Cryptocellus chimaera, Botero-Trujillo, Ricardo & Valdez-Mondragón, Alejandro, 2016

Botero-Trujillo, Ricardo & Valdez-Mondragón, Alejandro, 2016, A remarkable new species of the magnus species-group of Cryptocellus (Arachnida, Ricinulei) from Ecuador, with observations on the taxonomy of the New World genera, Zootaxa 4107 (3), pp. 321-337 : 324-330

Cryptocellus chimaera sp. nov.

( Figures 1–26 , 47–48 , 55 )

Type material. Holotype male (adult) ( MEPN 7813): ECUADOR: Esmeraldas, Reserva Ecológica Mache- Chindul, Estación Biológica Bilsa (aprox. 00º19’32’’ to 00º22’48’’ N; 79º45’05’’ to 79º41’00’’ W, 300–750 m), ‘Bosque maduro’, pitfall trap, 16.x.2007, R. Espinosa, coll. (80% ethanol-preserved). The specimen has the opisthosoma detached from the prosoma; left copulatory apparatus was dissected and stored in a microvial with the specimen.

Etymology. Chimaera is the Latin word for ΧίΜαιρα (ancient Greek), which refers to one of the fabulous creatures of Greek mythology whose body was a puzzle of body parts of different animals. It is used here as a noun in apposition, due the display in the new species of morphological features present in relatives of both New World genera.

Diagnosis. Cryptocellus chimaera sp. nov. is unique among species in the magnus group for which males are known in the very incrassate femur of leg II of male ( Figs. 1 , 15 ). The male of C. pseudocellatus has not yet been discovered; however, the female lacks cuticular pits on the cucullus ( Platnick & Shadab 1977: 15) which are present in C. chimaera sp. nov. Large carapacial translucent areas, similar to those of C. chimaera sp. nov., occur within the species-group at least in C. magnus ( Figs. 35–36 ) and C. bordoni (see Salvatierra & Tourinho 2016: figs. 2a, 3a). The area occupied by these structures on the carapace is much larger in the new species ( Fig. 2 ).

Comparisons. Based on the shape of the male copulatory apparatus, Cryptocellus chimaera sp. nov. most closely resembles C. magnus . Apart from the differences referred to above, C. chimaera sp. nov. can be readily recognized from C. magnus in several aspects, including: i) Tegument covered with bristle-like, translucent setae ( Fig. 1 ); ii) cucullus with abundant pronounced surface tubercles on foremost two thirds ( Figs. 2–3 , 4 ); iii) opisthosoma ovate, with median plate of tergite XII clearly wider than long ( Figs. 6, 8 ); iv) basal segment of pygidium with shallow notch on dorsal posterior border ( Fig. 7 ); v) legs I and II with ventral tubercles from femur to metatarsus ( Figs. 14–18 ); vi) leg IV noticeably more slender than leg III, such that the width of femur IV is approximately half that of femur III ( Fig. 1 ); vii) tarsal process of the copulatory apparatus shallowly bifid ( Fig. 26 ), with pronounced pro-ventral median ledge and array of distinct ventral longitudinal keels; L1 lobe shorter than L2 ( Fig. 26 ); viii) accessory piece of the copulatory apparatus with pronounced ventral sub-basal widening ( Fig. 20 ); L ′ lobe subtly curved and thin ( Figs. 23–24 ); apex with spiniform proventral process and without pro- or retrodorsal processes ( Fig. 25 ); retrolateral surface with series of protruding carinae ( Figs. 24–25 ). See the 'comparative diagnosis' section of C. magnus later in this paper for comparison.

Description. Male (holotype).

Coloration: Figs 1–3 . Cucullus, carapace, sternal region and legs II reddish brown; pedipalps, legs I, III, IV, and dorsal surface of opisthosoma reddish; opisthosoma ventrally with a darkened rounded area, covering the central part of sternites XI, XII, and XIII anteriorly. Longitudinal carapacial translucent areas yellow, contrasting with the background color.

Setation: Figs. 1–18 . Body and appendages entirely covered with fine, bristle-like, translucent setae, which are sparse in sternal region.

