Paratrichodorus hinogerus, 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 : 13-17

Paratrichodorus hinogerus sp. nov. Decraemer et al.

( Figs 3E , 6 , 7 ; Table 4 )

Zoobank registration: urn:lsid:zoobank.org:act:58A44816-941D-4441-8693-C448933A14E3

Type material: Holotype. A female was chosen as holotype because males were rare; only two males (one in dorso-ventral position) were found among 23 females and juveniles. Female extracted from soil samples collected from the rhizosphere of stone pine ( Pinus pinea ) at Hinojos, Huelva province, southern Spain (37°17 ʹ 42.2 ʹʹ N latitude, 6°23 ʹ 46.0 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 104451 ).

Paratypes: Male and female paratypes extracted from soil samples collected from the rhizosphere of stone pine at Hinojos , Huelva province , southern Spain, were deposited in the following nematode collections: Ghent University, Ghent, Belgium (slide numbers male and females paratype UGMD 104451-104452 ); and one female paratype at the USDA Nematode Collection, Beltsville, MD, USA (collection number T-8017p ).

Additional material examined: Additional populations were collected also in the rhizosphere of wild olive at Sanlúcar de Barrameda , Cádiz province, Spain (36°51 ʹ 20.0 ʹʹ N latitude, 6°19 ʹ 13.6 ʹʹ W longitude), and the rhizosphere of cork oak ( Quercus suber ) at Bonares, Huelva province, Spain (37°14 ʹ 11.1 ʹʹ N latitude, 6°40 ʹ 34.7 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 refers to the name of the inhabitants of Hinojos, the type locality where the type specimens were collected.

Description of female: Body medium-sized (average 730 µm), more or less straight cigar-shaped or slightly curved ventrad, often with swollen cuticle (4–7 µm at midbody) upon fixation; anteriorly tapered to a narrower, rounded lip region with protruding double papillae (four cephalic and two subdorsal and two subventral outer labial papillae). Onchiostyle rather long (average 56 µm long). Pharynx with a short narrower part (isthmus), slightly widening in front of a more or less marked posterior bulb, with a ventral overlap of the ventrosublateral pharyngeal glands as well as a dorsal overlap by the intestine; posterior ventrosublateral gland nuclei close to pharyngo-intestinal junction and far from the dorsal gland nucleus situated at the anterior end of the bulb. Nerve ring surrounding isthmus; SE-pore opposite anterior pharyngeal bulb. Reproductive system didelphic-amphidelphic with both branches more or less equally developed, with the posterior branch usually slightly shorter; influenced by difference in development of ovarial sac with presence of sperm; oviduct cells finely granular. Vagina short (less than one-fifth of corresponding body width), rounded with midway indentation and surrounded by narrow constrictor muscles; pars refringens vaginae in optical section with minute (1–1.5 µm) narrow triangular sclerotized pieces, slightly obliquely oriented, tips separated by 2–3 µm; vulva at about midbody (average 56%); a longitudinal slit in ventral view. No sublateral/subventral body pores. Tail minute, terminal cuticle slightly thicker; a pair of caudal pores present. The populations from Sanlúcar de Barrameda also showed females with sperm at level ovarial sac, similar sclerotized pieces in size, shape, location, very short vagina (<20% of corresponding body diameter), similar long onchiostyle (60–62 µm) but body on the higher range (longer body) (average 980 µm for three females in sample code AR016; 830 µm, in sample code AR015, one female) and slightly more anterior vulva position with V% in AR016 of 53–54%.

