New records of helminths of Sceloporuspyrocephalus Cope (Squamata, Phrynosomatidae) from Guerrero and Michoacan, Mexico, with the description of a new species of Thubunaea Seurat, 1914 (Nematoda, Physalopteridae)AuthorOca, Edgar Uriel Garduno-Montes deAuthorLopez-Caballero, Jorge D.AuthorMata-Lopez, RosariotextZooKeys20177164362http://dx.doi.org/10.3897/zookeys.716.13724journal articlehttp://dx.doi.org/10.3897/zookeys.716.137241313-2970-716-43C4763F6310DD493889D26A45E9E5819EC4763F6310DD493889D26A45E9E5819EThubunaea leonregagnonaesp. n.
Figs 1
A-H
; 2
A-FType host.Sceloporus pyrocephalus
Cope (
Squamata
:
Phrynosomatidae
).
Symbiotype.MZFC-HE 18345Type locality.
Los Pocitos, La Huacana,
Michoacan
, Mexico (
18°40'24.2"N
,
101°59'42.5"W
). Collected on July 7, 2005.
Site in host.Stomach.Prevalence and intensity of infection.23% (14 of 61 hosts examined), with a mean intensity of 11 (7-67).Type specimens.Holotype: CNHE 9426 (1 male); allotype: CNHE 9427 (1 female); paratypes CNHE 9428, 9429, 9430 and 9431 (9 females and 7 males).Etymology.
This species is named in honour of Virginia
Leon-Regagnon
(Instituto de
Biologia
, UNAM), who was the mentor of the authors of this paper, and for her valuable contribution to our knowledge of helminth parasites in Mexico.
General description.
Medium-sized nematodes, filiform body, cuticle with fine transverse striations along entire body. Males smaller than females. Round cephal
ic
plate in both sexes (Figs 1B, 2B). Deirids symmetrical, simple with rounded tip (Fig. 2A, C), located immediately posterior to nerve ring. Mouth with two round and simple lateral lips, each with three small teeth on its internal surface; each lip bears a lateral amphid, and a pair of sub-median papillae (Figs 1B, 2B). Pharynx short, cylindrical, opening into oesophagus. Oesophagus divided into anterior muscular portion and posterior glandular portion. Excretory pore in anterior region of body, posterior to nerve ring and located at level of division of muscular and glandular oesophagus. Posterior end conical and rounded in both sexes (Figs 1F, H, 2D, F).
Figure 1.
Thubunaea leonregagnonae
sp. n. A Anterior end, female, lateral view B Apical view, female C Anterior end, female, lateral view showing excretory pore and vulva D Embryonated egg, lateral view E Larvated egg, lateral view F Caudal end, male, ventral view G Caudal end, male, lateral view, caudal papillae and ornamentation not shown H Caudal end, female, lateral view. Scale bars: A 90
µm
; B 20
µm
; C 370
µm
; D 25
µm
; E 30µm; F 250
µm
; G 50
µm
; H 370
µm
.
Description of male (based on eight specimens; the number of measurements, where different from eight, is given in parentheses): Total body length (MTBL) 4.85-8.03 mm (6.19), width at mid-body 200-300 (243). Deirids 150-185 (166; n = 7) from anterior end. Nerve ring and excretory pore 100-168 (125) and 125-295 (179, n = 6) from anterior end, respectively. Pharynx length 23-45 (33). Oesophagus total length 613-1038 (800, n = 7), muscular portion length 108-170 (128, n = 7), glandular portion length 488-913 (671, n = 7). Ratio oesophagus total length: MTBL 0.1-0.16 (0.13, n = 7). Testis elongated, distributed in zigzag from anterior intestinal portion to posterior region, near cloaca. Caudal alae well developed, bearing ventrally numerous papilliform plates. Cloaca surrounded by numerous papillae (24-28), 11-14 sessile papillae and 10-16 pedunculate papillae distributed asymmetrically in the following arrangement: ventrolateral: 4-8 pedunculate on right, 6-9 pedunculate on left side; ventral, sessile: 5-8 on right and 4-8 on left side (Figs 1F, 2E, F). Number and disposition of papillae variable with respect to cloaca, thus, precloacal, paracloacal, and postcloacal positions not established. Spicules and gubernaculum absent. Tail 50-67 (59, n = 6) long.Description of female (based on ten gravid specimens; the number of measurements, where different from ten, is given in parentheses): Total body length (FTBL) 8.72-21.46 mm (14.61), width at mid-body 270-440 (349). Deirids 125-250 (173, n = 8) from anterior end. Nerve ring and excretory pore 100-188 (147, n = 8) and 193-343 (256, n = 6) from anterior end, respectively. Pharynx length 30-58 (41, n = 9). Oesophagus total length 853-1500 (1227, n = 7); muscular portion length 125-325 (220, n = 8), glandular portion length 703-1220 (996, n = 7); ratio oesophagus total length:FTBL 0.1-0.16 (0.14, n = 7). Didelphic, opisthodelphic, ovaries distributed in posterior region of body, uteri extended parallel along almost entire body. Vagina muscular, directed posteriorly, located in anterior region of body close to anterior end of intestine, vulva at 1130-2570 (1770) from anterior end (Fig. 1C). Ratio distance vulva to anterior end of body: FTBL 0.11-0.13 (0.12). Tail 25-30 (27, n = 8) long. Embryonated eggs occupying almost entire uterus, thick shelled with smooth surface, 39-44 (41, n = 15) long by 29-33 (31, n = 15) wide (Fig. 1D); larvated eggs located near vulva, 45-50 (48, n = 15) long by 38-40 (39, n = 15) wide (Fig. 1E).Remarks.
