Zoosyst. Evol. 101 (2) 2025, 571-581 | DOI 10.3897/zse.101.144719 eee BERLIN Retrieval of the genus Capitellus Siddiqi, 1983, with description of C. caramborum sp. nov. (Dorylaimida, Belondiridae) associated with Andalusian (Spain) olive groves Miriam Garcia-Ruiz', Joaquin Abolafia!, Reyes Pefia-Santiago* 1 Departamento de Biologia Animal, Biologia Vegetal y Ecologia, Universidad de Jaén, Jaén, Spain 2 Retired Professor, Universidad de Jaén, Jaén, Spain https://zoobank. org/2F62AE4E-8CBC-452E-A01F-23ECC9DDIBCB Corresponding author: Miriam Garcia-Ruiz (migarcir@ujaen.es) Academic editor:A. Schmidt-Rhaesa # Received 17 December 2024 Accepted 9 January 2025 Published 28 February 2025 Abstract A new species of belondirid nematode, collected in olive groves of the southern Iberian Peninsula, is described, including SEM observations and molecular (LSU, SSU) study. Capitellus caramborum sp. nov. 1s characterized by its 0.82—1.09 mm long body, lip region offset by constriction and 6.0—6.5 um wide with a distinct perioral refractive disc 4.0-4.5 um wide, odontostyle 6.0-6.5 um long, odontophore bearing basal flanges and 1.8—2.0 times the odontostyle long, neck 223—296 um long, pharyngeal expansion oc- cupying 53-59% of the total neck length, female genital system diovarian, uterus simple and 27-38 um or 1.4—1.9 body diameters long, vulva (V = 53-56) longitudinal, tail convex conoid to subcylindrical (24-34 um, c = 31-38, c’ = 1.8-2.1), spicules strongly curved ventrad and 23—25 um long, and four ventromedian supplements. Morphological and molecular data support the retrieval of Capitellus as a valid genus, its taxonomy being updated, including the transference of Dorylaimellus neocapitatus to It. Key Words Description, dorylaims, LSU, morphology, nematodes, new combination, phylogeny, SSU, taxonomy Introduction In his revision of the subfamily Dorylaimellinae Jairaypu- ri, 1964, Siddiqi (1983) proposed the new genus Capitel- Jus to transfer Dorylaimellus capitatus Siddiqi, 1964, as its only and type species. Siddiqi (op. cit.) also stated that Capitellus was (p. 4) unique among the Dorylaimellinae in having a continuous lip region and an angular, “refrac- tive perioral disc,” thus putting especial emphasis on the relevance of this peculiar feature as its most recognizable diagnostic trait. Besides, Capitellus was characterized by its indistinct perioral sclerotized pieces, diovarian female genital system, and subcylindrical tail. Jairajpuri and Ah- mad (1992) admitted Capite/lus as a valid taxon but low- ered its category to a subgeneric level under the genus Dorylaimellus Cobb, 1913; meanwhile, Andrassy (2009) considered both taxa to be identical. Available information about the type and only species, C. capitatus (Siddiqi, 1964) Siddiqi 1983, is limited to a rather simple original description and illustrations based on eleven females collected from soil around roots of mango at Kareli, Madhya Pradesh, India. Moreover, Sid- diqi (1983) reported its presence in other territories and habitats: Pakistan, lucerne soil in Tanzania, and banana soil in Trinidad; nevertheless, the author did not provide further data about these populations. Peralta and Pefia-Santiago 2000 (see _ also Jiménez-Guirado et al. 2007) described Dorylaimel- lus neocapitatus from several locations of the southern Iberian Peninsula, Spain, associated with Mediterranean brushwood (Ulex parviflorus Poutr., Echinospartum bois- sieri (Sapch) Rothm., Retama sp., Chamaerops humilis L., Pistacia lentiscus L., Foeniculum vulgare Mill., and Lavandula stoechas Lam.), but also with almond groves Copyright Garcia-Ruiz, M. et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 572 Garcia-Ruiz, M. et al.: Retrieval of Capitellus and description of C. caramborum from Spain and a wheat field. This species shared with C. capitatus the presence of a refractive perioral disc and other fea- tures of their general morphology, but it was