Paratrichodorus rocianerus, 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 : 25-28

Paratrichodorus rocianerus sp. nov. Decraemer et al.

( Figs 3I , 12 , 13 ; Table 7)

Zoobank registration: urn:lsid:zoobank.org:act:8C8E441C-8A02-4028-93A6-1DA83FF06626

Type material: Holotype. Male extracted from soil samples collected from the rhizosphere of grapevine ( Vitis vinifera ) at Rociana del Condado, Huelva province, southern Spain (37°19 ʹ 51.0 ʹʹ N latitude, 6°35 ʹ 54.9 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 104462 ).

Paratypes: Male and female paratypes extracted from soil samples collected from the rhizosphere of grapevine at Rociana del Condado , Huelva province , southern Spain, were deposited in the following nematode collections: Ghent University, Ghent, Belgium (slide numbers males and females paratype UGMD 104463-104466 ); and one male and one female paratypes at the USDA Nematode Collection, Beltsville, MD, USA (collection number T-8020p ).

Etymology: The species epithet refers to the name of the inhabitants of Rociana del Condado, the type locality where the type specimens were collected.

Description of male: Body straight, cigar-shaped, often with swollen cuticle (4.5–6.0 µm at midbody) upon fixation; anteriorly tapered to rounded lip region appearing offset by the protruding double papillae (four cephalic and two subdorsal and two subventral outer labial papillae). Onchiostyle rather short (average 39 µm long). Pharynx at posterior isthmus gradually widening to a posterior bulb, with a pronounced (24–27 µm) ventral overlap of the ventrosublateral pharyngeal glands; dorsal gland nucleus in the anterior third of bulb. Nerve ring surrounding isthmus; SE-pore opposite posterior part pharyngeal bulb. Ventromedian and lateral cervical papillae absent. Reproductive system monorchic, testis with geminal zone 29 µm in holotype; sperm small with oval-shaped nucleus, 5 by 3 µm in size. Spicules medium-sized (average 45 µm), nearly straight, with short widened 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, around anterior half of spicule; gubernaculum with thickened distal part, parallel to spicules. Bursa narrow, extending from head of retracted spicule to subterminal on tail. Three precloacal supplements, posterior two (SP1 and SP2) papilliform opposite distal half of retracted spicules; SP3, little developed and non-protruding, located about 2.5 spicule lengths from the cloacal opening. A pair of postcloacal supplements shortly posterior to the cloacal opening, the latter with a small protruding anterior lip flap (in ventral view visible as two flaps bordering the opening). Tail less than one anal body diameter long (c’ average 0.64) and broad conical. A pair of posterior caudal pores subterminally near tail tip. Cuticle at tail tip not thickened (2.0 µm).

Description of female: Body slightly longer than in male; pharynx with a clear dorsal intestinal overlap (48 µm in one female) and with both an intestinal dorsal (45 µm) and a pronounced ventral overlap of pharyngeal glands (72 µm) in another female. Reproductive system with small sperm all along the uteri; vagina short (16% of cbd) with minor indentation at level of weak vaginal constrictor muscles; vaginal sclerotization pieces small (1–1.5 µm), oval, well separated (2.5–4.5 µm) and almost parallel to vaginal lumen in orientation. A postvulvar lateral body pore observed at 111 µm posterior to vulva. Tail minute, caudal pores nearly terminal on tail.

Code oithin the tabular identification key (based on: Decraemer and Baujard 1998): For male: A222 (average, min., max.), B12, C22, D0, E0, F3, G2, H4, I2, J1, K2, L2, M27, N2, O1, P1(3). For female: A223, B22, C1, D1, E4, F34, G?, H5, I1, J3, K2, L3, M3, N1, O2, P2, Q?, R21, S1, T1.

Diagnosis and relationships: Paratrichodorus rocianerus sp. nov. is characterized by a medium-sized to large body (average 825 µm in male; 975 µm in female), medium-sized onchiostyle (average 38.5 µm in male, 43 µm in female), absence of ventromedian and lateral cervical papillae in male, small sperm with oval nucleus, overlaps pharynx–intestinal junction variable, medium-sized spicule length (average 45 µm) with finely striated, slightly ventrally curved and short marked capitulum, three precloacal supplements, of which the posterior two opposite posterior half retracted spicule, tail clearly shorter than anal width, with a pair of postcloacal supplements shortly posterior to the cloacal opening and nearly terminal pair of caudal pores. Females with short vagina (16% cbd) with minor indentation and small oval vaginal sclerotized pieces (1.0–1.5 µm) in optical section, parallel with vaginal lumen and clearly separated, sperm in uteri.

Based upon the tabular identification key for Paratrichodorus males (Decraemer and Baujard 1998), sorting of the data primarily on character D, followed by character F (number SP) groups the new species with the known species P. teres , P. rhodesiensis , P. lobatus (partim 3SP), and the previously described new species P. tarifaensis sp. nov. and P. asidonaensis sp. nov. Paratrichodorus rocianerus sp. nov. differs from P. teres by a different sex ratio (male as common as female vs. male absent or rare in most populations of P. teres ), by a slightly shorter onchiostyle (37–40 µm vs.>40 µm) and non-fibrillar sperm. It can be differentiated from P. lobatus by a slightly shorter onchiostyle 37–40 µm vs.>40 µm, shorter spicules (44–46 µm vs. 53–59 µm) and from P. rhodesiensis by a slightly longer body (average 825 µm vs. 645 µm in type population) and smaller c’ value (<1 instead of> 1 in P. rhodesiensis ) and by the pronounced ventral overlap of the pharyngeal glands vs. a slight overlap; the single much smaller male specimen (360 µm) with 1 CP described in Baujard (1983) from Ivory Coast could represent a different species. It differs from P. asidonaensis sp. nov. by males being as common as females, by longer body and spicules, comparable with P. tarifaensis sp. nov., but differs from the latter by a longer onchiostyle and more posterior position of EP-pore.

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 presence of males joins the new species P.s rocianerus sp. nov. with P. acaudatus , and previously described species P. tarifaensis sp. nov. and P. benalupensis sp. nov.. Paratrichodorus rocianerus sp. nov. differs from P. acaudatus in the subterminal position of the anus vs. terminal and from both P. acaudatus and P. tarifaensis sp. nov. in the shorter onchiostyle (41–45 µm vs. 82–83 µm and 50–57 µm, respectively) and in shape of vaginal sclerotized pieces (small oval vs. quadrangular and small triangular, respectively). Females can hardly be distinguished from P. benalupensis sp. nov. except for the absence of reserve stylet vs. present. Features L and K appear to be variable (difficult to describe precisely or illustrate because of their minute size in optical section).

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 12. Line drawings of Paratrichodorus rocianerus sp. nov.. Holotype male.A* pharyngeal region.B* posterior body region.C* testis germinal zone. Female paratype.E* pharyngeal region.F* anterior branch reproductive system. D* tail region. Scale bars = 20µm.

Figure 13. Light micrographs of Paratrichodorus rocianerus sp. nov.. Male holotype. A* total view.B* posterior body region with copulatory apparatus. C* tail region with spicule.D* tail region showing bursa %arrow). Female paratypes.E* anterior body region. F* G* vagina region. H* reproductive system.I. tail region. Scale bars A = 100 µm; B = 20 µm; C–G* I = 10 µm; H = 30 µm.