Diguetinus spinulatus ( Banks, 1898 )

Jesús, Daniel Ochoa-Vázquez, Cruz-López, Jesús A., Elizabeth, Rogelio Rosas-Valdez & Martínez-Salazar, Elizabeth A., 2025, Redefining the Mexican genus Diguetinus Roewer, 1912 (Opiliones, Phalangioidea, Globipedidae) based on morphology and molecular phylogenetic data, with the redescription of Diguetinus spinulatus (Banks, 1898) stat. restit., Zoosystema 47 (30), pp. 731-749 : 734-744

Diguetinus spinulatus ( Banks, 1898) stat. restit.

( Figs 1 C-E; 2C-D; 3C-D; 4-5; 6G-L; 7D-F)

Leptobunus spinulatus Banks, 1898: 182 .

Hadrobunus spinulatus – Roewer 1910: 254, 257; 1923: 920.

Diguetinus spinulatus – Goodnight & Goodnight 1942b: 11.

Metopilio spinulatus – Cokendolpher 1984b: 376.

TYPE DATA. — Holotype (examined by photographs). Mexico • ♀; Nayarit: Tepic ; 21°30’34.2”N, 104°53’44.5”W (error radius: 8832 m); Banks leg.; MCZ: IZ:14818.

MATERIAL EXAMINED. — Mexico • 1♂, 10 ♀; Nayarit: Tepic: Cerro de la Cruz ; 21°32’4.5“N, 104°53’5.3”W; 1091 m a.s.l.; 28.X.2023; D. Ochoa-Vázquez, O. I. Ochoa-Vázquez leg.; GenBank accession numbers: PV430728-32; CRLSM-OP _02; CNAN-OP2022 .

DIAGNOSIS. — Diguetinus spinulatus stat. restit. can be distinguished from D. raptator by the combination of the following characters: a) leg femur bicolored, first 1/4 of all femurs light yellow-brown, more evident in femur II; b) transverse rows of spines across each tergite of the opisthosoma, with one linear row configuration per tergite; c) alae and glans penis sections similar in length ( c. 1 mm), each proportion 1/8 of the total length of the penis; d) alae section internal texture with a reticulate pattern, dark in colour, present only on apical margin.

REDESCRIPTION

Body leathery in texture, with a tuberculate-microgranulate cuticle morphology (with rounded or pointed protuberances surrounded by small obtuse to acute granules). Dorsum length 10.33 mm (male) and an average length of 11.59 mm ± 0.61 (females: ranging from 10.68 to 12.3 mm). Male dorsum light yellow-brown tone (alcohol preserved), dorsally with black patches on the cephalothorax across each opisthosomal tergite ( Fig. 2C), female dorsum coloration dark-brown tone ( Fig. 1C; 3C). Leg coloration with a gradual transition from light yellow-brown at the base of femurs to brown (male) and dark-brown (female) at patella and tibia, with tarsi and meta-

105° O 104° O tarsus predominantly yellow-brown tones and last metatarsus a gradual dark-brown hue; leg femur distinctively bicolored, at least the first 1/4 portion of all femurs light yellow-brown in color, more evident in femur II. These colorations paler in living organisms ( Fig. 1C). Body cuticle granular, with small spines present on the anterior propeltidium, mesopeltidium, metalpentidium, and dorsal scutum. Spines yellowish-white tipped with black, with at least one chaetal sensilla present near the base of each spine, none of which extended to a height greater than ocularium.

Cephalothorax ( Fig. 2C; 3C; 4) smaller in size relative to the abdomen, particularly in females. Anterior propeltidium with a transverse multiple spined ovoid-shaped area (APH: anterior propeltidium hump). APH gradually raised, wider than long and occupying approximately one-third of the anterior edge of the propeltidium, covered with small black tipped yellowish-white spines, none extended to a height greater than the ocularium ( Fig. 4). Marked cuticular depression on either side of the APH area, running to the posterior part of ozopore. In dorsal view, ocularium round in shape, with a diameter of c. 0. 62 mm (male), c. 0.60 mm (female), about half that distance in height, and approximately its length from the anterior margin of cephalothorax. A lightyellow longitudinal line running through the middle part of the ocularium, dorsally with four to six black tipped yellowish-white spines over each eye. Ozopores elongate across the edge of the cephalothorax, close proximity to the bases of leg I, clearly visible in dorsal view. With small yellowish black-tipped spines (one near the anterior margin of the ozopore and one near the posterior margin). Cheliceral lamellae short and smooth, slightly visible in dorsal view, contiguous with anterior propeltidium edge. Mesopeltidium (posterior to the ocularium) and metapeltidium (final segment of the cephalothotax) each with a single row of a small black-tipped yellowish-white spines; one group of mesopeltidium spines situated within a triangle-shaped area (delineated by a darker colour), where a row of seven to eight spines forms the base of the area when observed in dorsal view ( Fig. 4).