easily sepa- rable from this in several relevant morphometrics. Two populations of a Dorylaimellinae taxon were col- lected in the course of a nematological survey conducted to study the free-living fauna inhabiting olive soils in the framework of the project Soi/ O-Live (EU Horizon Pro- gram grant No 101091255). Its morphological and molec- ular study revealed that it belonged to an unknown form very similar to C. capitatus and D. neocapitatus. Thus, this contribution aims to describe it, to obtain its molec- ular characterization, and to discuss its evolutionary rela- tionships. The results are presented in the following. Materials and methods Nematodes and their morphological and morphometrical study A total of 20 specimens found in soils of olive groves were available to study. Nematodes were extracted by centrifugation (CDFA 2015, based on Jenkins 1964) and/ or with Baermann’s funnels following the protocol by Flegg (1967); somewhat modified, killed by heat, fixed in 4% formaldehyde, preserved in anhydrous glycerin according to Siddiqi’s (1964b) method, mounted on per- manent glass slides that were sealed with paraffin, and measured and photographed using an Eclipse 801 micro- scope (Nikon) equipped with differential interference contrast optics, a drawing tube (camera lucida), and a DS digital camera. Morphometrics include Demanian indices (de Man, 1880) and other measurements and ratios, some of them presented in a separate table, while others form part of the literal description of species. Two specimens preserved in glycerin were selected for observation with a SEM according to Abolafia (2015). The nematodes were hydrated in distilled water, dehydrated in a graded etha- nol—acetone series, critical point dried, coated with gold, and observed with a Zeiss Merlin microscope (5 kV). Molecular study For molecular analyses, single specimens were tem- porarily mounted in a drop of 1 M sodium chloride containing glass beads. This was followed by DNA extraction from single individuals as described by Ar- chidona-Yuste et al. (2016). The D2—D3 domains were amplified using the D2A (5'-ACAAGTACCGTGAG- GGAAAGTTG-3') and D3B (5'-TCGGAAGGAAC- CAGCTACTA~3’) primers (Nunn, 1992; De Ley et al., 1999). The portion of 18S rRNA was amplified using primers 988F (5'-CTCAAAGATTAAGCCATGC-3’), 1912R (5'-TTTACGGTCAGAACTAGGG-3’), 1813F (5'-CTGCGTGAGAGGTGAAAT~-3’), and 2646R (5'— GCTACCTTGTTACGACTTTT-—3') (Holterman et al. zse.pensoft.net 2006). All polymerase chain reaction (PCR) assays were done according to the conditions described by Archido- na-Yuste et al. (op. cit.). The amplified PCR products were purified using ExoSAP-IT (Affimetrix, USB prod- ucts) and used for direct sequencing on a DNA multi- capillary sequencer (Model 3130XL genetic analyzer; Applied Biosystems, Foster City, CA, USA), using the BigDye Terminator Sequencing Kit V.3.1 (Applied Bio- systems, Foster City, CA, USA), at the Stab Vida sequenc- ing facilities (Caparica, Portugal) according to the Sanger et al. (1977) method. The newly obtained sequences were submitted to the GenBank database under the accession numbers indicated on the phylogenetic trees. Phylogenetic analyses For phylogenetic relationships, analysis was based on 18S and 28S rDNA fragments. The obtained sequences were manually edited using Chromas 2.6.6 (Technely- sium) and aligned with other rDNA sequences available in GenBank using the ClustalW alignment tool imple- mented in MEGA7 (Kumar et al. 2016). Poorly aligned regions at extremes were removed from the alignments using MEGA7. The best-fit model of nucleotide substi- tution used for the phylogenetic analysis was statistically selected using jModelTest 2.1.10 (Darriba et al. 2012). The phylogenetic tree was generated with the Bayesian inference method using MrBayes 3.2.6 (Ronquist et al. 2012). Romanomermis culicivorax Ross & Smith, 1976 (DQ418791 and EF417153, for the 18S and 28S rDNA trees, respectively) was