Neocaeculus orientalis Fuangarworn & Butcher, 2015, sp. nov.
Creators: name: Fuangarworn, Marut
name: Butcher, Buntika Areekul
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Prostigmata
Caeculidae
Neocaeculus
Neocaeculus orientalis

description: Neocaeculus orientalis sp. nov.
(Figs. 1–11)
Diagnosis. Adult female unique among known Neocaeculus in having the following combination of characters: body length 978 – 1164; seta vi absent; trichobothrium sci clavate; anterior margin of prodorsal plate strongly downturned but without projection; lateral eye plates separated from prodorsal plate; dorsal plate P divided; pleural plates absent; seta ve anterior to sce and situated far apart from its pair; seta c1 situated far apart from its pair; unpaired dorsomedian setae present; coxal setation of 5-1-2-1(4a excluded); aggenital plates small with one pair of aggenital setae; one pair adanal setae; palp setation (tibial claw excluded) 0-4-4-5(ω); leg femur I divided but femora II – IV entire; and trichobothrium present on tarsi III – IV.
Description. Female. Body length (including gnathosoma; n = 5) 1038 (978 – 1164); body width (greatest width) 683 (638 – 752). Gnathosoma black in color; sclerotized plates on idiosoma usually black, membranous integument pale cream in color; legs also black except articulations and tarsi being pale cream in color; body and appendages with thick cerotegument.
Gnathosoma. Anterior thirds of gnathosoma visible from above (Figs. 1 – 3). Chelicera typical for family, about 55 wide at base, 210 long (including proximal part of chelicera inserted into body); oriented obliquely about 45° to level of its insertion (Fig. 3 A); movable digit hook-like, with minute teeth; cheliceral seta, cha, slender, 10 – 12 long. Palp (Fig. 3 B) 4-segmented, trochanter short, without setae; femorogenu with 4 clavate setae; tibia with prominent terminal claw set on projecting tubercle, 2 clavate setae and 2 spiniform setae; tarsus subcylindrical, swollen near middle, with recessed solenidion ω, 2 spiniform setae and 3 eupathidia; supracoxal seta ep peg-like. Subcapitulum posteriorly round, anteriorly subconical, 194 (185 – 200) wide at level of palp insertion, 192 (175 – 200) long; with two pairs of slender subcapitular setae: m, 46 (40 – 50) long, n, 40(35 – 50) long, m situated anterior to n; two pairs of short slender adoral setae, or1 – 2, about 14 long. Lateral lips and labrum typical for family (Coineau 1974a). Peritreme linear, segmented, situated on cheliceral shaft (Fig. 3 A, per).
Idiosoma. In dorsal view (Fig. 1), broad ovate, 926 (876 – 1030) long (including naso). Striated integument moderately sclerotized, pattern of striations as illustrated. Nasal plate, subrectangular, 102 (100 – 110) long, 148 wide, well sclerotized. Prodorsal plate subtrapezoidal, 277 (215 – 350) long, posterior margin 293 (275 – 300) wide, anterior margin 153 (140 – 175) wide; lateral margin of plate concave; surface with shallow depressions and low ridges; in lateral view (Fig. 3 A), anterior fourths (ca. from level of sce to ve) of plate downturned to dorsal profile of nasal plate and chelicerae; anterior margin of plate not projected but slightly overhanging posterior margin of nasal plate. All normal prodorsal setae clavate, slightly flattened and barbed; seta vi absent, trichobothrium sci clavate, 107 (90 – 120) long, bothridial opening elevated and situated at posterior corner of nasal plate; seta ve, 59 (50 – 65) long, on anterior corner of prodorsal plate; seta sce, 34 (30 – 35) long, located 74 (60 – 100) posteriad ve; distance from sci–sci 122 (105 – 130), ve–ve 108 (100 – 125), sce–sce 137 (100 – 180); a pair of neotrichous setae (Fig. 1, asterisked) present, 41 (35 – 45) long, near posterior margin of plate. Lateral eye plates separated from prodorsal plate; anterior pair of lateral eyes 40 (35 – 45) diameter, posterior pair 33 (30 – 35) diameter; unpaired median eye, under naso, 26 (25 – 30) diameter.
