Pseudocellus bifer, Teruel, 2018

Teruel, Rolando, 2018, Two remarkable new species of Pseudocellus Platnick, 1980 (Ricinulei: Ricinoididae) from eastern Cuba, Ecologica Montenegrina 19, pp. 73-88 : 79-87

Pseudocellus bifer sp. n.

Figures 7 –12, 14–15, 17–19. Table I Pseudocellus paradoxus [misidentification: specimens, records and data from Playa Verraco and possibly also from Sigua]: Teruel & Pérez, 2003: 177–181; fig. 4; tabs. I–II. Teruel & Armas, 2008: 29, 31–32; fig. 2; tab. II. Teruel & Schramm, 2014: 79; fig. 6 (top). Teruel, 2015: 149–150, 152; fig. 3.

TYPE DATA. CUBA: SANTIAGO DE CUBA PROVINCE: Santiago de Cuba Municipality: Baconao: Playa Verraco ; under rocks semi-buried in leaf litter; 26/August/2013 ; R. Teruel ; 1♂ holotype , 1♀ paratype ( RTO).

17/September/2002; R . Teruel, Y. Pérez, A. Fong, M. Montoya; 1♀ paratype ( RTO) . 29/September/2003; R . Teruel, B. Lauranzón; 2♀♀ paratypes ( RTO) .

ADDITIONAL MATERIAL EXAMINED (not types). CUBA: SANTIAGO DE CUBA PROVINCE: Santiago de Cuba Municipality: Baconao: Playa Verraco ; under rocks semi-buried in leaf litter ; 15/August/2000; R . Teruel; 1 juvenile ( RTO) . 17/September/2002; R . Teruel, Y. Pérez, A. Fong, M. Montoya; 2 juveniles ( RTO) . 10/November/2002; R . Teruel, Y. Pérez; 1 juvenile ( RTO) . 29/September/2003; R . Teruel, B. Lauranzón; 1 juvenile ( RTO) . 4/May/2006; R . Teruel; 1 juvenile ( RTO). Note: specimens not designated as types because juvenile ricinulids lack most diagnostic characters and different species of Pseudocellus occur in close proximity all along the southern coast of Santiago de Cuba ( R. Teruel, unpublished).

ETYMOLOGY. The selected epithet is a Latin adjective that literally means "double, bearing two". It obviously alludes to the possession of two large apophyses in male leg II tibia, which distinguishes at first this species from all other Cuban ricinulids.

DIAGNOSIS. Adult size moderately large for the genus (male 5.2 mm, females 4.9–5.1 mm). Coloration dark red, uniform, in male darker on carapace and legs II. Entire body and appendages covered with short to minute sedose setae. Body robust: carapace slightly longer than wide (length/width ratio 1.16 in male, 1.08 in females), abdomen elongate-oval (length/width ratio 1.90 in male, 1.73 in females). Appendages not conspicuously attenuate. Leg II long but robust (length/width ratio of femur 2.77 in male, 4.86 in females; of tibia 2.90 in male, 3.57 in females; of basitarsus 6.00 in male, 6.79 in females); femur subcylindrical, conspicuously swollen in male, only slightly in females; tibia highly modified in male (conspicuously swollen, internal surface very concave, armed with two very large, vertically aligned apophyses (prolateral and retrolateral), moderately modified in female (slightly swollen, internal surface moderately concave, armed with the same pair of apophyses as in male, but much smaller); basitarsus denticulate all over. Cucullus, carapace, tergal plates and legs densely and finely granulose, with slightly larger granules scattered. Median plate of tergites XI-XII narrowly trapezoidal to rectangular (XI slightly wider than long, XII longer than wide, XIII much longer than wide), without conspicuous discal dome. Pygidium not notched.