chosen as an outgroup. The anal- ysis under the General Time Reversible plus Invariant sites plus Gamma distribution (GTR + I + G) model was initiated with a random starting tree and run with the Markov chain Monte Carlo (MCMC) (Larget and Simon 1999) for 1 x 10° generations. A total of 25% of samples was discarded as burn-in. The tree was visualized and saved with FigTree 1.4.4 (Rambaut 2018). Results Capitellus caramborum sp. nov. https://zoobank.org/4B2DFECC-F 1DC-490A-AF08-47C3CDB1C121 Figs 1-4 Material examined. Fourteen females and six males from two locations, in variable states of preservation. Morphometrics. See Table 1. Description. Baena (type) population: Adult. Slender (a = 40-49) nematodes of small to medium size, 0.82-1.04 mm long. Body cylindrical, tapering towards both extremities. Upon fixation, habi- tus regularly curved ventrad, often adopting an open C shape. Cuticle dorylaimid, two-layered, thin, ca 1 um thick throughout the entire body, outer layer bearing very fine transverse striation, better observable with SEM. Zoosyst. Evol. 101 (2) 2025, 571-581 573 Table 1. Main morphometrics of Capitellus species. Measurements in um except L in mm, and in the form: average + sd (range). Species C. caramborum sp. nov. C. capitatus | C. neocapitatus Population Baena Antequera Type Several Country Spain Spain India Spain Holotype Paratypes n 2 720 633 629 hee 2329 Character L 0.98 0.94 + 0.05 (0.88-1.04) | 0.88 + 0.05 (0.82-0.94) | 1.04 + 0.50 (0.97-1.09) | 0.58-0.65 0.75-0.99 a 47 45.3 + 3.1 (40-49) 45.3 + 3.1 (40-49) 48.7 + 2.3 (44-51) 30-37 35-42 b 3:6 3.7 + 0.2 (3.5-4.1) 3.7 + 0.2 (3.5-4.1) 3.7 + 0.1 (3.6-3.9) 2./-3.3 2./-3.7 C 34 35.0 + 2.3 (31-38) 35.0 + 2.3 (31-38) 34.0 + 2.0 (32-36) 21-25 28-39 V 54 54 + 1.0 (53-56) 54.0 + 1.0 (53-56) 54-56 52-59 Cc’ 2.0 1.9 + 0.1 (1.8-2.0) 2.1 + 0.1 (2.0-2.1) 2.1 + 0.1 (1.9-2.1) 252) 1.3-1.7 Lip region diameter 6.5 6.3 + 0.2 (6.0-6.5) 6.3 + 0.3 (6.0-6.5) 6.3 + 0.3 (6.0-6.5) ? 6.5-7.5 Odontostyle length 6.0 6.1 + 0.2 (6.0-6.5) 6.1 + 0.2 (6.0-6.5) 6.3 + 0.3 (6.0-6.5) 4.5 5.0-5.5 Odontophore length 12 11.9 + 0.4 (11.5-12.5) 12.1 + 0.3 (12-12.5) 12.1 + 0.5 (11.5-12.5) 13-14 10-12 Neck length 268 253 + 14 (225-268) 248 + 25 (223-283) 282 + 17 (252-296) 217 221-278 Pharyngeal expansion 143 137 + 14 (106-155) 134 + 16 (111-158) 153 + 19 (118-174) bes 131-159 length Body diameter at neck 21 21.0 + 0.9 (20-23) 20.1 + 0.8 (19-21) 21.6 + 1.1 (20-23) ? 20-26 base mid-body Zi 20.9 + 1.0 (20-23) 19.9 + 0.7 (19-21) 21.3 + 0.8 (20-22) 20! 21-28 anus/cloaca 14 14.9 + 0.7 (14-16) 15.9 + 0.5 (15-17) 14.9 + 0.6 (14-16) 12! 15-18 Distance vulva - 529 512 + 34 (464-574) = 562 + 27 (522-595) 354! 420-533 anterior end Prerectum length 90 94.5 + 3.0 (90-96) 72.4 + 9.9 (58-79) 94.6 + 3.1 (92-98) ? 62-98 Rectum/cloaca length 19 18.7 + 1.3 (17-20) ? 19.4 + 0.2 (19-20) ? 12-18 Tail length 29 27.0 + 1.7 (24-29) 33.0 + 1.0 (32-34) 30.6 + 1.0 (29-32) 26 23-28 Spicules length - - 24.3 + 0.8 (23-25) = = = Ventromedian - - 4 - - - supplements Lateral chord 6.0-6.5 um wide, occupying less than one- third (26-31%) of mid-body diameter, bearing abundant granular gland bodies. Body pores abundant, appearing as (SEM observations, Fig. 4J) short longitudinal slits. Lip region cap-like, offset by constriction, 1.7—2.0 times as wide as high and up to one-third (28-33%) of body di- ameter at neck base, with a well-differentiated, refractive perioral disc; SEM observations: lips amalgamated, their inner region visibly offset and somewhat expanded, form- ing a small sucker-like perioral disc 4.0-4.5 um wide and divided into six triangular sectors by the existence of six radial, interlabial incisures running from the oral aperture to the margin of the disc, labial and cephalic papillae low, but comparatively large and distinct, button-like, with a coarse pore at their center. Amphid fovea cup-like, its opening 6.0—6.5 um wide, occupying the entire diameter