Description of male: Largely similar to female, apart from reproductive system, male secondary features and a somewhat longer tail. Onchiostyle equally long and pharynx with clear ventral pharyngeal overlap (18 µm) and shorter (10 µm) dorsal overlap by intestine. Secretory-excretory pore opposite anterior pharyngeal bulb but posterior to a single ventromedian cervical papilla; no lateral cervical papillae observed. Reproductive system monorchic, testis with very short germinal zone (12 µm) and sperm with small, oval-shaped nucleus (2.0–2.5 × 1µm). Spicules medium-sized, slightly ventrally curved, hardly marked equally wide capitulum; blade largely equally wide, tapering slightly anteriorly, more pronounced posteriorly and transversely striated, except for extremities. Copulatory muscles hardly developed, restricted to region of retracted spicules; capsule of suspensor muscles very thin, enclosing anterior half of spicule; gubernaculum with thickened distal part, parallel to spicules. Bursa narrow, extending from just posterior of spicule head to subterminally on tail. Three precloacal supplements, posterior two (SP1 and SP2) opposite retracted spicules with SP1 at about equal distance from cloacal opening and from SP2; SP3 little developed and non-protruding, located about 2.5 spicule lengths from the cloacal opening. A pair of well-developed postcloacal supplements close to the cloacal opening, the latter with a small protruding anterior lip flap (in ventral view visible as two flaps bordering the opening). Tail short, less than one anal body diameter long and rounded conical. A pair of posterior caudal pores subterminally near tail tip.

Code oithin the tabular identification key (based on: Decraemer and Baujard 1998): For males: A 222, B2, C2, D1, E0, F3, G2, H3, I4, J2, K23, L2, M27, N2, O1, P1. For females: A212 (average, min., max), B2(3), C1, D1, E3, F4, G3, H53, I1, J3, K2, L3, M1, N2, O32, P2, Q4, R2, S1, T1.

Diagnosis and relationships: Paratrichodorus hinogerus sp. nov. is characterized by a medium-sized body (average about 730 µm, type population) and rather long onchiostyle (56 µm average in female, 58 µm in male) in both sexes. Females possess a very short (less than one-fifth corresponding body width) rounded vagina with minute, narrow, triangular sclerotized pieces, obliquely orientation and clearly separated from one another. Reflexed ovaries often with a long ovarial sac filled with sperm. No sublateral/subventral body pores observed. Males rare compared to females and possess a single ventromedian cervical papilla, testis with small sperm cells and small nucleus, medium-sized spicules (48 µm) with slightly marked capitulum, blade finely striated and three precloacal supplements with the posterior two spread along the retracted spicules.

Based upon the tabular identification keys for males (Decraemer and Baujard 1998), sorting of the data primarily on character D (number of CP), followed by feature N (type of sperm cells), groups the new species with the known species P. catharinae , P. meyeri and P. tunisiensis and with former new species described P. uliaensis sp. nov. and P. benalupensis sp. nov.. It differs from all these species by male being rare and by a longer onchiostyle (>55 µm average) and in addition from P. benalupensis sp. nov. by absence of reserve onchium.

For females, sorting on primary features D, C, and K and L of the tabular identification key followed by, feature P (type of sperm cell) and by feature N (occurrence of males) groups the new species with the known species P. allius and P. teres . As in P. allius males are rare or absent in most populations of P. teres . Paratrichodorus hinogerus sp. nov. also agrees with P. allius in the presence of sperm in the ovarial sac vs. along the uteri in P. teres and in the narrow triangular, slightly oblique vaginal sclerotized pieces and vagina barrel-shaped, slightly indented at level of narrow constrictor muscles. In P. teres vaginal sclerotized pieces are more oval or rounded triangular and the vagina mostly shows midway a widening ( Fig. 3 ). Paratrichodorus hinogerus sp. nov. is also distinguished from these species by a longer onchiostyle (averages 56 µm vs. 42.5 µm and 45 µm, respectively).

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 6. Line drawings of Paratrichodorus hinogerus sp. nov.. Male paratype.A* pharyngeal region.B* posterior body region.C* reproductive system and tail region. Female.D* pharyngeal region* paratype. E* vagina region paratype.G* reproductive system holotype. F* tail region* holotype.Scale bars = 20 µm.

Figure 7. Light micrographs of Paratrichodorus hinogerus sp.nov.. A–D* male paratype. A* total view. B* testis* germinal zone. C* tail region and copulatory apparatus. D* bursa %arrow).E–I* females.E* total view paratype.F* pharyngeal region. G-H* vagina region. I* reproductive system in holotype* arrow point to ovarial sac with sperm. Scale bars A* E = 100 µm; B–D* F–I = 20 µm.