Rhabdopygus puylaerti, Bauer, Christian & Prieto, Carlos E., 2009

Bauer, Christian & Prieto, Carlos E., 2009, Three new Assamiidae (Arachnida: Opiliones) from Cameroon, with a redescription of Chilon robustus and comments on related species, Zootaxa 2059, pp. 1-22 : 18-19

Rhabdopygus puylaerti sp. nov.

Figs 7–8 , 29–35 , 56–59 , table 4

Type. 3 holotype ( MRAC /148199) Kounden ( Cameroon), 5º42’N, 10º40’E (UTM: 32N PM83), F. Puylaert leg., 28.12.1975.

Etymology. The species is dedicated to F. Puylaert, who gathered the material loaned by the MRAC.

Diagnosis. A Rhabdopygus species characterized by paramedian pairs of denticles on free tergites, anal operculum with tubercles, ventral surface of first coxa densely set with tubercles reaching prolateral surface, and fourth coxa with a conspicuous denticle on the retroapical corner.

Description. MALE (holotype): Total body length, 5.84; maximal width, 3.34 (at 2nd area of scutum). Scutum length, 3.94 (carapace/scutum ratio, 0.40).

Coloration ( Figs 7–8 ). Ground colour light yellow. Lateral areas of carapace with two irregular dark lines delimiting a field of pigmentation, an exterior line parallel to lateral border and an interior line pointing posteriad. Lateral margin with a dark line running from lateral vertex above coxa II to area V of scutum. Areas of scutum (with darker points on posterior borders) separated by unpigmented stripes reaching lateral margin. Free tergites with darker pigmentation along row of granules and on third tergite along posterior margin. Ventral surface dark yellow. Legs yellow, without discrete pigmentation.

Carapace ( Figs 29, 31 ). Anterior tubercle system with a very short central protuberance and two protuberances with an additional tubercle on each side; inner lateral protuberance two times longer than outer; small marginal tubercle in left corner and another between and above right lateral protuberances (because of the asymmetry it is not possible to tell whether the outer lateral protuberance is formed by twin tubercles). Anterior margin of carapace with a row of 6–7 granules on each side divided by a smooth central area.

Ocularium low, wider than long (30 % and 35 % of carapace width and length, respectively) and situated at 35 % of carapace length, set with two rows of granules with a small postocular tubercle in each row. Sparse denticles anteriorly and laterally of ocularium in a loose curved row. Sides of carapace angled at level of coxa II; from there a row of granules and denticles reaching area IV of scutum, with a double row in transition area between carapace and scutal area I.

Opisthosomal part of scutum ( Figs 29, 31 ). Widest between areas II and III, regularly and gently convex, areas diffusely limited by broad unpigmented stripes. Area I somewhat narrowed medially, with two denticles on each side. Area II with a posterior paramedian pair of denticles. Area III with a pair of paramedian denticles and a posterior row of denticles. Areas IV and V with central denticle rows, these irregularly spaced in area IV.

Free tergites ( Figs 29, 31–32 ). Free tergites with a row of denticles and a paramedian pair of larger denticles, each increasing in size posteriorly. First paramedian denticles scarcely larger than others of same row, second paramedian denticles with some smaller denticles in between them, and third relatively closer to each other. Armature of third free tergite asymmetrical (left denticle is almost in a median position and has two smaller denticles to the left, the normal condition could thus be a trio of denticles). Anal operculum visible from above, medially pointed and with three rows of denticles, one anterior, one central and one along posterior margin.

Venter ( Figs 30, 32 ). Ventral surface densely set with tubercles. Coxa I crested medially on anterior margin by a row of 7–8 closely spaced, high tubercles; two tubercle rows on ventral surface. Central row, running from a broad tubercle to prolateral distal border of coxa, consisting of several large tubercles and interspersed granules. Back row running near retrolateral border (leaving a smooth posterior stripe) and ending at coxal end. A dense field of large granules covering space between rows. Dorsal surface with a large anterior denticle and a small posterior tubercle. Coxa II with a row of tubercles along median two-thirds of anterior margin and with a central row ending in a group of small tubercles covering distal part of coxa; dorsal surface with a large denticle anteriorly and a posterior tubercle touching coxa III. Coxa III with tubercle rows on anterior and posterior margins, apparently fused with surfaces of adjoining coxae; dorsally with an irregular tubercle touching posterior tubercle of coxa II. Coxosternal complex with few dorsal tubercles on coxa IV transforming ventrally into granules, these sparser medially. Posterior margin with a row of granules laterally split into two rows. Spiracles fully visible and spiracular field completely smooth. Coxa IV with a robust tooth at retrolateral end (best visible in oblique view, Fig. 33 ). Free sternites with rows of small granules, these smaller or absent in median part. Free double sternite with irregular granules and a row of closely spaced granules on posterior margin.

