Serianus galapagoensis Beier, 1978

Mahnert, Volker, 2014, Pseudoscorpions (Arachnida: Pseudoscorpiones) from the Galapagos Islands (Ecuador), Revue suisse de Zoologie 121 (2), pp. 135-210 : 168-171

Serianus galapagoensis Beier, 1978 Fig. 43

Serianus galapagoensis Beier, 1978: 536-538 , fig. 3 (type locality: Santa Fé, Landebucht, Vegetation über dem Strand ).

Serianus pusillimus (not Beier, 1959): Beier, 1978: 536 - misidentification.

SPECIMENS STUDIED: Champion NE Floreana: 1♀ 1P; arid zone, litter sifting, cactus, 22.IV.1992, leg. S. Peck (92-136). – Espanola: 39329; 3♀; “ 100 m Hill”, 90 m, under lava slabs in lava sand, Bursera-Cordia-Prosopis-Lantana assoc., 8.II.1977, leg. W. G. Reeder. – 39303; 13 2♀ 1T; Punta Cevallos camp beach berm, 2 km W of Punta Cevallos, screened from litter of Prosopis and Vallesia, 8.II.1977, leg. W. G. Reeder. – 39325; 13; Punta Cevallos area, radar site, 100 m, screened from old finch nest in dead Prosopia, 9.II.1977, leg. W. G. Reeder. – RBINS; 13; Punto Cevallos, zone côtière, 0-5 m, 3.III.1988, leg. L. Baert, J.-L. Maelfait & K. Desender (B.88/358). – 39300; 13; 3 km from Punta Cevallos, 30 m, single Bursera on rock outcrop, with Lantana and Prosopis, from Bursera litter, 11.II.1977, leg. W. G. Reeder. – 39434; 1♀; 3 km N of Punta Cevallos, 25 m, screening of old finch nest in Opuntia, Lantana, Prosopis , 11.II.1977, leg. W. G. Reeder. – 1♀; Bahia Manzanillo, Prosopis grove behind beach, dung trap, 8.-10.V.1985, leg. S. & J. Peck (85-184). – 1T; same locality, carrion traps, 5.-10.VI.1985, leg. S. & J. Peck (85-185). – 1♀; Bahia Manzanillo, 5 m, arid zone, FIT, 23.IV.-2.V.1992, leg. S. Peck (92-146). – 123 12♀ 3T 4D 3P; Punta Suarez, 10 m, litter under bushes in seabird rookery, 10.VI.1985, leg. S. & J. Peck (85-187). – 2♀ 2P; Punta Suarez, near Blow Hole, littoral zone, under Sesuvium edmonstonei , well decayed leaf litter, dry to moist and salty, 7.IV.1985, leg. H. & I. Schatz (85-350). – 1♀ 1T; Punta Suarez, 30 m, shrub litter, 29.IV.1992, leg. S. Peck (92-144). – 23 2♀; ridge crest, 125 m, tortoise droppings, 30.IV.1992, leg. S. Peck (92-151); – 1♀ 1D; Punta Suarez, 10 m, Cordia-Cryptocarpus litter, 2.V.1992, leg. S. Peck (92-152). – Fernandina: TNSC 39337; 13; W slope, 500 m, above base camp crater, under bark of downed Zanthoxylum in Psychotria shrub; 17.VIII.1977, leg. W. G. Reeder. – MHNG; 2♀; Cabo Hammond, cormorant nests. 29.V.1996, leg. S. Peck (96-208). – Floreana: TNSC 39244; 1♀; Loberia, south of Black Beach, screening litter, 18.II.1979, leg. W. G. Reeder. – RBINS/MHNG; 33 1♀; Black Beach, Cryptocarpus litter, 24.III.1989, leg. S. Peck (89-149). – MHNG; 13 2♀; 1 km S Black Beach, crevice, litter supralittoral, 23.III.1989, leg. S. Peck (89-157). – 1D; Punta Cormoran, 5 m, leaf litter under Waltheria ovata , dry zone, 6.IV.1985, leg. H. & I. Schatz (85- 327). – Gardner at Espanola: TNSC 39315; 13; 20 m, under rocks in shade of Opuntia , Bursera-Croton-Cordia community, litter thin, very dry, 13.II.1977, leg. W. G. Reeder. – 39323; 23 2♀ 1T; 20 m, litter of large Opuntia , Bursera-Croton-Cordia community, 13.II.1977, leg. W. G. Reeder. – RBINS; 2♀; littoral zone between Sesuvium, 24.III.2000, leg. L. Baert, J.-P. Maelfait & K. Desender (B00/059). – 1♀; “summit”, dry zone with Cordia lutea , Croton scouleri , Bursera graveolens, Lantana peduncularis; grass and leaf litter on red soil, sifted, 30 m; 14.III.1987, leg. H. Schatz (87-H294). – Gardner at Floreana: 13 2♀ 1T 2D; arid zone, litter, 2.V.1992, leg. S. Peck (92-148). – Genovesa: 39327; 23; Bahia Darwin, 15 m, screened from litter of Cordia lutea and Croton , also beneath small lava rocks in litter (also Opuntia , Bursera ), 22.XII.1975, leg. W. G. Reeder. – 39333, 39347; 23 3♀; southern rim crater, 65 m, sifting of dry litter of Bursera and Croton , with Lantana, dry rocky substrate, 23.X.1975, leg. W. G. Reeder. – 83 2♀ 1T 1D; Bahia Darwin, 1 m, back-beach, litter washing, 27.III.1992, leg. J. Cook & S. Peck (92-62). – 13; Bahia Darwin, 1 m, arid zone, dung trap, 10-25.III.1992, leg. S. Peck (92-11). – 1♀; inner of island, in Chamaesyce, sifted from dry litter, 14.II.1985, leg. H. & I. Schatz (85-H11). – Isabela: 13; Punta Garcia, W Volcan Darwin, in Aa lava flow at coast awashed spray area, littoral zone, 0 m; in mangrove belt, under Rhizophora mangle; algae from rocks, 21.II.1987, leg. H. Schatz (87-698). – 1♀; Punta Garcia, west of Volcan Darwin, in Aaflow at coast, awashed spray area, 0 m, in mangrove belt, under Laguncularia racemosa, algae from rocks and pumice, 21.II.1987, leg. H. Schatz (87-699). – Marchena: RBINS; 1♀; near fumaroles, 21.II.1974, leg. S. Jacquemart (97). – RBINS; 1♀; Playa Negra, dry arid zone, 21.II.1974, leg. S. Jacquemart (99). – RBINS; 1D; Playa Negra, border of the sea, 25.II.1974, leg. S. Jacquemart (107). – 39305; 43 2♀ 2T; SW slope beach camp area, screening of Waltheria litter, damp, with lava sand substrate, 25.I.1977, leg. W. G. Reeder. – 39296; 23; Cabo Espejo, SW slope above beach camp, removed from damp rotten Bursera wood, Bursera-Croton community, 27.I.1977, leg. W. G. Reeder. – North Plazas: 39318; 2♀; 5 m, sweeping