Carapace: Figs. 1–2 , 47–48 . Trapezoidal in shape, with lateral margins not parallel (narrowing anteriorly); anterior margin straight in dorsal aspect, slightly re-curved in frontal aspect; posterior margin gently re-curved; carapace longer than wide, widest at level between coxae II and III. Longitudinal translucent areas dorsallydirected in the lateral edges of carapace, without well-defined borders, covering between one third and half the length of the lateral margins, from level of coxae I to level between coxae II and III; translucent areas mostly covered with setae as rest of carapace, glabrous regions as narrow areas at the margin of carapace at level of coxae II. Carapace with symmetrical arrangement of tubercle-containing cuticular pits, as follows: about 17 pits along median longitudinal axis (posterior-most three pits larger); posterior margin with about six pits on each side of the midline (lateral two pairs wider); short oblique rows posterior to the translucent areas, each with about eight pits, the anteriormost pit which penetrates into the translucent areas; few additional isolated pits found between the translucent areas and anterior to these. Carapace without any other pronounced depressions. Granules (apart from those of pits) only found in a row along posterior margin.

Cucullus: Fig. 4 . Wider than long, noticeably widest anteriorly; with abundant strong surface tubercles on distal two thirds; with few tubercle-containing cuticular pits and devoid of furrows.

Chelicerae: Fig. 5 . Movable finger twice the length of fixed finger and more robust; movable finger armed with one noticeably large sub-basal tooth and six small teeth progressively decreasing in size; fixed finger with five teeth, basal and distal ones slightly larger than three middle ones.

Sternal region: Fig. 3 . Coxae I meeting tritosternum; coxae II–IV meeting entirely, progressively decreasing in length; II and III sub-rectangular, IV pear-shaped; coxae II with anterior and posterior margins parallel, each forming a straight line perpendicular to the median axis; suture lines of coxae III and IV each about half the length of that of coxae II (coxae II are larger). Cuticle with minute tubercles along coxal margins (more abundant on pedipalp coxae) and without cuticular pits.

Opisthosoma: Figs. 1 , 8–10 . Oblong truncate, longer than wide, widest at level of tergite XII. Median plates of tergites XI–XIII with paired antero-lateral depressions and lateral margins approximately parallel; median plate of tergites XI and XIII approximately as wide as long, that of XII clearly wider than long, that of X slit-like trapezoidal. Central region of tergite XI median plate only slightly elevated; tergite XIII median plate with rear corners pointy, protruding laterally. Dorsal and ventral surfaces with symmetrical arrangement of tuberclecontaining cuticular pits, as follows: tergite XI median plate with eleven along anterior margin, five on posterior margin, four–five on lateral margins; tergite XII median plate with seven on anterior margin, five on posterior margin, four on each lateral margin; tergite XIII median plate with seven on anterior margin, three on each lateral margin. Internal margin of lateral plates of tergites X to XIII with one–two, six–seven, six–seven and five–seven pits, respectively. Lateral margins of ventral surface with a longitudinal row of pits consisting of one on each side of sternite X, six–seven on XI, seven–eight on XII, and ten on each side of XIII. Ventral pits also present on paired antero-lateral depressions of XI–XIII. Outside of the pits, minute tubercles only found on median plate of tergite X. Basal segment of pygidium with shallow notch on dorsal posterior border; ventral border without notch.

Pedipalps: Fig. 13 . Without cuticular pits; with few tubercles on ventral surface of trochanters I and II. Femur dorsally convex, widened in basal half. Tibia longer than femur, with dorsal surface straight, slightly widened ventrally in basal third, and with array of shallow elongated tubercles [='elevated tubercles' of Salvatierra & Tourinho (2016)] on all surfaces in distal half. Movable claw about twice the length of fixed claw and more robust; fixed claw armed with minute teeth, movable claw toothless or feebly serrate (any teeth might have worn down).