of lip region. Cheilostom 6.0-6.5 um long, almost cylin- drical, thin-walled, with circumoral sclerotized pieces at its anterior end. Odontostyle typical dorylaimid but small, almost equal (0.9-1.0 times) to lip region diameter long, occupying 0.56—0.66% of body length, ca 5.0 times as long as wide, with short aperture ca one-fifth of its length. Guiding ring simple, often inconspicuous. Odontophore visibly flanged, 1.8—2.0 times the odontostyle. Pharynx consisting of a slender and weakly muscular anterior re- gion suddenly enlarging into the basal expansion 10-16 times as long as wide, 5.3—8.1 times longer than body di- ameter at neck base, occupying more than half (53-59%) of the total neck length, and surrounded by a distinct spi- ral muscular sheath, its gland nuclei and outlets obscure in the specimens examined, some specimens bearing a few refractive globules at its anterior end. Cardia small and rounded, 9-11 um long. Female. Genital system diovarian, with both branches equally and variably developed, the anterior 74—122 um or 8—12% of the total body length, the posterior 87-108 um or 9-11%. Ovaries comparatively small, often not reaching the oviduct-uterus junction, 31—61 um the anterior and 36— 48 um the posterior, with oocytes first arranged in two or more rows and then in one single one. Oviduct 42-65 um or 2.1—3.3 body diameters long, consisting of a long and slender distal region made of prismatic cells and a devel- oped proximal pars dilatata with visible lumen. A distinct sphincter present between oviduct and uterus. Uterus a simple tube-like structure 27-38 um or 1.4—1.9 body di- ameters long. Vagina extending inwards 8.0-9.5 um, to less than one-half (38-45%) of body diameter: pars proxi- malis 5.0-6.0 x 6.0-6.5, with almost straight to somewhat convergent walls that are encircled by weak musculature, pars distalis 3.0 um long. Vulva a longitudinal slit ca 2 um long. Prerectum 6.2—6.6, rectum 1.2—1.3 anal body diam- eters long. Tail convex conoid to slightly subcylindrical. zse.pensoft.net 574 Garcia-Ruiz, M. et al.: Retrieval of Capitellus and description of C. caramborum from Spain Figure 1. Capitellus caramborum sp. nov. A-H, J. Female; I, K-M. Male; A. Entire; B. Anterior region, lateral median view; C. Pharyngeal expansion with globules; D. Pharyngeal expansion without globules; E. Neck region; F. Anterior genital branch; G. Anterior region, lateral surface view; H, K. Caudal region; I. Posterior body region with ventromedian supplements; L. Lateral guiding piece; M. Spicule. Scale bars: 200 um (A); 5 um (B, G, J, L); 50 um (C—E); 25 um (F, I; 10 um (H, K, M). Male. Genital system diorchic, with opposite testes. In addition to the adcloacal pair, situated at 4-5 um from the cloacal aperture, there invariably are four very simple (non-mammiform but a low pore-like structure, Fig. 41) zse.pensoft.net ventromedian supplements arranged in a more posterior pair located at 38-41 um from the ad-cloacal pair and two more anterior and spaced ones at 23—25 um from the pos- terior pair. Spicules dorylaimid, strongly curved ventrad, Zoosyst. Evol. 101 (2) 2025, 571-581 575 ‘ : Figure 2. Capitellus caramborum sp. nov. (Female, LM). A. Entire; B, C. Anterior body region, lateral median view; D. Anterior gen- ital branch; E. Anterior region, lateral surface view; F. Neck region; G. Pharyngeal expansion with globules; H. Pharyngeal expansion without globules; I. Vagina region; J. Caudal region. Scale bars: 200 um (A); 5 um (B, C, E, 1); 25 um (D); 50 um (F, G, H); 10 um (J). zse.pensoft.net Garcia-Ruiz, M. et al.: Retrieval of Capitellus and description of C. caramborum from Spain Figure 3. A-E. Capitellus caramborum sp. nov. (Male, LM). A. Posterior body region, with arrowheads pointing at ventromedian supplements; B. Caudal region; C. Spicule; D. Lateral guiding piece; E. Sperm cells; F—H. Capitellus neocapitatus (Peralta & Pefia-Santiago, 2000), comb. nov.; F—H. Female tail. Scale bars: 10 um (A, B, F—H); 5 um (C); 2 um (D, E). zse.pensoft.net Zoosyst. Evol. 101 (2) 2025, 571-581 7 at Figure 4. Capitellus caramborum sp. nov. (SEM). A. Lip region, lateral view; B. Lip region, in face view; C. Vulva, ventral view; D, E. Perioral disc, in face view; F. Vulva region, lateral view; G. Female caudal region, subventral view; H. Cloacal aperture and ad-cloacal genital papillae; I. Detail of ventromedian supplement; J. Caudal pores of female tail. Scale bars: 1 um (A, B, D, E, I, J); 2 um (C, F, H); 5 um (G). 