Chelicerae ( Fig. 34 ). Small. Basal segment with sparse dorsal and ventral granules on proximal part and a distad-inclined inflated bulla set with closely spaced granules dorsally and a row of granules along mesodistal margin. Distal segment with sparse granules and sparse long setae.

Pedipalps ( Fig. 35 ). Coxa with a small distodorsal denticle. Trochanter with a large ventral denticle with seta and a small dorsal denticle. Femur with a ventral row of 11–12 irregular denticles along three-fourth of femur length, a dorsal row of granules and a sparse distomesal row of granules. Patella and tibia with dense dorsal granulation; patella with two tubercles on distomesal edge and tibia with four granules and two spines on mesal edge (iIiiIi) and three granules and one spine on ectal edge (iiIi). Tarsus with a row of granules, with two spines in each, along ventral edges.

Legs (measurements of palp and legs, see table 4). Covered by fine granules carrying short setae, these nearly inconspicuous on metatarsi. Calcaneus I 9 % of metatarsus length. Trochanter I with two prolaterodistal tubercles. Tarsal formula: 6 (2) / 11–10 (3) / 7 / 7.

Penis ( Figs 56–59 ). Total length, 2.2. Stalk broadened for two-thirds of its length, with a pentagonal penis head (ventral plate), both separated by a slender neck. Base of ventral plate clearly marked. Lateral sides somewhat divergent, with five pairs of ventrally curved setae in basal half, distal half completely smooth. Distal margin forming an obtuse angle with a central notch. Dorsal side of head with a voluminous complex glans ending in a process with an apical knob. Three pairs of tiny additional setae present: Disto-ventral pair Remarks. Rhabdopygus puylaerti sp. nov. has been compared with regard to penial morphology with two nominal species of Rhabdopygus . Rhabdopygus fuscus Roewer, 1912 , the type species, is clearly congeneric because both species have the same penial morphology: Ventral plate longer than wide, five pairs of lateral setae in proximal half of ventral plate, vestigial setae on disto-lateral lobes, glans with the same configuration in lateral and dorsal views ( Figs 60–63 ). The penis of Rhabdopygus maculatus Roewer, 1935 , on the other hand, is completely different: Ventral plate heart-shaped and three pairs of setae situated on widest part of ventral plate ( Figs 64–67 ). With the current level of knowledge it is difficult to establish relationships, but the penis of Rhabdopygus maculatus Roewer, 1935 suggests a close relationship with erecine genera.

Figures

FIGURES 1 – 8. Dorsal (left) and ventral (right) views of males. 1 – 2, Chilon robustus Sørensen, 1896. 3 – 4, Ereca treses sp. nov. 5 – 6, Bueana vitteli sp. nov. 7 – 8. Rhabdopygus puylaerti sp. nov.

FIGURES 29 – 35. External morphology of Rhabdopygus puylaerti sp. nov. (male holotype). 29, body, dorsal view. 30, body, ventral view. 31, body, lateral view. 32, body, posterior view. 33, left coxa IV, dorsolateral view. 34, right chelicera, ectal view. 35, right pedipalp, mesal view. Scale bars: 1 mm.

FIGURES 56 – 67. Penises of Rhabdopygus spp., penis head in ventral (56, 60, 64), lateral (57, 61, 65) and dorsal view (58, 62, 66), and total penis in dorsal view (59, 63, 67). 56 – 59, Rhabdopygus puylaerti sp. nov. (holotype, MRAC / 148199). 60 – 63. Rhabdopygus fuscus Roewer, 1912 (cotype, SSibange, Gabon, SMF / RI – 387). 64 – 67. Rhabdopygus? maculatus Roewer, 1935 (syntype, Lossida Berge, SMF / RII – 5052). Scale bars: Left 0.1 mm, right 1 mm.