Opisthosoma with seven dorsal plates: unpaired dorsal plate (D), subrectangular, 285 (260 – 315) long, 273 (250 – 290) wide, with incision on lateral margin; paired lateral plates (L), obliquely flanking plate D, elongate and subrectangular, 350 (300 – 400) long, 108 (75 – 150) wide; paired median plates (M) subrectangular, 63 (50 – 75) long, 175 (150 – 210) wide; and smaller paired posterior plates (P), 47 (35 – 50) long, 134 (115 – 150) wide. All dorsal opisthosomal setae clavate, slightly flattened and barbed; setae c1, d1, e1 on plate D; setae c2, d2, e2 on plate L; setae f1 and f2 on plate M; setae h1 and one lateral seta on plate P; seta h2 located on striated cuticle below plate P; three unpaired median setae present (Fig. 1, asterisked) between f1 – f1, h1 – h1, and h2 – h2, respectively; measurements: c1 50(45 – 55), c2 56(40 – 75), d1 54(45 – 60), d2 51 (35 – 75), e1 70(55 – 85), e2 57(40 – 75), f1 59(50 – 70), f2 60(40 – 80), h1 53(45 – 70), h2 48(40 – 60), ps1 36(25 – 40), ps2 40(35 – 45), ps3 40(35 – 45). Lyrifissures normal (Fig. 1): ia and im on plate L, ip lateral to plate M, ih on ventral side.
In ventral view (Fig. 2), membranous integument striate with pattern as illustrated; coxal plates I–IV normally radial arranged; distal end of coxa I well projected dorsally such that insertion of leg I situated above that of leg II (Fig. 3 A). Coxal setation (I–IV): 5-1-2-1(4a excluded); coxal setae clavate of various length, most setae relatively short but 1c, 1d, 1e much elongate and situated on tubercle which increasing in size from 1c to 1e; broad tubercle (tb) present between base of seta 1e and insertion of leg I; 4a situated on membranous integument; supracoxal seta eI peg-like; measurements of coxal setae: 1a 26(20 – 35), 1b 50(45 – 60), 1c 117(100 – 140), 1d 148(130 – 165), 1e 154(125 – 175), 2a 37(35 – 40), 3a 45(35 – 65), 3b 36(35 – 40), 4a 34(30 – 40), 4b 29(20 – 35). Genital opening (Figs. 2, 4 A) 155(125 – 175) long, genital plate 42(25 – 50) wide, usually with 6 pairs of genital setae (g1–6; 5–7 setae may be asymmetrically present), short, slender, about 15 – 20 long, and arranged in longitudinal row. Aggenital plate small, 95(75 – 100) long, 25 wide, anterolateral to genital plate, with 1 pair of clavate setae (ag). Anal opening 144(125 – 160) long; adanal plate 46(40 – 50) wide, 1 pair of adanal setae (ad) present, clavate, 22(15 – 30) long. Pseudoanal plate 145(125 – 175) long, 31(25 – 40) wide, with 3 pairs of clavate setae (ps1–3); with 11 pairs of setae on membranous integument (4a excluded). Three pairs of genital papillae (Va, Vm, Vp) present, diameter about 15; Vm closer to Vp than Va; associated setae k absent. Ovipositor (Fig. 4 A) roughly plicated; relatively short when protruded, about 95 long; distally with 3 pairs of minute eugenital setae: 2 anterior pairs, and 1 posterior pair on short lobe.
Legs. Measurements (from trochanter to tarsus, pretarsus excluded): leg I 1205 (1030 – 1339), leg II 803(773 – 855), leg III 754(670 – 906), leg IV 848(773 – 948); femur I divided, but femora II–IV entire (Figs. 5 – 6); trichobothrium present on tarsi III–IV; claws on leg I–IV typical for genus; Chaetotaxy of legs I–IV (famuli k and ε included, solenidia in parenthesis): trochanters 6-8-3-4; [basi+telo]femora [8+7]- 15-10-10; genua 19-17-10-9; tibiae 22(1)-21(1)-15(1)-16(1); tarsi 28(1)-27/25(1)-17-17; on tarsus II, v1 ", v2 ' absent in one specimen. Solenidion ω on tarsi I–II, φ on tibia I–IV, seta k on tibia I and seta ε on tarsi I–II recessed; trichobothrium bt on tarsi III–IV slightly dilate and barbed; following setae on leg I hypertrophied, spine-like: trochanter, l', l1'; femur, v', v1 ', v1 "; genu, v', v1 ', v"; and tibia, v', v", v1 ', v1 ". Homology of leg setae and solenidia depicted in Figs. 5 – 6.