DESCRIPTION (adult male holotype; figs. 7, 9, 11, 14, 15a, 18–19; tab. I). Coloration (fig. 7) dark, deep red, without any discernible patterns, but darker on carapace and legs II and paler on chelicerae. Cuticular granulation and denticulation much darker due to heavier sclerotization; pleural and articular membranes yellowish.

Cucullus (fig. 9; tab. I). Much shorter than wide (length/width ratio 0.79), markedly convex and densely covered with short to minute, curved, translucent sedose setae. Anterior margin weakly bilobed, with a shallow median notch. Tegument densely and finely granulose, with slightly larger granules scattered.

Carapace (fig. 9, 15a; tab. I). Slightly longer than wide (length/width ratio 1.16), convex, densely covered with minute, curved, translucent sedose setae and with a shallow median furrow along anterior two-thirds. Anterior margin almost straight, lateral margins essentially straight and convergent anteriorly, posterior margin convex. Eyespots absent. Tegument densely and finely granulose, with slightly larger granules scattered.

Abdomen (fig. 9, 15a; tab. I). Elongate-oval (length/width ratio 1.90), densely covered with minute, curved, translucent sedose setae and with lateral margins shallowly convex. Median plate of tergites XI–XIII narrowly trapezoidal to rectangular, each with a pair of lateral furrows, with anterior, lateral and posterior margins almost straight; XI slightly wider than long (length/width ratio 0.81), almost flat; XII longer than wide (length/width ratio 1.21), almost flat; XIII much longer than wide (length/width ratio 1.85), almost flat. Tegument densely and finely granulose, with slightly larger granules scattered.

Pygidium (fig. 9; tab. I). Very short and wide, not notched and densely covered with minute, curved, translucent sedose setae. Tegument coriaceous.

Pedipalps (tab. I). Densely covered with minute, curved, translucent sedose setae. Tibia moderately long, thick and shallowly curved inwards; tegument very finely and evenly granulose, ventral surface without denticles. Tarsus long and slender; tegument smooth.

Legs (figs. 7, 11, 14, 15a; tab. I). Slender and densely covered with minute, curved, translucent sedose setae, tegument densely and finely granulose, with slightly larger granules scattered. Leg I moderately long, internal surface of tibia with two long, parallel rows (prolateral and retrolateral) of minute denticles, distal half very concave. Leg II long but robust: femur subcylindrical, subquadrate in cross-section and conspicuously swollen (length/width ratio 2.77); patella very short (length/width ratio 1.87) and strongly bent basally; tibia conspicuously swollen (length/width ratio 2.90), internal surface with basal half inflate and distal two-thirds very concave, with two vertically aligned, very large apophyses (prolateral stronger than retrolateral, both densely covered by coarse granules), followed by irregularly aligned, small, sharp denticles (i.e., this tibial surface forms an elongate cavity where the basitarsus fits when folded, see figure 15a herein); basitarsus long (length/width ratio 6.00), club-shaped, sinuose and with variously-sized denticles all over (larger on prolateral surface). Leg III moderately long, copulatory organ depicted in figures 14. Leg IV moderately long.

FEMALE (paratype; figs. 8, 10, 12, 15b; tab. I). Very similar to male, with the following sexually dimorphic differences: 1) legs II much more slender, with the two apophyses small; 2) legs III lacking copulatory organ.

VARIATION. The four adult female paratypes are all very similar in size, i.e., the maximum body length difference amongst them is smaller than 0.3 mm. This is roughly the same size difference between them and the male holotype, thus, all five adults are assumed to represent a single size-class.

Apart from this, the adult females do not exhibit any substantial differences in relative size, shape and cuticular sculpture of the body and appendages.

Juvenile instars have a pale orange to yellow coloration. The subadult male (tritonymph) already possesses leg II tibia with both prolateral and retrolateral apophyses strong, but much smaller than the adult. Nevertheless, the unmodified leg III (i.e., with the copulatory organ not developed) and the coloration described above both attest to their immaturity.

