Ideoblothrus galapagensis, Mahnert, 2014

Mahnert, Volker, 2014, Pseudoscorpions (Arachnida: Pseudoscorpiones) from the Galapagos Islands (Ecuador), Revue suisse de Zoologie 121 (2), pp. 135-210 : 155-159

Ideoblothrus galapagensis sp. n. Figs 30-34

HOLOTYPE: MHNG; 3; Gardner at Floreana: arid zone, litter, 2.V.1992, leg. S. Peck & J. Cook (92-148).

PARATYPES: Gardner at Floreana: MHNG; 13 4T; arid zone, litter, 2.V.1992, leg. S. Peck & J. Cook (92-148).

DIAGNOSIS: Chelicera with rallum of 6 setae, all finely dentate on anterior border, the proximal one distinctly shorter than the others; pedipalps: femur 2.9-3.0 times (length 0.58-0.59 mm), patella 2.1-2.2 times, club 1.4-1.5 times, hand with pedicel 1.6 times, chela with pedicel 2.9 times, without pedicel 2.7 times longer than broad, movable finger 1.1-1.2 times longer than hand with pedicel and 1.4 times longer than hand breadth; fixed finger with 37-38 small cusped teeth, movable finger with 45-47 cusped teeth; trichobothria ist and est at same level, st nearer to t (areoles not touching) than to sb.

ETYMOLOGY: The species name refers to the Galapagos islands.

DESCRIPTION OF ADULTS: Pedipalps and carapace reddish brown, latter lightened in basal part, tergites undivided, brown, I and II narrower. Carapace with a broad, distinct, median transverse furrow, anterior border with a small, rounded epistome; no eyes; 26 setae (4-6-4-6-6). Chaetotaxy of tergites (setae of alternating length): I 6-7, II-V 9, VI-VII 9-10, VIII-IX 9, X 7(2 lateral, 2 submedial tactile setae), XI 7 (4 tactile setae). Manducatory process with 2 setae, pedipalpal coxa itself with 6-8 setae, coxa I 5-7, II 5, III 4-5, IV 5-6; anterior genital operculum (sternite II) with 6-7 setae, genital opening with 3+3 internal setae; sternal chaetotaxy: III 6-8 marginal setae plus 2 suprastigmal setae on each side plus 2 pairs of short discal setae behind medial notch of anterior margin, IV 9-10+2x2, V-XI 12-13/12-13/11-13/11-12/11/10- 11/6 (4 tactile setae).

Chelicera (Fig. 30): 5 long setae on hand, fixed finger with 10 small teeth, movable finger with 6-7 retrorse teeth; galea spine-like, short, barely extending beyond tip of movable finger (except on left chelicera of holotype, where it is long and slightly curved, thus resembling the galea in females of other species!), subgaleal seta distinctly reaching beyond tip of galea, serrula exterior with 28, serrula interior with 23 lamellae; rallum with 6 setae, all finely dentate on anterior border, the proximal one distinctly shorter than others. Pleural membranes striate, anterior to segment I papillostriate.

FIGS 30-34

Ideoblothrus galapagensis sp. n., 3 holotype (unless indicated otherwise). (30) Right chelicera. (31) Left pedipalp. (32) Trichobothrial pattern, marginal teeth enlarged. (33) Trichobothrial pattern of tritonymph. (34) Subterminal seta of tarsus IV. Scale units 0.1 mm.

Pedipalps (Figs 31-32): femur finely granular in medio-basal part, patella finely granular on medial side, hand finely granular on paraxial side and indistinctly so on antiaxial side; trochanter 1.8 times longer than broad, femur 2.9-3.0 times, patella 2.1- 2.2 times, club 1.4-1.5 times, hand with pedicel 1.6 times, chela with pedicel 2.9 times, without pedicel 2.7 times longer than broad, movable finger 1.1-1.2 times longer than hand with pedicel and 1.4 times longer than hand breadth; fixed finger with 37-38 small cusped teeth, movable finger with 45-47 cusped teeth and 1 weakly developed venedens receptor; venom duct very short, present in fixed finger; trichobothrial pattern (Fig. 32): ist and est at same level, st nearer to t (areoles not touching) than to sb, distal half of t distinctly lanceolate.

Leg I: femur 2.2 times, patella 1.8-2.1 times longer than deep, femur 1.1-1.3 times longer than patella, tibia 4.8-5.0 times, basitarsus 2.3-2.5 times, telotarsus 4.9- 5.7 times longer than deep, telotarsus 1.6-1.7 times longer than basitarsus; leg IV: femur+patella 2.8-2.9 times, tibia 4.9-5.1 times, basitarsus 1.9-2.0 times, telotarsus 4.4-4.9 times longer than deep, telotarsus 1.6-1.7 times longer than basitarsus; tibia with one tactile seta near middle, basi- and telotarsus with one basal tactile seta each; arolia undivided, longer than smooth claws, subterminal seta finely dentate (Fig. 34).

