Acrobeloides maximus-group

3.2. Species belonging to the Acrobeloides maximus-group

3.2.1. Acrobeloides bodenheimeri ( Steiner, 1936) Thorne, 1937

Figs. 5–7 View Fig View Fig View Fig and Table 2.

3.2.1.1. Material examined. Twenty females and twenty males in good state of preservation.

3.2.1.2. Description

3.2.1.2.1. Adult. Small body (0.52–0.69 mm long in females and 0.49–0.68 mm long in males). Habitus sigmoid after fixation or almost straight. Cuticle 1–2 μm thickness, with transverse striations; annuli 2–3 μm wide at midbody. Lateral fields 7–9 μm wide, occupying 20–35 % of midbody diameter, with four alae limited by five longitudinal incisures, extending to the phasmids, appearing only two or three incisures after these. Lip region with three pairs of conoid lips, smooth. Primary axils Ushaped, bearing a seta-like process at each adjacent lip and lacking guard processes. Secondary axils V-shaped, lacking seta-like processes at lip and lacking guard processes. Labial probolae three, rounded with flattened apex. Stoma cephaloboid; cheilostom with rounded rhabdia; gymnostom very short with rhabdia poorly discernible; stegostom muscular with well sclerotized rhabdia. Pharynx cephaloboid; pharyngeal corpus subcylindrical, 3.1–5.4 times isthmus length; isthmus very short; basal bulb almost rounded, bearing well developed valves. Cardia more or less hemispherical. Nerve ring at 73–84 % of neck length, surrounding metacorpus–isthmus junction. Excretory pore at 76–93 % of neck length, at isthmus or basal bulb level. Deirids at 94–104 % of neck length, at basal bulb level.

3.2.1.2.2. Female. Reproductive system monodelphic-prodelphic, located to the left side with respect to the intestine; ovary posteriorly directed, with flexures posterior to vulva; oviduct alveolated; spermatheca well developed, 1.4–2.5 times body diam.; uterus cylindrical, 3.1–5.7 times body diam. long, differentiated in a long distal part with a scarce lumen and thick walls, and a short proximal part with thinner walls and distinct lumen; post-vulval uterine sac well developed, elongate, 1.5–2.2 times the corresponding body diam. long; vagina curved and bent to the right side, 37–52 % of body wide, with anterior and posterior vaginal glands well developed, spheroid; vulva slightly protruding, located subventral displaced laterally to the right side of body. Rectum 0.9–1.7 times anal body width long, with three rectal glands. Tail conoid, with finely rounded or truncate terminus. Phasmids at 41–58 % of tail length.

3.2.1.2.3. Male. Reproductive system monorchid with testis ventrad flexioned anteriorly. Genital papillae eight pairs, three precloacal and five postcloacal: one anterior lateral, one anterior subventral, one posterior subdorsal and two posterior subventral. Spicules with elongate manubrium with rounded terminus, ventrad bent, calamus slightly wider than manubrium, lamina almost straight with angular dorsal hump, ventral velum well developed, and acute tip. Gubernaculum 0.5–0.6 times the spicules length, with manubrium slightly ventrally curved and almost straight corpus. Tail conoid, slightly ventrally curved, with rounded tip. Phasmids located posterior to the lateral papilla.

3.2.1.3. Remarks. This species is observed with a very constant morphology, appearing some variability at female tail tip (finely rounded to widely round). A new character not observed previously is the position of the vulva, displaced laterally to the right side of body. Other species of the maximus -group appear with this condition, as A. longiuterus ( Rashid and Heyns, 1990) Siddiqi et al., 1992 with vulva displaced to the left side (Abolafia and Pena-Santiago ˜, 2017; Shokoohi et al., 2023), while in A. camberenensis ( De Ley et al., 1990) Siddiqi et al., 1992 and A. saeedi Siddiqi et al., 1992 is slightly bent to the right side. This character is unknown in A. maximus ( Thorne, 1925) Thorne, 1937 .

3.2.1.4. Molecular characterisation. Twelve sequences of Acrobeloides bodenheimeri were obtained: nine 18S rDNA sequences having 890 bp (PQ002791, PQ002792), 883 bp (PQ002797), 881 bp (PQ002799), 855 bp (PQ002798), 820 bp (PQ002794), 819 bp (PQ002795, PQ002796) and 816 bp (PQ002793), and three 28S rDNA sequences having 718 bp (PQ002800), 707 bp (PQ002801) and 614 bp (PQ002802). For 18S rDNA, the Spanish sequences of A. bodenheimeri show 100 % similarity in a fragment in common with 823 bp. Compared with other A. bodenheimeri sequences (AF202159, AF202162, AF034391, JF769009, KC509904, KY126434), the Spanish specimens showed 100 % similarity in a segment in common with 816 bp. With respect to the 28S rDNA, the three sequences of A. bodenheimeri show 99.6 % (2 bp difference with MW667571 and MW667573) or 99.8 % similarity (1 bp differences with AF147064 and DQ145625) in a fragment in common with 588 bp.

3.2.1.5. Localities and habitats. Species found in Salinas de Cabo de Gata collected in sand dunes with xeric vegetation: Asparagus horridus L., Arthrocnemum macrostachyum (Moric.) C. Koch , Eryngium maritimum L., Juncus acutus L., L. fragilis (Asso) Pau , Limbarda crithmoides (L.) Dumort., Limonium delicatulum (Girad) Kuntze. , Lotus creticus L., L. intricatum Boiss. , Lygeum spartum (L.) Kunth., Ononis natrix L., Pallenis maritima (L.)

Demanian indices ( de Man, 1880): a = body length/body diameter; b = body length/pharynx length; c = body length/tail length; c ’ = tail length/anal body diameter; V

= (distance from anterior region to vulva/body length) x 100.

Greuter, Phragmites mauritianus Kunth. , Salicornia europea L., Salsola vermiculata L., Salsola kali L., Sarcocornia fruticosa (L.) A. J. Scott, Suaeda vera Forssk. ex J.F.Gmel. , Tamarix canariensis Wild. , Thymelaea hirsuta (L.) Endl., Zygophyllum fabago L.