3.74.1 times as long as wide and 1.4—1.7 times longer than body diameter: head 3.0—3.5 um long, up to one-sixth (13- 15%) of spicule length, and almost as long as wide; median piece occupying less than one-third (15-31%) of maximum width; ventral hump and hollow very prominent, the for- mer located at 7.5—9.0 um from the anterior end; curvature 127—128°. Lateral guiding piece simple, 6 um long. Tail somewhat less convex conoid than that of female. Antequera population. Females are morphologically identical and morphometrically very similar to those of Diet: the type population, as the ranges of their more relevant measurements and ratios are coincident or widely over- lap. No male found. Molecular characterization. After sequencing and editing, four sequences were obtained for phylogenetic analyses. Two 18S rDNA sequences, 1719 bp in length (acc. PQ877190—PQ877191), showed 98.14% identity to a sequence (AY552969) assigned to Dorylaimellus virgin- ianus Cobb, 1913 (Jairaypuri & Ahmad, 1980) and 97.85%, 97.62%, and 98.02% identity to sequences assigned to D. zse.pensoft.net 578 Garcia-Ruiz, M. et al.: Retrieval of Capitellus and description of C. caramborum from Spain 100 100 18S rONA ua MZ496941 Mananohus truncalus AY297821 Mananctus aquaticus DO4 18791 Ramanamenmis culidivarax 0.02 100 PQ877190 Capitellus caramborum sp. n. PQ877191 Capitelius carambarum sp. n. 400 AY552969 Darvaimelius virgidianus 100 AY 284821 Dorylaimelius montenegncus AYS11968 Darwaimelius parvulus tel AY911972 Dorylaimelivs fenuidens 100 KT 258982 Sejongira bagangshanansis ng EU8380009 Selandira sp. tH 100, AY146482 Selanaira cf apitica 56 100 AY911924 Defanaira cf anitica KT 258983 Sefandira bagangshanensts 100 MG921266 Sefanaira sp. 100 100 MG921265 Belondira sp 100 MF325137 Synoheilaxanchium maid 1 MF325138 Synohelaxonchium naid a7 JX885740 Axanchaldes smoxyensis OG) MG921264 Axonotium sp OO458737 Metaxanchium giennense 100) 00458738 Melaxonchium giennense 100 PP956610 Quaxanctium alearum “al PP956611 Qleaxonctium olearum AY146505 Axonchium gigas 100 78 AY911911 Avanchiunt gigas too AY911910 Axonchium gigas AYS11914 Axonohuin sp. ‘ey OQ%46544 Axonohium sp 31 AY 146506 Avanchium micans AY911913 Axanchtun? cf safitare AY284779 Chrysanema attenuaturtt AJIG6472 Aivfadarviaimus sp. ea 120 KY 942068 Aladaryaimus sp. KY94 2067 Atladoriainus sp KY119448 Atladaniainius sp 100 AY284794 Fudaryainus minulus AY284804 Microgorwaimus miser 56 AY284805 Microdaniaimus modesius im 100 HG797023 Ayssocaipus iuvertutis 100 HQ637471 RAyssacalpus vinciquerae gasp HG 797025 Heterodarus brevidentatus HG797024 Heferadarus margensis 100 EU477379 Hataragarus veletansis HO404367 Enohadeius sardashtensis FJ042952 Enehodelis babakious a HM851184 Erotadalus fongisarcutus AY911988 Enchogelus hHapedarus FJ042953 Enchadelus macradans HG797026 Enchadelus saxitragae AY593946 Pradarvannus as AJS66484 Eudaorwannus carta AY284802 Epidanfarmus lugdunensis AY 284795 Crassalabiun circuitenuin AY283155 Caliionidarus sp 33 AY284788 Pungentus silvestris 74 AY919274 Pungentus pungens AJS66501 Pungenius sp KY881720 Enchadelaides signyesnsts 100) 100 100 AYS93948 Aparcella simplex 94 AY911892 Aparcalaimalius cf capitatus 54 AY911893 Metanarcelaimus conaidus 100 AYS11896 Aparcelaimeltus abscuraides MK796433 Aporcefaimalus abtusicaudatus oq OP048823 Aparcelaimaius oblusicaudatus OM269524 Aparcelaimalius oablusicaudatus 