MEASUREMENTS of holotype 3 (paratype 3): Total length 2.63 (2.42). Carapace 0.69/0.55 (0.61/0.53). Pedipalps: trochanter 0.32/0.17 (0.32/0.18), femur 0.58/0.20 (0.59/0.20), patella 0.56/0.26 (0.55/0.26), length of pedicel 0.18 (0.19), hand with pedicel 0.54/0.33 (0.53/0.32), length of pedicel 0.07 (0.07), length of movable finger 0.48 (0.45), length of chela with pedicel 0.97 (0.94). Leg I: femur 0.24/0.11 (0.23/0.11), patella 0.22/0.11 (0.18/0.10), tibia 0.31/0.06 (0.29/0.06), basitarsus 0.12/0.05 (0.11/0.05), telotarsus 0.19/0.04 (0.19/0.03); leg IV: femur+patella 0.55/0.19 (0.55/0.19), tibia 0.44/0.09 (0.44/0.09), basitarsus 0.14/0.07 (0.14/0.07), telotarsus 0.22/0.05 (0.23/0.05).

DESCRIPTION OF TRITONYMPH (1 specimen) (Fig. 33): Carapace with indistinct transverse furrow, epistome small, rounded, 26-27 setae (6-7 on posterior border), 1.1 times longer than broad (0.50 mm / 0.47 mm), tergal chaetotaxy: tergite I 6, II-IX 8-9, X-XI 7 (4 tactile setae); manducatory process 2 setae, pedipalpal coxa itself with 6 setae, coxa I-IV 4; sternal chaetotaxy: III 4+2x2 setae, IV 8+2/3, V-X 10-11, XI 6 (4 tactile setae). Chelicera with 5 setae on hand, fixed finger with 11, movable finger with 6 small teeth, serrula exterior 22 lamellae, rallum 5 setae (proximal one shorter), galea long and curved, reaching tip of galea. Pedipalps: femur, patella and hand indistinctly granular, trochanter 1.8 times longer than broad (0.24 mm / 0.13 mm), femur 2.6 times (0.40/0.16), patella 2.0 times (0.38/0.19), length of pedicel 0.12 mm, hand with pedicel 1.4 times (0.37/0.26), chela with pedicel 2.6 times, without pedicel 2.5 times longer than broad, length of movable finger 0.34 mm, of chela with pedicel 0.68 mm. Leg IV (length/depth): femur+patella 2.7 times (0.41/0.15), tibia 3.9 times (0.30/0.08), basitarsus 1.7 times (0.10/0.06), telotarsus 3.5 times (0.16/0.05) longer than deep.

REMARKS: The new species differs by its larger size from I. curazavius ( Curaçao) , I. colombiae Muchmore, 1982 ( Colombia, Magdalena) and I. caecus ( Mahnert, 1979) ( Brazil, Amazonia) (length of femur 0.58-0.59 mm vs. 0.42-0.48 mm, length of chela 0.94-0.97 mm vs. 0.76-0.87 mm). It shares with I. maya ( Chamberlin, 1938) similar pedipalp measurements and proportions (e.g. femur ratio 2.9-3.0 vs. 2.75, length 0.58-0.59 mm vs. 0.56, chela ratio 2.9 vs. 2.7, chela length 0.94-0.97 mm vs. 1.03 mm), but it differs in the trichobothrial pattern (st close to t in galapagensis sp. n. vs. sb-st-t equidistant in maya ; it distinctly distal to ist-est which are nearly at same level in galapagensis sp. n. vs. it-ist distinctly distal to est in maya ); furthermore, the number of teeth on fixed/movable chelal fingers seems to be higher in maya than in galapagensis sp. n. (46/58 vs. 37-38/45-47). Ideoblothrus maya is known only from a cave in Yucatan ( Mexico).

Muchmore (1972) emphasized the structure of the rallum as a taxonomic character useful to indicate affinities between species of the genus Pachychitra Chamberlin, 1938, a genus that he later relegated to the synonymy of Ideoblothrus Balzan, 1892 ( Muchmore, 1982) . Subsequent observations seem to corroborate the value of this character ( Harvey & Edward, 2007), even if accurate observation of number of setae and their structure can be problematic: Wagenaar-Hummelinck (1948) observed “setae of equal length” on the type specimen of I. maya , whereas Muchmore (1972) indicates for this species (source of information not stated) in his key “proximal seta of cheliceral flagellum distinctly shorter than the others”. Chamberlin (1938) indicated the number of setae in the rallum, but not their lengths.

OLPIIDAE

Aphelolpium cayanum Muchmore, 1979

Aphelolpiumcayanum Muchmore, 1979: 201-203, figs 12-20 (typelocality: Florida, Marathon, Vaca Key , Monroe County) .