Legs: Figs. 1 , 11–12, 14–18 . Without cuticular pits; leg segments with minute, inconspicuous granules in the very basal and distal boundaries facing the neighbouring segments. Leg II noticeably long and widened, especially on femur which very incrassate; other legs decrease in width in the order III, I, IV. Tibia of legs I and II with ventral notch, shallow on tibia I, more pronounced on tibia II. Legs I and II with ventral tubercles on femur, patella (on I only basally), tibia, and metatarsus, sparse and moderate in leg I, more abundant and sharp-tipped in leg II; the larger tubercles, found in femur and tibia of leg II, are mostly arranged in pro- and retroventral rows; legs III and IV devoid of tubercles. Leg I tarsus elevated, dorsally rounded, with claws sheltered in a cavity with disto-ventral opening; leg II distal tarsomere at least three times longer than the preceding tarsomeres, which are small and subequal in size and shape, with claws sheltered in a cavity with elongated ventral opening [like that of Pseudocellus boneti (Bolívar y Pieltain, 1942) see Talarico et al. 2006: fig. 3b]; leg III unmodified two tarsomeres sub-equal, slightly longer than the small tarsomeres of leg II; leg IV tarsomeres similar to those of leg II, except for terminal tarsomere which is at least twice longer than the preceding tarsomeres; terminal tarsomere of legs III and IV with distal dorsal and ventral V-shaped invaginations so the claws are exposed on either aspect. Leg III metatarsus not inflated, moderately excavated, with pro- and retrolateral subapical lobes; lamina cyathiformis longer than high, obtuse. Trochanter IV unmodified.

Copulatory apparatus: Figs. 11–12 , 19–26 . Tarsal process S-shaped on dorsal aspect, with moderate ipsilateral rotation; somewhat canoe-shaped on lateral aspect, with pronounced pro-ventral median ledge and array of distinct ventral longitudinal keels; dorsal pro- and retrolateral margins sinuous; apex shallowly bifid forming pro- (L2) and retrolateral (L1) lobes; L1 lobe rather horn-like, with irregular margins, shorter than L2. Accessory piece massive from base to apex, predominantly straight except for pronounced ventral sub-basal widening; apex with thin, dorsally-curved, retro-ventral hook-like lobe (L ′), and spiniform pro-ventral process; L′′ lobe not differentiated; dorsal aspect of the accessory piece with longitudinal sperm transfer groove ending in distal opening, retrolateral aspect with series of longitudinal carinae, one of which is especially protruding.

Measurements of male (in mm). Body length, excluding pygidium 7.85; cucullus 1.13 long, greatest width 1.80; carapace 2.60 long, 2.33 wide at level between coxae II and III (where widest); opisthosoma 4.33 long (excluding pygidium), 3.07 wide at level of tergite XII (where widest); median plate of tergite XI 1.33 long, 1.60 wide (where widest); median plate of tergite XII 1.13 long, 1.60 wide; median plate of tergite XIII 1.33 long, 1.67 wide; suture line of coxae II 0.57 long, of coxae III 0.31 long; pedipalp femur 1.27 long, greatest depth 0.54; pedipalp tibia 1.87 long, greatest depth 0.26; femur I 1.47 long, greatest width 0.60; femur II 2.93 long, 1.47 greatest width, 1.87 greatest depth; femur III 0.80 width; femur IV 0.47 width.

Female. Unknown.

Distribution. Known only from the type locality in Ecuador ( Fig. 55 ).

Remarks. The type locality of C. chimaera sp. nov. (Bilsa Biological Station) is found in the lowlands west of the Andes, in North Western Ecuador. It is part of the Mache-Chindul Mointains, an area remarkable for its species diversity that has been proposed to be recognized as a Key Biodiversity Area ( Ortega-Andrade et al. 2010).

Cryptocellus chimaera sp. nov., which is probably endemic to a restricted area, is the second ricinuleid species described from Ecuador. The first species was Cryptocellus leleupi Cooreman, 1976 , which Platnick & Paz (1979) regarded as a nomen dubium due that it had been described on the basis of a protonymph, thus lacking all the adult features used for the taxonomy of the group. The type locality of C. leleupi is “Oriente, Rio Negro,” with approximate geographic coordinates 01°24’32’’ S 78°11’28’’ W in the eastern slopes of the Ecuadorian Andes, Tungurahua province. This is, some 200 km SE of the collection locality of C. chimaera sp. nov. and separated by the Andes ( Fig. 55 ). Adult ricinuleids from this area have not been reported; therefore, C. leleupi is better retained as nomen dubium until such material becomes available and allows the recognition of the species. Different locality records of ricinuleids usually yield different species, and the likelihood that the holotypes of C. leleupi and C. chimaera sp. nov., on different sides of the Andes, could be conspecific is negligible.

