Paratrichodorus litoralis, 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 : 29

Paratrichodorus litoralis sp. nov. Decraemer et al.

( Figs 3J , 14 , 15 ; Table 8)

Zoobank registration: urn:lsid:zoobank.org:act:B7070089-B833-43C5-B38C-CF4112497D1B

Type material: Holotype. Male extracted from soil samples collected from the rhizosphere of marram grass ( Ammophila arenaria ) at Pantanagianni, Brindisi province, southern Italy (40°45 ʹ 01.27 ʹʹ N latitude, 17°43 ʹ 13.65 ʹʹ E longitude) by N. Vovlas, mounted in pure glycerine and deposited in the nematode collection of Ghent University, Ghent, Belgium (slide number UGMD 104467 ).

Paratypes: Male and female paratypes extracted from soil samples collected from the rhizosphere of marram grass at Pantanagianni , Brindisi province , southern Italy, were deposited in the following nematode collections: Ghent University, Ghent, Belgium (slide numbers males and females paratype UGMD 104467-104469 , UGMD 104461 ); and one male and one female paratypes at the USDA Nematode Collection, Beltsville, MD, USA (collection number T-8021p ).

Additional material examined: An additional population was collected also in the rhizosphere of marram grass at Cullera, Valencia province, Spain (39°15 ʹ 64.7 ʹʹ N latitude, 0°24 ʹ 08.2 ʹʹ W longitude); unfortunately the specimens of this population were not in good conditions for light microscopic study, and were identified only molecularly.

Etymology: The species epithet 8s derived from the Latin litoralis = pertaining to the seashore, and refers to the coastal environment where the type specimens were collected.

Description of male: Body nearly 750 µm long (average) straight, cigar-shaped, with cuticle swollen upon fixation (5 µm at midbody); anteriorly 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 long (average 56 µm long); reserve onchium (21.5 µm average) present in all adults. Pharynx at posterior isthmus gradually widening to a posterior bulb and a short dorsal overlap by the intestine. Nerve ring surrounding isthmus; SE-pore opposite isthmus. Ventromedian or lateral cervical papillae absent. Reproductive system monorchic, sperm small with oval-shaped nucleus (3.0 × 1.5 µm). Spicules medium-sized (average 54.5 µm), slightly ventrally curved, with short slightly wider capitulum, blade largely equally wide but slightly tapered towards an open distal tip; spicules ornamented with fine, transverse striae, except at extremities. Copulatory muscles hardly developed, obscure; capsule of suspensor muscles thin, surrounding anterior half of spicule; gubernaculum with thickened distal part parallel to spicules. Bursa narrow, extending usually from head of retracted spicule to subterminally on tail. Three precloacal supplements, posterior two (SP1 and SP2) opposite distal two-thirds of retracted spicules; anteriormost SP3, little developed and non-protruding, located about 2.5 spicule length anterior to retracted spicules. A pair of well-developed postcloacal supplements close to the cloacal opening; cloacal lips may be slightly protruding. Tail short, less than one anal body diameter long, conical. A pair of caudal pores subterminally near tail tip.

Description of female: Body similar in appearance and size as in male, except for male reproductive system and features. Onchiostyle equally long, with a reserve stylet in adults; pharyngo-intestinal junction with dorsal overlap 16–24 µm, rarely combined with a short ventral overlap. Reproductive system with both genital branches about equally long and without spermatheca but small sperm with small nucleus spread over the uteri; vagina barrel-shaped with minor indentation at level weak constrictor muscles; vaginal sclerotization pieces very small (1.0 µm), rounded triangular, clearly apart (2.0–3.0 µm), slightly oblique and vulva a longitudinal slit in ventral view. Tail with caudal pores.

Code oithin the tabular identification key (based on: Decraemer and Baujard 1998): For male: A212 (average, min., max.), B22, C22, D0, E0, F3, G2, H2, I4, J2, K2, L2, M27, N2, O1, P1. For female: A222 (200), B23, C1, D1, E2, F3(4), G3, H3, I1, J1, K1, L3, M1, N1, O2, P2, Q-, R2, S1, T1.

Diagnosis and relationships: Paratrichodorus litoralis sp. nov. is characterized by a medium-sized body (average 740 µm in male, 790 µm in female), rather long onchiostyle (average 57 µm in male, 60 µm in female), absence of ventromedian and lateral cervical papillae in male, spicule length average 55 µm, three precloacal supplements with the posterior two opposite the distal two-thirds of the retracted spicules. Females with barrel-shaped vagina, one-fifth of corresponding body width, and with minor indentation; minute vaginal sclerotized pieces (1 µm), slightly oblique and clearly separated (2.2–3 µm); sperm spread over uteri. Both sexes with a reserve onchium in adults, dorsal overlap by the intestine and caudal pores present.

Based upon the tabular identification key for Paratrichodorus males (Decraemer and Baujard 1998), sorting of the data primarily on character D (number of ventromedian cervical papillae), followed by character F (number of precloacal supplements) groups P. litoralis sp. nov. with the known species P. allius , P. teres , and P. rhodesiensis , and with previously described P. tarifaensis sp. nov. that shows similar measurements of body length, onchiostyle, and spicule length. It also groups with P. lobatus and P. namibiensis (partim) with males with exceptionally 3 SP. Paratrichodorus litoralis sp. nov. differs from all by the presence of a reserve onchium in the adult, and from P. teres , P. namibiensis , and P. lobatus in the non-fibrillar appearance of sperm vs. thread-like or fibrillar. The new species also differs from all known species by the longer onchiostyle (average>55 µm vs. <55 µm) and by the longer spicule length than in P. allius , P. rhodesiensis , and P. teres (average>50µm vs. <50 µm) but similar as in P. lobatus and shorter than in P. namibiensis (average 67 µm).

Based upon the tabular identification keys for females (Decraemer and Baujard 1998), sorting on primary features D and C, followed by L and K, resulted in a classification in subgroup 1-12 of group 1. Further sorting on feature P (type of sperm cell), feature O (location of sperm) and feature N (presence of males) groups P. litoralis sp. nov. with known species P. acaudatus and P. allius . Paratrichodorus litoralis sp. nov. differs from both by the presence of a reserve onchium in adult, a feature it has in common with P. benalupensis sp. nov.. It further differs from P. allius by the longer onchiostyle (58–64 µm vs. 37–48 µm), the longer spicules (50–58 µm vs. 31 µm), the male–female ratio, with males as common as females vs. males rare, and by the short dorsal overlap by the intestine vs. a ventral overlap in P. allius .

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 14. Line drawings of Paratrichodorus litoralis sp. nov.. A* total view female paratype. B* pharyngeal region female paratype. C* tail region and copulatory apparatus* male paratype.D* protruding spicule* paratype. E* posterior body region* holotype male.F* pharyngeal region paratype male.G* female reproductive system* paratype.H* testis* germinal zone* paratype. Scale bars = 20 µm.

Figure 15. Light micrographs of Paratrichodorus litoralis sp. nov.. A* total view paratype female.B* anterior body region* arrow points to reserve onchium* paratype female. C* vagina region* paratype. D* posterior genital branch* paratype female.E* anterior body region* arrow points to reserve onchium* paratype male; tail region with copulatory apparatus* holotype male. Scale bars A = 100 µm; B* E = 20 µm; C* D = 10 µm.