COMPARISONS. As expected from its geographical occurrence, P. bifer sp. n. clearly belongs in the first group defined by Armas (2017) to accommodate all species from eastern Cuba. The unprecedented possession of a large retrolateral apophysis in male leg II tibia (fig. 7b, 11b–c), makes the new species very easy to recognize from them, which all have it vestigial to entirely absent. Moreover, figure 19 herein shows a good habitus comparison of the adult male of P. bifer sp. n. against those of all other eastern Cuban species.

The same conspicuous character is valid to distinguish P. bifer sp. n. also from the four other species described from western and central Cuba. All of them have the male leg II tibia plain unarmed, i.e., entirely lacking any apophyses.

DISTRIBUTION (fig. 18). This species is confirmed to occur in a single coastal locality of southeastern Santiago de Cuba Province, but there is a potential second record nearby (see below, in Remarks section).

ECOLOGICAL NOTES. This species lives under variously sized (usually large) rocks, semi-buried in the leaf litter of the coastal dry forest on karstic terrain, at the base of limestone cliffs, at a distance of 20–600 m away from the seashore (fig. 17). It is constant but uncommon in the samplings, i.e., individuals are found every time regardless the humidity condition (e.g., dry or rainy season), but in reduced numbers only (three or less). Juveniles are always present, but adults appear only sporadically; specimens of all instars are usually found hanging to the underside of the rocks or hidden inside crevices of the same surface. The holotype male and paratype female from the same date were both found in close proximity under the same rock, as were the two juveniles from September 17, 2002.

The vegetation is largely a xeric scrub (fig. 17a), which in the ravines and less-exposed slopes turns into a microphylous semicaducifolious forest (fig. 17b). It is still relatively well preserved, but it has been cleared by logging and partially replaced by crops (e.g., citrus, tubers and bananas) and pastures in some areas, mainly around villages and beach facilities.

REMARKS. A photograph of the holotype of P. bifer sp. n. still alive, was published by Teruel & Schramm (2014: fig. 6 top) misidentified as P. paradoxus . Moreover, the record of this species from Sigua by Teruel & Armas (2008: 32), most likely belongs to P. bifer sp. n. instead, because the site is only 7 km east of Playa Verraco (fig. 18) and has the same ecological conditions. Unfortunately, such identity cannot be confirmed because the voucher specimens are now missing from IES collection.

General Remarks

With the present addition, the Cuban ricinulid fauna reaches 12 nominal species, all of which are national endemics. Eight of them (67%) occur only in the eastern region of the archipelago, in Camagüey (first record), Las Tunas, Granma, Holguín, Santiago de Cuba and Guantánamo Provinces. Nevertheless, this diversity is still underestimated, i.e., at least one new species from the central region (southern Cienfuegos and Sancti Spíritus Provinces) remains undescribed.

On the other hand, some taxonomic problems remain. For example, P. undatus cannot be regarded as satisfactorily described because of the following reasons. First, the original description ( Armas, 2017) entirely omitted data crucial for its accurate distinction, such as full-body images and measurements of body segments (length and width of cucullus, carapace, abdomen and median plates of tergites XI–XIII). And second, the taxonomic definition of P. paradoxus given therein and thus, all species comparisons derived from it, were not based on the holotype (but on alleged topotypes instead) and actually do not match it, as revealed here by its present examination (see fig. 19 herein).

The present author is currently revising all undetermined populations from the eastern Provinces (fig. 18), in order to clarify their taxonomic identity. These results will be published elsewhere, including the redescriptions of P. cubanicus , P. mayari and P. paradoxus (based upon the already available holotypes and/or topotypes), as well as authenticate new locality records for all species.

Figures

Fig. 7. Pseudocellus bifer sp. n., adult male holotype, full-body views: a) dorsal; b) ventral. Scale bar in millimeters. Fig. 8. Pseudocellus bifer sp. n., adult female paratype, full-body views: a) dorsal; b) ventral. Scale bar in millimeters.