in Maytenus and Castela, Opuntia-Castela-Scutia association, 20.X.1975, leg. W. G. Reeder. – Pinta: RBINS; 2♀; transect to top, dry pampa zone, 25 m, 27.II.1974, leg. S. Jacquemart (109). – RBINS; 13; Eastern transect, Pisonia litter, 27.II.1974, leg. S. Jacquemart (117). – 39335; 13; near South Playa, 20 m, screening of very dry litter of Cordia and Bursera , substrate dry red lava sand, 22.IV.1977, leg. W. G. Reeder. – Pinzon: RBINS; 13; beach with Sesuvium, 20.I.1974, leg. S. Jacquemart (31B; 24965). – 1T; southern slope, Fern Sedge zone, 300 m, under Croton scouleri, Althernathera echinocephala, Prosopis juliflora, Acacia macracnatha, Courmelina diffusa , Pteridium aquilinum ; fern litter and roots with soil, 3.II.1987, leg. H. Schatz (87-601). – San Cristobal: 39367; 1♀; Cerro Felado, 450 m, from litter and moss-fern growth, base of lava blocks, soil well-drained, litter thin, Scalesia-Psychotria-Chiococca-Zanthoxylum comm., 17.II.1978, leg. W. G. Reeder. – 1T; Baquerizo, 10 m, arid zone FIT, 11.-23.II.1989, leg. S. Peck (89-48). – 53 15♀ 1P; Baquerizo, 3 km SE, littoral zone, litter under beach plants, 11.II.1989, leg. S. Peck (89-49). – 13 1♀; Baquerizo, 3 km SE, beachdrift, 12.II.1989, leg. S. Peck (89-54). – 1D; lake El Junco, 670 m, Miconia zone, fern litter under Miconia robinsoniana and Pteridium aquilinum , 28.III.1985, leg. H. & I. Schatz (85-298). – RBINS; 13; Caleta Sapho, Puerto Grande, 2 m, 24.III.2009, leg. L. Baert, F. Hendrickx & W. Dekoninck (B.09/026). – Santa Cruz: 39272; 13 1P; transect from Caseta south to coast, 70 m, Quadrat A-2, 23.VIII.1970, leg. W. G. Reeder. – 39290; 1♀; transect from Caseta south to coast, 70 m, Quadrat A-4, 23.VIII.1970, leg. W. G. Reeder. – 39292; 1♀; transect from Caseta south to coast, 60 m, Quadrat B-3, 23.VIII.1970, leg. W. G. Reeder. – 34100; 2♀ 1D; transect from Caseta south to coast, 60 m, Quadrat B-3, 23.III.1970, leg. W. G. Reeder. – 39285; 1♀; transect from Caseta south to coast, 60 m, Quadrat A-4, 23.VIII.1970, leg. W. G. Reeder. – 34101; 1♀; transect from Caseta south to coast, 40 m, Quadrat A-2, 24.VIII.1970, leg. W. G. Reeder. – 39282; 1♀; transect from Caseta south to coast, 40 m, Quadrat D-3, 24.VIII.1970, leg. W. G. Reeder. – 34098; 13; transect from Caseta south to coast, 30 m, Quadrat C-4, 24.VIII.1970, leg. W. G. Reeder. – 39270; 1T; transect from Caseta south to coast, 30 m, Quadrat D-3, 24.VIII.1970, leg. W. G. Reeder. – 39275; 1♀; transect from Caseta south to coast, 30 m, Quadrat A-4, 24.VIII.1970, leg. W. G. Reeder. – 39288; 1♀ 1T; transect from Caseta south to coast, Quadrat E-2, 24.VIII.1970, leg. W. G. Reeder. – RBINS; 3♀; CerroColorado, 25.V.1975, leg. H. Franz (SA-292). – 1P; near Puntudo, 730 m, underfernsinlitter, 7.II.1985, leg. H. & I. Schatz (85-55). – 1P; CerroCrocker, 860 m, Fern Sedge zone, under Pteridium aquilinum ssp. arachnoideum , fern litter and pieces of wood, 7.II.1985, leg. H. & I. Schatz (85-113). – 13; LosGemelos, 3 kmNSantaRosa, 570 m, Scalesia forestlitter, 13.VI.1985, leg. S. & J. Peck (85-188a). – 13; northside, 1 kmECal. TortugaNegra, soilwashing, upperbeach, 2.IV.1989, leg. S. Peck (89-189). – 1P; PuertoAyora, TortugaBay, brackishlitterundermanchineel, 0.5 m, 29.VI.1991, leg. S. Peck (91-258). – 43 3♀ 3T 1D; south-east, PuntaRocafuerte, aridcoast, Cordia litter, 7.V.1992, leg. S. Peck (92-161). – RBINS; 2♀; CDRS, littoralzone, Sesuvium, 1-2 m, 28.II.1982, leg. L. Baert & J.-P. Maelfait (B28.2.2). – RBINS; 1♀; roadtoItabaca, bush, 23.I.2010, leg. F. Hendrickx & W. Dekoninck (FH10/019). – Santa Fé: 39263; 23 13; 400 m SSW of Camp Bay, 40-50 m, screened from litter of Scalesia helleri and Cordia lutea , blocky talus, base first barranco, 23.I.1979, leg. W. G. Reeder. – 39273; 1♀; rock outcrops of second barranco, 1 km SSW of Camp Bay, 100 m, litter of Cordia and Croton , sheltered but very dry, 24.I.1979, leg. W. G. Reeder. – 39260; 1♀; 1.75 km SSW of Camp Bay, 130 m, from Oryzomys nest of Opuntia fibers underdowned Opuntia trunk, Bursera area, 25.I.1979, leg. W. G. Reeder. – MHNG/RBINS; 13 1D; littoralsoilwashunder Cryptocarpus, 5.IV.1989, leg. S. Peck (89-203). – RBINS; 1♀ 1D; alt. 30 m, Scalesia litter, 5.IV.1989, leg. S. Peck (89-209). – CDRS; 1♀; sectortouristico, bajo rocas, XI.1990, leg. S. Abedrabbo. – Santiago: RBINS; 13 1♀; highland, 800 m, 6.III.1986, leg. L. Baert, J.-P. Maelfait & K. Desender (B086/063). – Seymour: MHNG/RBINS; 1♀ 2T; 15 m, litterunderbushesinfrigatebirdrookery, 23.I.1989, leg. S. Peck (89-18). – RBINS/ MHNG; 13 5T 1D; SWend, litterunderlittoralshrubs, 1 m, 23.I.1989, leg. S. Peck (89-20). – SouthPlazas: 39271; 13; undersurfacelava, 4.III.1970, leg. W. G. Reeder. – 39365; 1T; alt. 2-3 m, under lava stones just above high tide line, below Sesuvium, west end of island, heavy use by sea lions; 28.V.1975, leg. W. G. Reeder. – 39262; 33 3♀; 10-12 m, screening of damp litter under Opuntia pad and rotting Opuntia stump base, 19.III.1975, leg. W. G. Reeder. – 39278; 13; 12-15 m, understonesoflavagravel-sandsubstrate, nolitter, 19.III.1975, leg. W. G. Reeder. – MHNG; 93 3♀ 1T 1D 1P; arid shrubs and succulent litter, 6.V.1992, leg. S. Peck (92-162).