Chelicerae light yellow-brown and black tips chelal fingers. Second segment of each chelicera bearing loose cluster of sensilla chaetica near the base of the fixed digits and an arrangement of five-six slit sensilla, located just before the moveable finger. Basal segment ventrally with a short, smooth bulge.

Pedipalps clamp-like, with a smooth palpal claw that bears a small pointed conical basal denticle. Sexual dimorphism evident in the palpal tarsus, which in males bears a belt of denticles that is absent in females and juveniles. Dorsal surface of each pedipalp patella, with two pale yellow longitudinal lines running from the anterior to the posterior edges, with small dark pointed spines. These particularly noticeable in females, due to the darker coloration of their patellae in comparison with the male revised ( Fig. 2C; 3C).

Leg coxae with evenly distributed sensilla chaetica and small rounded and pointed tubercles facing proxo-ventrally; a distinct row of tubercles present on the distal margin of all coxae, and dark-pointed spines present at least on the posterior-distal margin ( Fig. 2D, 3D). Endites irregularly positioned setae, being more abundant towards the central margin. Neither femur exceeding the total length of the body. Tibiae II with two pseudosegments on each side. Sexual dimorphism in legs I and III; in males, legs I and III stouter than legs II and IV, primarily tibiae, with rows of spines; the metatarsus I and III ventrally with a row of dark-pointed spines, from 18 (metatarsus I) to 10 (metatarsus III) ( Fig. 5A, B); these characters not present in females. Tibiae round in cross-section, with two accessory spiracles, one near the proximal and one near the apical end.

Abdomen (opisthosoma) arched, especially in females. Each tergite of the opisthosoma with a single transverse row of small spines per tergite (spines similar to those in the anterior propeltidium, mesopeltidium and metapeltidium), none of which are larger than the height of the ocularium ( Figs 2C; 3C; 5A).

Male genital apparatus tubular, sclerotized penis and a basal, membranous hematodocha, accompanied by a dorsoventral pair of prominent stiffening rods. Penis ( Fig. 6 G-L) truncus sclerotized, long and slender, with a section of a subterminal lateral alae curved ventrally, this section approximately 1/8 of the total length of the penis. Alae internal texture with a reticulate pattern, dark in colour, present only at apical section, limited to the midpoint of the structure ( Fig. 6J). Glans slightly inclined relative to the axis of the truncus, length similar to alae section ( 0.90 mm glans and 1.07 mm alae section), proportion approximately 1/8 of the total length of the penis. Stylus ( Fig. 6H, J, L) mobile, broad medially, and thickened at the base, inserted dorso-apically on the glans. Surface predominantly dark brown, no evident rugose (wrinkled)

A Leg III B Leg I C

appearance, with a thin distal end, a coiled loop extending a full circumference in a helicoidal form. Total length of the penis, including the stylus length, 8.4 mm. Ovipositor ( Fig. 7 D-F) dorsoventrally flattened cylinder, comprising more than 20 segments. Distal portion of the ovipositor constituted by a bifurcate three-segmented furca ( Fig. 8E). At the base of the furca, the vagina marking the distal end of the uterus internus. On the distal segment, a rounded projection with a sensory termination inserted distolaterally on either side, with a tuft of sensory setae. Each side of segment II of the furca with a row of five sensilla chaetica, and three to four slit-sensilla. Paired seminal receptacles with a single conduct on each side, located at the level of segments 1-3 after the base of the furca ( Fig. 8F).