0141212 Aparcelaimeius abiusicaudatus MN605663 Aparcelaimelius nigeriensis AY284801 Avadandaimus anarassyt AY911895 Apoarcelaimeltus Arygert AY2?84812 Aporcelaimelius cf paraabtusicaudatus 100 MG921244 Calcandaniainus sp AJIB6490 Mesodoniainus ch nigriuus 35 AJ966489 Mesodorylainus japonicus 90 82 TOO 100 KF? 17497 Caicaridarvaimus castaneae LC457654 Calearidaniaimus signatus 100 KY119890 Ecumenicus manahysiera AY284783 Eoumenicus manohystera KMO92519 4Amdlydarniaimus isakarvan 100 GU446710 Paractinolaimus decraemerae 100) AY284826 Paractinalgimus macralaimus id Hh AYOO3978 Paractinalaimus macralaimus GU178030 Paractinalaunus sahana AY 284776 Doryiainus stagnalis 108 EF207251 Oxyairus nethus 100 AYS93949 Oxyarus nethus 56 AY284825 Oxyairus ax yoephalus 100 AY284624 Oxvalrus axycaphalus AY284777 Dorviaimus stagnalis gop 100 AY284785 Syiphodariaimus syiphaides Eel AY284823 Oxyoirus axyoeohataidas EF207248 Masadarwaimus ceniracercus 100 AY 284809 Paraxanchiumn laetificans 100) 37) OQ920987 Pararanchum caimenae 1G AY284830 Darvlaimoides micaleizkyi 100 KU662325 Darviatmardes sp AY593950 Dorwaimaides tinnaphtus 10g MT 645227 Talanema baarii 100 MT645226 Talanema bagi OP?93643 falanema ibenoum en OPT93644 Talanema ibencunt 1 oo] OP793645 Talanema ibericun AY284807 Labronama vulvapapivalunt 100 MK894247 Lahranama moantanunt MK894248 Labranema mantanum 100 KJ636342? Aguatides aquaticus AY552963 Aquaiides christes ue ANY593944 Clavicaudaides clavicaudatus TU) AY552976 Paravulvus hartingtt AY552974 Nygalainus cf parvus 100 Figure 5. Bayesian inference tree from the newly sequenced Capitellus caramborum sp. nov. based on sequences of the 18S rDNA region. Bayesian posterior probabilities (%) are given for each clade. The scale bar shows the number of substitutions per site. montenegricus Andrassy, 1959 (Jairajpuri & Ahmad, 1980), D. parvulus Thorne, 1939 (Jairajpuri & Ahmad, 1980), and D. tenuidens Thorne, 1939, respectively (AY284821, AY911968, and AY911972). Two 28S rDNA sequences, 793 bp in length (acc. PQ877192—PQ877193), showed 83.61% identity to two sequences (KT258984, KT25985) assigned to Belond- zse.pensoft.net ira bagongshanensis Wu, Huang, Xie, Wang & Xu, 2017, 91.14% to those of Belondira sp. (MG921267, MG921268), and 80.71% identity to B. coomansi Gol- hasan, Heydari, Miraeiz, Abolafia & Pefia-Santiago, 2018 (MF363124). Diagnosis. The new species is characterized by its 0.82—1.09 mm long body, lip region offset by constric- Zoosyst. Evol. 101 (2) 2025, 571-581 100 100 100 285 rDNA 100 EF417153 Ramanamermis cultelverax 100 80 100 80 69 92 100 51 65 62 51 g2 100 100 100 100 100 96 3a) 100 100 100 100 100 100 100 700 100 100 99 wo 100 96 100 100 a5 100 99 100 519 PQ877192 Capitellus caramborum sp. n. PQ877193 Capitellus caramborum sp. n. KT258984 Selanaira bagangshanansis KT258985 Selfandira bagangshanensis 1o0 MG921267 Gefandira sp MG921268 Selandira sp MF 363124 Selanaire coamansi PP256616 Oleavanohum aleaanun PPQ56617 Oleaxanchun afeanun 0Q473054 Melaxoncium gannense 0Q473053 Melaxoncium ganrense OQ099690 Melexanchium magnum OQ099692 Meiaxonchium magnum 100) MGO18 767 Metaxanchium taraense MGO018768 Metaxanoiun foraense MH167248 Maelaxonchium stenaspicuwum MH16 7347 Melaxonchium stenaspicuwium JX885739 Avanchaides smoakyensis MF325350 Synoheilaxanchiunt nalit MF325351 Syrohetacanchiunt nat MGS21270 Avanchium sp MGS21271 Axonchium sp 100 100 MG921305 Twenciofaimus ibericus KU9982905 Tywenchalaimus helanensis AY593027 Tylencholeimus mirabilis F207243 Twenchalaimus cf teras KX151719 Anarceila charidamiansis KX151720 Aporcalla chandemiensis JQ778274 Aparceila simplex MH727512 Aparcella simplex MN262455 Aparcella simplex JO778273 Aparcelia simplex 100 100 100 AYS93023 Carofaradisous hanaticus AY593024 Carcharodiscus Banalious EF207238 Discalaimaidas syrmeticous MT?76559 Ofscalaimajiges symmeiricus 56, AY593025 Discalaimus mafar EF207239 Ofscalanmus cf major A¥593026 Discolaimus