SHORT DESCRIPTION: Chaetotaxy of carapace and tergites as indicated by Beier (1978), without variation. Sternites of 3: VI with 4-6 median glandular setae (more or lessinsemi-circulararrangement), VII 4-5 (semi-circulararrangement), VIII 2-3. Chelicera: rallum with 4 setae, distal one dentate on anterior margin, serrula exterior with 16-18 lamellae (1♀ with 20, only left chelicerae studied). Pedipalps of 3 (♀): femur 2.9-3.2 (2.8-3.4) times, patella 2.2-2.5 (2.1-2.6) times, handwithpedicel 1.8-2.1 (1.7-2.1) times, chelawithpedicel 3.1-3.6 (3.1-3.4) times, withoutpedicel 2.8-3.3 (2.8- 3.1) times longer than broad, finger in 3♀ 1.2-1.4 times longer than hand with pedicel. Fixed finger (3♀) with 24-30 teeth, movable finger (3♀) with 18-23 teeth; venom ducts very short. Trichobothria: st of movable finger normally above sb, in one 3 on left side distinctly distal of sb; trichobothrial pattern of 3, trito- and deutonymph as in Fig. 43 a-d. LegI: telotarsus 1.4-1.8 (frequently 1.5-1.6) timeslongerthanbasitarsus; legIVof 3 (♀): femur+patella 2.4-2.7 (2.6-3.1) times, tibia 3.1-3.6 (2.9-4.0) times, basitarsus 1.6-1.8 (1.6-2.2) times, telotarsus 2.4-2.7 (2.2-3.0) timeslongerthandeep; chaetotaxy of basitarsus: TS+1/1/1 (paired). Arolia divided in distal half, much longer than claws.