Measurements

Male: DL=10.33, DW=5.23, BH=5.16, CL=2.93, CW=5.29, OcL=0.63, OcW=0.65, OcH=0.35, GoL=2.61, GoWn=1.07, GoWb=1.76; Female: data presented minimum-maximum values (average value), DL=10.68 – 12.3 (11.59), DW=6.68 – 7.88 (7.21), BH=6.32 – 7.43 (6.92), CL=2.63 – 3.3 (3.0), CW=4.96 – 5.46 (5.23), OcL=0.59-0.69 (0.61), OcW=0.52- 0.71 (0.62), OcH=0.3-0.37 (0.32), GoL=2.33 – 2.65 (2.53), GoWn=1.04 – 1.33 (1.18), GoWb=1.87 – 2.5 (2.10). Legs and palps measurements see Table 1.

TAXONOMIC NOTES The taxonomic classification of Diguetinus spinulatus stat. restit. has undergone several changes over time. Originally described in Leptubunus spinulatus by Banks (1898). Later, Roewer (1910, 1923) considered L. spinulatus part of the genus Hadrobunus , without having reviewed the type material, only following the taxonomic changes of Leptobunus species to Hadrobunus by Banks (1900) and the observation that L. spinulatus is similar to Leptobunus grande Say, 1821 (now Hadrobunus grandis (Say, 1821) , type species of

Hadrobunus ). Goodnight & Goodnight (1942b) examined the type material of Leptobunus spinulatus Banks, 1898 and concluded that this species does not belong to Leptobunus or Hadrobunus , but rather is a member of the genus Diguetinus and identical to D. raptator . In subsequent publications the authors referred to this species as Diguetinus spinulatus (Banks)

0.10

( Goodnight & Goodnight 1945, 1947). Later, Cokendolpher (1984b) undertook a reexamination of the female holotype of L. spinulatus from Tepic, Nayarit, Mexico, and conducted a comparison with the paratypes of D. raptator from Guadalajara, Jalisco, Mexico, and concluded that these individuals are not conspecific and proposed that L. spinulatus should be classified within the genus Metopilio . Cokendolpher et al. (2021) mentioned that the penis morphology of M. spinulatus is similar to that of Diguetinus , and that they differ only in tuberculation, spination, and the less severely modified leg I. However, none of the aforementioned publications provide a detailed description of the morphology of the examined specimens and no illustrations have been provided of morphological characters in support of the taxonomic changes. Furthermore, the male of L. spinulatus was unknown and the original description of the species did not take into account characters of the genitalia.

PHYLOGENETIC ANALYSIS AND GENETIC DISTANCES

The phylogenetic hypothesis based on the mitochondrial COI region is shown in Figure 8. ML inference indicated that all samples generated (sequences from GDL-JAL and TEP-NAY) constituted a monophyletic group with a high bootstrap value of 100%, corresponding to the Diguetinus sensu lato clade. As the most closely related sequence recovered the sequence of Metopilio sp. from Derkarabetian et al. (2023). This was followed by the sequences corresponding to the outgroups of the family Phalangiidae and Sclerosomatidae .

The sequence of Dalquestia formosa was recovered paraphyletic with respect to the Globipedidae (only Diguetinus + Metopilio ) and Phalangiidae clades. A total of two main subclades were recovered within the Diguetinus s.l. clade, both exhibited a bootstrap value of 100%. The purple subclade grouped the sequences from GDL-JAL (the type locality of D. raptator ), while the green clade includes sequences from TEP-NAY (the type locality of D. spinulatus ) ( Fig. 8).

The genetic differences expressed as pairwise distance between the clades identified in the phylogenetic hypothesis described above ( Table 2) showed that the highest divergence values were observed between the outgroup sequences ( Sclerosomatidae and Phalangiidae ) and the remaining groups (ranging from mean 31.9 to 34.6% and 21.6 to 26.8%, respectively), as well as Dalquestia formosa sequence and the remaining groups (from 26.8 to 32.7), then the Metopilio sp. lineage and the remaining groups (from 20.2 to 34.6% of mean distance). The mean divergence between subclades within the Diguetinus s.l. clade was 6.3% (between the D. spinulatus and D. raptator clades, with percentages ranging from 6.1 to 6.9%). Intraspecific divergence observed in D. raptator were from identical sequences to 0.2%, and within D. spinulatus from identical sequences to 0.04%.