The family
Physalopteridae
is composed of three subfamilies:
Thubunaeinae
Sobolev, 1949,
Proleptinae
Schulz, 1927 and
Physalopterinae
Railliet, 1893 (
Chabaud 1975
).
Thubunaeinae
comprises two genera
Thubunaea
and
Physalopteroides
Wu & Liu, 1940, both of which are parasites of reptiles and are characterized by the absence of a cephalic ring, the presence of numerous caudal papillae, and an ornamented
cuticle
forming papillary plates distributed on the surface of the cauda in males (
Chabaud 1975
). These two genera differ from each other mainly by the symmetry of their cephalic structures; in
Thubunaea
these structures are symmetrical, while they are asymmetrical in
Physalopteroides
(
Chabaud 1975
). Some authors, for example
Moravec et al. (1997)
, considered that the morphological features of
Thubunaea
and
Physalopteroides
have rarely been analysed using techniques such as SEM, and that these observations could provide detailed information to assess the validity of these two genera. However, to the best of our knowledge, SEM studies are still scarce in both genera, being available for only three species of
Thubunaea
(
Moravec et al. 1997
,
Pazoki and Rahimian 2014
,
Ramallo et al. 2016
) and two species for
Physalopteroides
(
Elwasila 1990
,
Goswami et al. 2016
). The specimens described in the present study show a symmetrical cephalic structure, as in
Thubunaea
.
Currently, 20 species of
Thubunaea
are considered as valid: one in the Afrotropical region,
T. fitzsimonsi
Ortlepp, 1931; five in the Nearctic region,
T. cnemidophorus
Babero & Matthias, 1967,
T. ctenosauri
Moravec, Salgado-Maldonado &
Mayen-Pena
, 1997,
T. iguanae
Telford, 1965,
T. intestinalis
Bursey & Goldberg, 1991 and
T. leiolopismae
Harwood, 1932; two in the Neotropics,
T. parkeri
Baylis, 1926, and
T. eleodori
Ramallo, Goldberg, Bursey, Castillo & Acosta, 2016; six in the Oriental region,
T. aurangabadensis
Deshmukh, 1969,
T. brooki
Deshmukh, 1969,
T. hemidactylae
Oshmarin & Demshin, 1972,
T. mirzai
Narayan, 1941,
T. singhi
Deshmukh, 1969, and
T. syedi
Deshmukh, 1969; two in the Palearctic region,
T. schukurovi
Annaev, 1973 and
T. smogorzhewskii
Sharpilo, 1966; and four species in the Saharo-Arabian region,
T. baylisi
Akhtar, 1939,
T. dessetae
Barus & Tenora, 1976,
T. mobedii
Pazoki & Rahimian, 2014 and
T. pudica
Chabaud & Golvan, 1957 (
Ramallo et al. 2016
).
Six of these species lack spicules, as is the case in
T. leonregagnonae
sp. n.:
T. cnemidophorus
,
T. eleodori
,
T. fitzsimonsi
,
T. mobedii
,
T. parkeri
and
T. schukurovi
(Table 3). Males of four of these species (
T. eleodori
,
T. fitzsimonsi
,
T. parkeri
and
T. mobedii
) are larger in body length than
T. leonregagnonae
sp. n. (10.25-11.16, 8.5-9, 10.5, 11.4-15.4 vs 4.85-8.03 mm, respectively). In the number of papillae, pedunculate or sessile, the new species also differs from most of these six species.
Thubunaea leonregagnonae
sp. n. has 10-16 pedunculate papillae and 11-14 sessile papillae,
T. mobedii
does not have pedunculate papillae; in contrast,
T. fitzsimonsi
and
T. parkeri
lack sessile papillae, and in this latter species the number of caudal papillae is smaller (16-20) than in the present specimens (24-28) (Table 3).
Thubunaea leonregagnonae
sp. n. is most similar to
T. cnemidophorus
,
T. eleodori
and
T. schukurovi
, however, it can be distinguished from the last two species in the number of sessile papillae:
T. eleodori
has ten and
T. schukurovi
has 16, instead of 11-14 in
T. leonregagnonae
sp. n. Males of
T. leonregagnonae
sp. n. and
T. cnemidophorus
can be differentiated mainly by having a different oesophagus length/MTBL ratio (0.1-0.16 vs 0.26) and by the former having a smaller body width (200-300 vs 350-390).
Figure 2.
Thubunaea leonregagnonae
sp. n. Scanning electron micrographs. A Anterior end, male, lateral view showing deirid (D) B Apical view, female, showing sub-median papillae (P) and amphids (A) C Deirid, lateral view D Posterior end, female, ventrolateral view E Posterior end, male, ventral view F Caudal end, male, ventral view. Scale bars: A 50
µm
; B 10
µm
; C 2.5
µm
; D 50
µm
; E 100
µm
; F 50
µm
.
Table 3. Morphological characters of
Thubunaea
spp. lacking spicules in males. Measurements in micrometres, unless otherwise indicated.