MEASUREMENTS of 163 (11♀)(specimens from most of the islands): Total length 2.16-2.84 (2.33-3.98). Carapace 0.53-0.68 (sclerotizedpart)/0.34-0.42 (0.59- 0.82/0.35-0.45). Pedipalps: femur 0.41-0.51/0.14-0.16 (0.48-0.62/0.16-0.20), patella 0.41-0.51/0.18-0.23 (0.48-0.61/0.20-0.26), hand with pedicel 0.44-0.56/0.22-0.29 (0.52-0.67/0.28-0.33), lengthoffinger 0.34-0.43 (0.40-0.47), ofchelawithpedicel 0.77-0.93 (0.89-1.12). LegIV: femur+patella 0.41-0.49/0.16-0.19 (0.47-0.63/0.17- 0.23), tibia 0.29-0.36/0.08-0.11 (0.33-0.43/0.10-0.15), basitarsus 0.09-0.10/0.05-0.06 (0.10-0.14/0.06-0.07), telotarsus 0.12-0.13/0.04-0.05 (0.12-0.16/0.05-0.06).

REMARKS: The specimens from the island of Pinta (NHMW 22819, 13 1♀ examined), identified by Beier (1978) as S. pusillimus , belong without doubt to S. galapagoensis ; Beier's statements on their tergal chaetotaxy (tergite I and II with 4 setae, III-IX with 6 marginal setae) are due to a mistake: chaetotaxy of tergites I-VI of both specimens is 4-4-4-4-4-6. Serianus galapagoensis is one of the most common species on the archipelago, being present on most of the sampled islands. It occurs from the littoral zone up to an altitude of 860 m, in moist to arid habitats, mostly in litter, but was also collected in flying insect traps and in nests of various bird species which probably facilitate its dispersal within the archipelago.

Nymphal stages of Serianus galapagoensis (and other Serianus species) and of the widely distributed Galapagodinus franzi may be differenciated as follows: tritonymphs are separated by presence/absence of trichobothrium est; deutonymphs are clearly separated by the trichobothrial pattern (6+2 trichobothria on chelal fingers in S. galapagoensis , 5+ 1 in G. franzi ), and also in the shape of the galea (apical fork and lateral branch much longer in G. franzi than in S. galapagoensis ); protonymphs can be separated by the shape of the galea.