at the anterior end of the ovary (only one row in
A. rutgersi
).