SPECIMENS STUDIED: Espanola: 39312; 13; Punta Cevallos area, 30 m, screening of Prosopis litter, Prosopis-Lantana, single Bursera , 11.II.1977, leg. W. G. Reeder. – Floreana: RBINS/MHNG; 23 1♀; BlackBeach, Cryptocarpus litter, 24.III.1989, leg. S. Peck (89-149). – 1♀; 1 km S Black Beach, crevice, litter supralittoral, leg. S. Peck (89-157). – 1♀; peninsula south of Black Beach, littoral zone, 5 m, under Cryptocarpus pyriformis , leaf litter in crevice, 21.I.1987, leg. H. Schatz (87-550). – Gardner atEspanola: 39323; 2♀; 20 m, litteroflarge Opuntia , Bursera-Croton-Cordia community, 13.II.1977, leg. W. G. Reeder. – Isabela: 23 1♀; SierraNegra, 800 m, fern-mosslitter, 13.III.1989, leg. S. Peck (89-130). – 1♀; VolcanDarwin, Upper Dry (Psychotria) zone, 1300 m, shrub layer (80% coverage) dominated by Scalesia sp. , Dodonacea viscosa, furthermore a few Zanthoxylum fagara, Macraea laricifolia and Opuntia insularis , partially decayed leaf litter, pieces of wood and soil (lava); 28.III.1988, leg. L. Baert, K. Desender & J.-P. Maelfait (loc. 90), don. H. Schatz (88-962). – SanCristobal: 13; Baquerizo, beach, 2 kmN, littoralzone, litterundersucculents, 11.II. 1989, leg. S. Peck (89-46). – MHNG/RBINS; 43 1♀ 1T; Baquerizo, 10 m, aridzoneFIT, 11.-23.II.1989, leg. S. Peck.

SHORT DESCRIPTION (43 3♀): The specimens correspond well with the original description of the species from Florida Keys , USA. Carapace with 28-34 setae, 6 on anterior and 4 on posterior margin, mostly 2 thin preocular setae on each side; 1.3-1.6 times (3) (♀ 1.2-1.45) longer than broad. Tergite I with 4 setae, II 4 (13 5), III-VIII mostly with 5-6, but up to 8, IX-XI 8-10, those setae finely dentate/forked. Sternites III/IV: tracheal trunks not dilated. Chelicera: serrula exterior 16-18 lamellae, rallum with 2 unequal, dentate blades. Pedipalps smooth, except for some tiny granules on median face of patella, femur 4.0-4.5 times longer than broad, one tactile seta in basal third ( TS =0.23-0.26), patella 3.0-3.3 times, handcordiform, withpedicel 1.3-1.5 (3) (♀ 1.2-1.3) times, chelawithpedicel 3.4-3.6 (3) (♀ 3.0-3.2) timeslongerthanbroad, finger 1.4-1.6 times longer than hand with pedicel, not gaping; fixed finger with 27-31 broad, retrorse teeth, movable finger with 17-22 teeth (distal 7-9 acute, others broad and flattened); lanceolate setae present on fixed finger; a row of about 8 lanceolate setae on movable finger near trichobothrium t. Leg I: femur 3.4-3.6 times longer than deepand 2.0-2.2 timeslongerthanpatella, patella1.7-2.0 timeslongerthandeep, tibia 3.7-4.4 times, basitarsus 4.1-4.5 times, telotarsus 4.4-5.7 timeslongerthandeep, basitarsus 1.2-1.5 timeslongerthantelotarsus; legIV: femur+patella 2.0-2.2 timeslonger thandeep, tibia 4.1-4.7 (3) (♀ 3.8-3.9) times, basitarsus 3.4-4.0 times, telotarsus 4.3-5.3 timeslongerthandeep, basitarsus 1.1-1.3 timeslongerthantelotarsus .

MEASUREMENTS (3♀): Totallength 1.60-1.98. Carapace 0.49-0.55/0.32-0.42. Pedipalps: femur 0.45-0.54/0.11-0.13, patella 0.35-0.45/0.12-0.13, handwithpedicel 0.29-0.37/0.21-0.28, pedicellength 0.05-0.06, fingerlength 0.42-0.56, chelalength withpedicel 0.71-0.93. LegI: femur 0.22-0.26/0.06-0.08, patella 0.10-0.13/0.06-0.08, tibia 0.16-0.19/0.04-0.06, basitarsus 0.14-0.18/0.03-0.04, telotarsus 0.11-0.14/0.02- 0.03; legIV: femur+patella 0.46-0.53/0.21-0.25, tibia 0.28-0.37/0.07-0.09, basitarsus 0.17-0.20/0.05-0.06, telotarsus 0.14-0.18/0.03-0.04.

REMARKS: This species has been recorded from Florida, in “palm and hardwood litter”. On the five Galapagos islands where it occurs, it has been collected in litter of different plants, from the littoral zone up to an altitude of 1300 m, as well as in flight

interception traps, which implies phoretic behaviour and high dispersal possibilities. No differences have been observed between specimens from the five islands.