Figures

FIGURE 55. Map of Northwestern South America, plotting known locality records of Cryptocellus chimaera sp. nov., Cryptocellus magnus Ewing, 1929 and Cryptocellus leleupi Cooreman, 1976 (nomen dubium).

FIGURES 1 – 3. Cryptocellus chimaera sp. nov. Male Holotype (MEPN 7813). 1, Habitus, dorsal view. 2, Carapace, dorsal view. 3, Prosoma, ventral view (sternal region).

FIGURES 4 – 10. Cryptocellus chimaera sp. nov. Male Holotype (MEPN 7813). 4, Cucullus, frontal view. 5, Chelicerae, dorsal view. 6, Opisthosoma, median plate of tergite XII. 7, Opisthosoma, pygidium, posterior view. 8 – 10, Opisthosoma, dorsal, ventral and left lateral views, respectively.

FIGURES 11 – 18. Cryptocellus chimaera sp. nov. Male Holotype (MEPN 7813). 11 – 12, Right leg III, prolateral and retrolateral views, respectively. 13, Left pedipalp tibia, movable (top) and fixed (bottom) claws. 14, Right leg I, tibia, prolateral view. 15, Right leg II, femur, prolateral view. 16 – 17, Right leg II, tibia, prolateral and ventral views, respectively. 18, Right leg II, metatarsus, ventral view. Abbreviations: ac, accessory piece; Lc, lamina cyathiformis; mP, metatarsal process; MT, metatarsus; tP, tarsal process.

FIGURES 19 – 34. Cryptocellus chimaera sp. nov. and Cryptocellus magnus, copulatory structures. 19 – 26, Cryptocellus chimaera sp. nov.. Male Holotype (MEPN 7813), left copulatory apparatus. 19 – 22, Dorsal, prolateral, ventral and retrolateral views, respectively. 23, Detail of distal half, prolateral view. 24, Idem, retrolateral view. 25, Accessory piece, apex, frontal view. 26, Tarsal process, ventro-frontal view. 27 – 33, Cryptocellus magnus Ewing, 1929. Male (AMNH), left copulatory apparatus. 27 – 30, Dorsal, prolateral, ventral and retrolateral views, respectively. 31 – 33, Detail of distal half on prolateral, retrolateral and ventro-frontal views, respectively. 34, Cryptocellus magnus Ewing, 1929. Female from San Pedro de La Sierra (AMNH), spermathecae. Abbreviations: tP, tarsal process; ac, accessory piece (retrolateral carinae indicated by arrowheads); L ′, lobe of ac; L 1 – L 2, lobes of tP; sg, sperm transfer groove; do, distal opening of sg; sp, spiniform process; t, prodorsal tubercle; ml, pro-ventral median ledge; st, spermatheca.

FIGURES 47 – 54. Translucent areas on carapace of males of the two American ricinuleid genera: carapace on dorsal view (left) and detail of area (right). 47 – 48, Cryptocellus chimaera sp. nov. Holotype (MEPN 7813). 49 – 50 Cryptocellus becki Platnick & Shadab, 1977. (MCN- 002). 51 – 52, Pseudocellus pearsei (Chamberlin & Ivie, 1938). (CNAN-Rc 00032). 53 – 54 Pseudocellus chankin Valdez-Mondragón and Francke, 2011. Holotype (CNAN-T 0263).

FIGURES 35 – 40. Cryptocellus magnus Ewing, 1929. Male and female from Villa Leonor (AMNH). 35, Male, carapace, dorsal view. 36, Female, carapace, dorsal view. 37, Male, prosoma, ventral view (sternal region). 38, Male, cucullus, frontal view. 39, Male, opisthosoma, dorsal view. 40, Female opisthosoma, dorsal view.