major MT? 76558 Discolaimus majar KY750844 Discalaimus sp 100 100 100 AY593035 Spidarviainus tugaunensis AY593036 Epiganvaimus lugdunensis AYS93037 Evudaniainus sp AYS93049 Micradarviainius maodestus 100 AY593042 Longidorella ch macramphis HM235515 Longidarevia penetrans AS93045 Langidareva sp AY593046 Micradaniainus miser AY593047 Evdandaimus minulus AY593048 Evaarvaimus minulus MH346474 Pungentus engadinensis AY593053 Pungentus silvesirs 100 gg 100 100 100 100 100 100 100 a? J0927438 Metaporcelaimus capitatus J0927440 Mefaooroeeimus avagranulosus AY593031 Secionema barbatoides KU589226 Sectanema ciiatum 100 66 AY593018 Avorcelaimelius abtusicauaatus JK094340 Apoarcelaimelus abiusicaudatus Jk42 8789 Ap arcelainellus waenga KM406917 Aporcelaimellus pycnus MKO007553 Aparcelinus ftaidensis MH619735 Aparcelinus amazanicus MK007552? Aparcelinus paalae 76 MF 134400 Aporcalinus jigananensis MH619727 Aparcelinus eiongicauaaius MH619728 Aparcelinus insularts 66 AY593016 Afodaniainus anarassyt AY593015 Alodandainus anarassyt aS MKO007554 AVladanaimus sp MH727518 Aparcelnus maditeiranaus 100 100 6g 100 g2 92 100 100 100 100 KY492387 Makatinus crassitaanis KY492387 Makatinus macrostywius KY¥492386 Maxatinus crassifornnis 100 100 100 91 100 56 98 100) 00920984 Paraxonchim canmenae AY593001 Paraxanchiunt /aetificans AY593002 Paraxanchiunt jaetiicarns MHO004441 Cressa/atiun? costaricense MHO004440 Crassolabium castancense AY593004 Donfanmaides micaleizkyt AY593003 Dondaimaides imnaphtus MK894246 Lahronema mantanunt MK 894 244 ¢ abranema mantanumn AY592906 Labronema vulvapapilatun AY5929097 Labronama vulvapapitaltan JN242245 Nevaganema nevadense EF 207241 Prodorylaimus sp GU4467 11 Paractinalaimus decraemerae AY592998 Paractindiaimus macralarnius KM067903 Paractinalainus maus GU178031 Paractinalaimus sahara 100 ON133539 Westindicus sp 55 AY592994 Darvaimus siagnalis 100 AY593005 Mesadanlaimus sp 30 AYS93006 Mesagoraimus sp 100 AY593014 Eoumenteus sp AY593013 Fouwnenicus moanahystera AY593011 Oxydirus nethus AY593012 Oxydirus axycephalus KMO092520 Ami/vdondaimus isokaryan AY593029 Chrysanema ailenuatlum MG921241 Aethalamus ratunaicauda AY593061 Nygalainus of brachyurs EF 207234 Clavicaudaides cravicaudatus EF207237 Clavicaudaiges traphurus EF 207236 Cravicaudaides traphurns AY593063 Monranchus tunbridgansis AY593064 Mananchus truncatus 100 100 100 100 100 100 0.06 Figure 6. Bayesian inference tree from the newly sequenced Capitellus caramborum sp. nov. based on sequences of the 28S rDNA region. Bayesian posterior probabilities (%) are given for each clade. The scale bar shows the number of substitutions per site. tion, and 6.0—6.5 um wide with a distinct perioral re- fractive disc 4.0-4.5 um wide, odontostyle 6.0-6.5 um long, odontophore bearing basal flanges and 1.8—2.0 times the odontostyle long, neck 223-296 um long, pha- ryngeal expansion occupying 53-59% of the total neck length, female genital system diovarian, uterus simple and 27-38 um or 1.4—1.9 body diameters long, vulva (V = 53-56) longitudinal, tail convex conoid to subcy- lindrical (24-34 um, c = 31-38, c’ = 1.8-2.1), spicules strongly curved ventrad and 23-25 um long, and four ventromedian supplements. Separation from its relatives. The new species is similar to C. capitatus and D. neocapitatus. It differs from C. capitatus, a mainly pantropical taxon, in its lon- zse.pensoft.net 580 Garcia-Ruiz, M. et al.: Retrieval of Capitellus and description of C. caramborum from Spain ger (0.82—1.09 vs. 0.58—0.65 mm) and slender (a = 44-51 vs. a = 30-37 in females) body, lip region offset by con- striction (vs. almost continuous), larger odontostyle (5.5— 6.5 vs. 4.5 um), comparatively shorter tail (c = 31-38 vs. c = 21-25), and male present (vs. absent). From D. neo- capitatus, a very close taxon, in its narrower lip region (6.0-6.5 vs. 6.5—7.5 um wide, n= 21), longer odontostyle (6.0-6.5 vs. 5.0-5.5 um) — it means that the odontostyle