Paratrichodorus benalupensis, Decraemer & Archidona-Yuste & Clavero-Camacho & Vovlas & Cantalapiedra-Navarrete & Alba & Ruiz-Cuenca & Castillo & Juan & Palomares-Rius, 2024

Decraemer, Wilfrida, Archidona-Yuste, Antonio, Clavero-Camacho, Ilenia, Vovlas, Alessio, Cantalapiedra-Navarrete, Carolina, Alba, Ruiz-Cuenca, Castillo, Pablo, Juan & Palomares-Rius, 2024, Unravelling cryptic diversity in the Paratrichodorus allius- group species complex to resolve eight new species of the genus and new insights on the molecular phylogeny % Nematoda: Trichodoridae), Zoological Journal of the Linnean Society 202 (3), pp. 1-44 : 10-12

Paratrichodorus benalupensis sp. nov. Decraemer et al.

( Figs 3C, D , 4 , 5 ; Table 3 )

Zoobank registration: urn:lsid:zoobank.org:act:FB05C936-0F15-4624-997A-9C54782EE924

Type material: Holotype. Male extracted from soil samples collected from the rhizosphere of unidentified grasses at Benalup-Casas Viejas, Cádiz province, southern Spain (36°18 ʹ 24.33 ʹʹ N latitude, 5°52 ʹ 52.38 ʹʹ W longitude) by J. Martín Barbarroja and G. León Ropero, mounted in pure glycerine and deposited in the nematode collection of Ghent University, Ghent, Belgium (slide number UGMD 104450 ).

Paratypes: Male and female paratypes extracted from soil samples collected from the rhizosphere of unidentified grasses at Benalup-Casas Viejas , Cádiz province , southern Spain, were deposited in the following nematode collections: Ghent University, Ghent, Belgium (slide numbers males and female paratype UGMD 104450 , UGMD 104453 ); and one male and one female paratypes at the USDA Nematode Collection, Beltsville, MD, USA (collection number T-8016p ).

Etymology: The species epithet refers to Benalup-Casas Viejas, the type locality where the type specimens were collected.

Description of male: Body nearly straight, cigar-shaped, with swollen cuticle (average 4 µm at midbody) upon fixation; anteriorly clearly tapered to narrower, rounded, low-lip region appearing offset by the protruding double papillae (four cephalic and two subdorsal and two subventral outer labial papillae) and swelling of body cuticle. Onchiostyle rather small (average 37 µm long); reserve onchium (14–17 µm) present in all adults. Pharynx at posterior isthmus either gradually widening to a posterior bulb with a combined short ventral overlap of ventrosublateral pharyngeal glands and short dorsal intestinal overlap; posterior ventrosublateral gland nuclei at some distance from dorsal gland nucleus. Nerve ring surrounding isthmus; SE-pore opposite anterior pharyngeal bulb when pharynx relaxed. A single ventromedian CP at rather short distance (9–15 µm) anterior to SE-pore. Reproductive system monorchic, testis with short germinal zone (34 µm in holotype) and sperm with small, round to oval-shaped nucleus (2.0–2.5 µm × 1.5 µm), closely packed, giving the vesicular seminalis a fibrillar appearance. Spicules medium-sized (average 48 µm), nearly straight, with marked capitulum, blade largely equally wide, transversely striated except anterior end with capitulum and in tapered distal end. Copulatory muscles hardly developed and obscure; capsule of suspensor muscles very thin, around anterior half of spicule; gubernaculum with thickened distal part, parallel to spicules. Bursa narrow, extending largely along spicule region to subterminally on tail. Three precloacal supplements, posterior two (SP1 and SP2) more or less at level of distal half of the retracted spicules with SP1 midway between cloacal opening and SP2; SP3 little developed and non-protruding, located about two spicule lengths from the cloacal opening. A pair of well-developed postcloacal supplements close to the cloacal opening; the anterior cloacal lip bifid with two thin-walled protrusions. Tail short, less than one anal body diameter long and rounded conical. A pair of caudal pores subterminally near tail tip; cuticle slightly thicker at tail tip.

Description of female: Body straight to slightly ventrally curved; largely similar to male, except for reproductive system and male secondary features. Digestive system with a combined dorsal intestinal and a ventral pharyngeal overlap; reserve onchium (12 µm) present in all females. Secretory-excretory pore opposite anterior end of pharyngeal bulb. Reproductive system didelphic-amphidelphic with both branches about equally developed, or one branch longer in the presence of developed oocytes or egg; oviduct cells finely granular; sperm cells, when present, spread along uteri, no spermathecae; vagina more or less barrel-shaped with minor indentation at level of constrictor muscles, about 25% of corresponding body width long; pars refringens vaginae in optical section with minute (1 µm) rounded triangular to oval sclerotized pieces, obliquely oriented, tips separated by 3 µm (average); vulva at about midbody (average 52%). No sublateral/subventral body pores observed.

