Measurements: Length=1400 micrometers (um) (1200-1600), width=128 um (110-144), stoma length=2.7 um (2.1-3.2), stoma width=8.4 um (7.9-8.7), anterior end to excretory pore=81 um (73-99), to nerve ring=105 um (95-122), esophagus length=153 um (139-178), Tail=39m um (36-44), width at anus=45 um (39-50), mucron length=1.8 um (0-4.9),spicule length=49 um (42-53), spicule width=12.4 um (10.6-14.6), gubernaculum length=33 um (29-37), gubernaculum width=7.2 um (6.6-8.0), D%=53, SW%=110, GS%=68.
Male, second generation: Second generation males similar to those of the first generation but smaller.
Female, first generation: Body elongate, moderately curved when heatkilled or fixed in 4% formalin or TAF. Cuticle smooth, slightly annulated when observed with SEM. Head bluntly rounded, slightly tapering anteriorly. Tail of mature female obtuse short, with postanal swelling. In young female, tail longer with a finger-like tip. Vulva a transverse slit, strongly protruding from the body surface, asymmetrical, and situated at midbody. Oral opening surrounded by inconspicuous lips, 6 labial papillae, and 4 cephalic papillae. Amphids distinct, located laterally between labial and cephalic circle. Stoma short, shallow. Cheilorhabdions prominent, sclerotized. Posterior to cheilorhabdions, another smaller sclerotized structure, prorhadions. Esophagus muscular with cylindrical corpus, slightly swollen metacorpus, distinct isthmus, and well-developed basal bulb containing a valve. Nerve ring surrounding isthmus. Excretory pore located posteriorly to nerve ring, often at the midle of basal bulb. Gonads amphidelphic with reflexed ovaries. Vagina short leading into paired uteri. Females oviparous, but eggs later hatch inside their body and form endotokia matricidia. Rectum narrow, anal opening distinct.
Female, second generation: Second generation female similar to first generation females but smaller. Tail tip pointed, but not mucronated, tail longer than anal body width. Excretory pore located more anteriorly than in the first generation, close to nerve ring. Pygmy forms observed.
Infective juveniles: Body narrow, elongate, often enclosed in second stage cuticle, sometimes the cuticle is lost. Mouth and anus closed. Labial papillae not developed, cephalic papillae and amphids distinct. Cuticle smooth, slightly annulated. Lateral fields composed of 8 ridges . Alimentary tract collapsed. Excretory pore slightly anterior to nerve ring. Tail pointed, but not as attenuated as in most of earlier described species. Minute phasmid observed from the dorsoventral view.
Measurements: Length=950 um (797-1101), width=33 um (30-36), anterior end to excretory pore=63 um (56-66), to nerve ring=105 um (99-111), esophagus length=134 um (119-145), tail=79 um (69-86), Width at anus=20 um (19-22), a=28.8, b=7.1, c=12.1, D%=47, E%=80.
Type Specimens
Holotype (male), allotype (female) deposited in the collection of the
Department of Insect Pathology, Institute of Entomology, Czech Academy
of Sciences, Ceske Budejovice. Paratypes at the same place and at the Laboratoire
de Pathologie Comparee, Universite Mont- pellier, France.
Diagnosis and relationships:
S. cubanum can be separated from all species, excluding S.
glaseri and S. anomalae, of the family Steinernematidae by the
average length of infective juveniles (1283 um). Infectives of other described
species are, on average, distinctly shorter than 1000 um. The eight ridges
in the lateral field of infectives differentiate S. cubanum from
S.
affine and S. intermedium which have seven or six ridges, respectively.
Male tail of S. cubanum without a mucron that is typical for S.
kraussei, S. feltiae, S. alfine, S. carpocapsae, S. rarum, S. kushidai,
second generation, S. scapterisci, and for the first generation
of S. neocurtillae. S. cubanum is differentiated from the
related species S. glaseri and S. anomalae by the following
characteristics: the second generation female tail is pointed but without
mucron-like projection which is typical for S. glaseri. Position
of the excretory pore of adults of the first and partly of the second generation
is more posterior to nerve ring than in S. glaseri. Spicules and gubernaculum
are shorter than in S. glaseri, and the gubernaculum is shorter
than in S. anomalae. Spicule tip is not hook-like as in S. glaseri.
Tail of adults of S. anomalae is much longer than in S. cubanum.
S.
cubanum differs from infectives of both S. glaseri and S.
anomalae in having a longer distance from head to excretory pore and
a shorter tail corresponding with the higher value of ratios D and E. Finally,
there were no positive cross hybridizations between S. cubanum with
S. glaseri, S. anomalae,and S. kraussei.
LITERATURE CITED
Mracek, Z., E. A. Hernandez, and N. E. Boemare. 1994. Steinernema cubana sp. n. (Nematoda: Rhabditida: Steinernematidae) and the preliminary characterization of its associated bacterium. Journal of Invertebrate Pathology 64:123-129.
This document was constructed and is maintained by KHUONG
B. NGUYEN
Entomology & Nematology Department
University of Florida