is almost equal vs. appreciably shorter than lip region di- ameter —, relatively shorter pharyngeal expansion (53-59 vs. 59-63% of the total neck length), more conoid (vs. more subcylindrical, Fig. 3F—H), and comparatively lon- ger female tail (c’ = 1.8—2.1 vs. c’ = 1.3-1.7), and male present (vs. absent). Type locality and habitat. Southern peninsular Spain, the Andalusia region, Cordoba province, Baena munici- pality, “El Valle” farm (37.799704, -4.310439, elevation 351 m), where the new species was found in the rhizo- sphere of an olive grove. Other locality and habitat. Southern peninsular Spain, the Andalusia region, Malaga province, Antequera municipality, “La Capilla” farm (37.198283, -4.543868, elevation 491 m), where the new species was found in the rhizosphere of an olive grove. Etymology. The specific name refers to the “Caram- bos,” the familiar nickname of the first author’s mother. General discussion Morphologically, C. caramborum sp. nov. forms a recog- nizable group of species together with C. capitatus and D. neocapitatus, all of them easily distinguishable by having a distinct perioral disc visibly refractive, which should be regarded as a very relevant synapomorphy (if not autapo- morphy) in Dorylaimellinae. Besides, the general mor- phology of the three species is nearly identical, and their morphometrics (Table 1) are rather similar too. Unfortunately, molecular studies of Dorylaimelli- nae representatives for comparison are limited to a few 18S-rDNA and no 28S-rDNA sequences. Thus, the evo- lutionary relationships of the new species as derived from the analyses whose results are presented in trees of Fig. 5 (18S-rDNA) & 6 (28S-rDNA) only confirm its belong- ing to maximally supported (100%) clades constituted by members of Belondiridae Thorne, 1939 (highlighted in green in both trees), excepting Oxydirus Thorne, 1939 sequences. Nevertheless, this clade includes all Belond- iridae representatives in the 18S tree, while the 28S tree only contains Be/ondira sequences. Present findings support the idea that Capitellus 1s a valid taxon. On the one hand, the new species now described is the third one displaying a very unusual (?unique) feature within Dorylaimellinae, and it forms a recognizable group with two previously known forms. On the other hand, the 18S tree shows that the two se- quences of the new species form a clade that 1s separated from that including other Dorylaimellus species, which form part of another clade together with several belond- zse.pensoft.net irid taxa. Thus, Capitellus is provisionally recovered as a valid genus, and, consequently, D. neocapitatus 1s transferred to it. Updated taxonomy of Capitellus Diagnosis Small-sized nematodes, 0.58—1.09 mm long. Cuticle dor- ylaimid. Lip region continuous with the adjoining body or offset by weak constriction, with fused lips displaying a con- spicuous, perioral, refractive disc. Amphid fovea cup-like, with large aperture. Cheilostom with variably perceptible perioral sclerotized pieces. Odontostyle dorylaimid, up to as long as lip region diameter. Guiding ring simple. Odonto- phore bearing flanged base. Pharyngeal expansion occupy- ing one-half to two-thirds of the total neck length. Female genital system di-ovarian, with longitudinal vulva. Female tail conoid to subcylindrical. Spicules dorylaimid. Four vari- ably spaced ventromedian supplements with hiatus. Type species: C. capitatus (Siddiqi, 1964) Siddiqi, 1983 = Dorylaimellus capitatus Siddiqi, 1964 = Dorylaimellus (Dorylaimellus) capitatus Siddiqi, 1964 (Jairajpuri & Ahmad, 1980) = Dorylaimellus (Capitellus) capitatus Siddiqi, 1964 (Jairajpuri & Ahmad, 1992) Other species: C. caramborum sp. nov. C. neocapitatus (Peralta & Pefia-Santiago, 2000), comb. nov. = Dorylaimellus neocapitatus Peralta & Pefia-Santiago, 2000 Acknowledgements This contribution derives from the project Soil O-Live. 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