Code oithin the tabular identification key (based on: Decraemer and Baujard 1998): For males: A 222, B1(2), C2, D1, E0, F3, G2, H3, I4, J1, K2, L2, M27, N5, O1, P1. For females: A222, B12, C1, D1, E3, F4, G-, H33, I1, J1, K12, L3, M1, N1, O2, P2, Q4, R2, S1, T1.

Diagnosis and relationships: Paratrichodorus benalupensis sp. nov. is characterized by body medium-sized (average 900 µm in female; 775 µm in male), onchiostyle medium-sized (average 41 µm in female, 39 µm in male), and all adults with a reserve onchium. Male with a single CP, shortly anterior to SE pore; straight spicules with marked capitulum, small sperm cells with clear nucleus closely packed giving fibrillar appearance and thereby giving the vas deferens a striated appearance; three precloacal supplements, the posterior two more or less at level of the posterior half of the retracted spicules; a pair of postcloacal supplements near cloacal opening; the latter with pronounced bifid anterior lip. Females with vulva more or less barrel-shaped, about 25% of corresponding body width long; vaginal sclerotized pieces in optical section minute (1 µm), rounded triangular to oval shaped, obliquely oriented, tips separated by 3 µm (average). Sperm spread over uteri. No sublateral/subventral body pores observed.

Use of the tabular identification key for Paratrichodorus males (based on Decraemer and Baujard 1998) and sorting by primary feature D, followed by feature N (sperm cells), grouped the P. benalupensis sp. nov. together with P. catharinae , P. meyeri , P. paraporosus , P. tunisiensis , and the previously described new species P. uliaensis sp. nov.. It differs from the known species (except P. paraporosus ) by the shorter onchiostyle ≤40 µm vs.>40 µm and from P. tunisiensis also in spicule shape [straight vs. more curved (type population, populations from Italy; Siddiqi 1963, Roca and Lamberti 1984, Tanha Maafi and Decraemer 2002)] and from P. paraporosus in the presence of only three SP instead of four SP. Paratrichodorus benalupensis sp. nov. can be distinguished from all four species by the presence of a reserve onchium in the adult. The presence of a reserve onchium in the adult is the main feature to distinguish it from P. uliaensis sp. nov..

For females of the Benalup sample, sorting on primary features D and C, followed by L and K (variable), resulted in a classification in subgroups 1-11 or 1-12 in Decraemer and Baujard (1998); further sorting on feature P (type of sperm cells) and feature N (occurrence of males) groups P. benalupensis sp. nov. with P. acaudatus and P. tunisiensis , P. lobatus (Colbran 1965 ) Siddiqi 1974, and the previously described P. uliaensis sp. nov.. The new species differs from all these species by the presence of a reserve onchium in the adult and from all known species by the shorter onchiostyle, a feature it has in common with the previously described new species. So far, the presence of a reserve onchium in all specimens of a population has only been used as a diagnostic feature in the genus Nanidorus to differentiate Nanidorus minor and N. nanus ( Allen 1957 ) Siddiqi 1974 from the other species. In all other examples this criterion is considered as accidental (see Discussion). Except for the presence of a reserve onchium in the adult of P. uliaensis sp. nov., this species is almost undistinguishable morphologically from P. benalupensis sp. nov., being described here as separate new species, based on the additional support given by morphometrical and molecular analyses (see below).

Figures

Figure 3. Line drawings for comparison of vagina in the Paratrichodorus allius species-complex group. A* B* P. uliaensis sp.nov.; C* D. P. benalupensis sp. nov.; E* P.hinogerus sp. nov.; F* G* P.tarifaensis sp. nov.; H* P.asidonaensis sp.nov.; I* P. rocianerus sp. nov.; J* P.litoralis sp. nov.; K* L* P. paraallius sp. nov.; M–P* P.allius based on Sturhan %1989); Q* P.allius* paratype; R* S* P.teres* paratypes.

Figure 4. Line drawings of Paratrichodorus benalupensis sp. nov.. Male.A* pharyngeal region.B* C* E* tail region with copulatory apparatus. E* in ventral view. D* testis* partim.Female paratype. F* pharyngeal region.G* vagina region. C* D* holotype. Scale bars = 20 µm.

Figure 5. Light micrographs of Paratrichodorus benalupensis sp. nov.. A* anterior body region. D* testis with germinal zone.E* region pharyngointestinal junction.F–H* posterior body region of male holotype with focus on spicule* gubernaculum and bursa respectively.Female paratype. B* anterior body region. C* vagina region.Scale bars A–H = 10 µm.