Male. Body length (including gnathosoma, n =2) 916(783 – 1050); body width 670(577 – 762); generally similar to female, except aggenital setae more slender (Fig. 9 D) and genitalia present (Fig. 4 B). Genitalia outline with 2 pairs of lateral wing-like extensions; 2 pairs of densely denticulated lobes in middle region; 8 pairs of eugenital setae: setae 1, 2 and 4 large, spine-like and slightly curved, seta 8 spine-like but smaller, setae 3, 5, 6 and 7 minute, distributed as illustrated.
Ontogeny. Larva (n =5): body length 350(325 – 390), width 270(260 – 290); protonymph (n =2): 450, 338(335 – 340); deutonymph (n =3): 573(515 – 608), 415(381 – 433); tritonymph (n =2) 773, 540(515 – 567).
Gnathosoma. similar to female, except lateral lips with 1 pair of adoral setae (or1) in larva, 2 pairs in protonymph (or2 added); palp femorogenu with 2 setae (dF, dG) in larva (Fig. 7 F) and protonymph, 3 in deutonymph (d1 added) and tritonymph, and 4 in adult (d2 added); palp tibia with 3 setae in larva and protonymph (1", 1', v'; tibial claw, d, excluded), 4 in deutonymph (d1 added) and later instars; palp tarsus similar to adult, except 1" becoming eupathidial in adult (Fig. 3 B)
Idiosoma. Nasal plate subtriangular in larva (Fig. 7 A) but anterior margin broader in succeeding instars. Prodorsal plate with 2 pairs of setae (ve and sce) in larva, seta ve short spiniform; 3 pairs in protonymph (a pair of clavate setae added near posterior margin of plate; Fig. 8 A, asterisked), ve becoming clavate. Opisthosoma with 3 dorsal plates (unpaired plate D and a pair of plate L) in larva; plate M form in deutonymph (Fig. 9 A), plate P form in tritonymph. Larva with 7 pairs of opisthosomal setae (c1, c2, d1, e1, f1, h1, h2; h2 on ventral side), pseudoanal seta ps or its vestige absent from pseudoanal valves; protonymph with 12 pairs and 1 unpaired median seta (d2, e2, unpaired median seta between setae h2, and ps1 – 3 added); adanal seta ad or its vestige absent from adanal plate; deutonymph with 14 pairs and 2 unpaired setae (f2, unpaired median seta between setae f1, and 1 pair of setae lateral to h1 added), a pair of vestige of ad present on adanal plate; tritonymph similar to deutonymph in numbers of dorsal opisthosomal setae, but ad becoming thickened spiniform or clavate; adult with 14 pairs and 3 unpaired setae (unpaired median seta between setae h1 added). Seta c2 relatively longer than other setae in larva but gradually shortened in succeeding instars until subequal to other setae in adult.
Coxal setation 2- 0-1 in larva (Fig. 7 B); Claparede’s organs typical; 3-1-2-2(4a included) in protonymph (Fig. 8 B; 1c, 3b, 4a, 4b added; 4a located on membranous integument); 5-1-2- 2 in later instars (Fig. 9 B – C; 1d, 1e added in deutonymph). Genital opening absent in larva, present since protonymph, with normal development of genital papillae: 1, 2, 3 pairs from protonymph to tritonymph, respectively; development of genital setae from protonymph to adult: 1-1-4-6; aggenital setae could not determined, obscured by neotrichous setae in para- and pro-genital region (Figs. 8 B, 9B – C), pool numbers of these setae, deutonymph to adult, 3-6-11.
Legs. Leg form generally similar to adult but femur I entire in larva (Fig. 7 C – E), proto- and deutonymph; faintly divided in tritonymph, and completely divided in adult. Solenidion present each on larval tibiae I–IV (φ) and tarsi I–II (ω) and constant throughout ontogeny; development of leg setae as follows.
—Trochanters: larva, 0-0-0; protonymph 3(l', v', l" added)-3(d, l', v' added)-1(d added)-0; deutonymph 4(v" added)-4 (v" added)-1-1(d added); tritonymph 6(l1', l1" added)-6(l", v1 ' added)-2(l" added)-3(l", l1" added); adult 6-8(d1, l1' added)-3(v' added)-4(v' added).
—Femora: larva 6(d, l', l", v', v", v1 ")-4(d, l', l", v')-4(d, l', l", v '); protonymph 7(d1 added)-5(d1 added)-4-1(d); deutonymph 10(d2, v1 ", v2 " added; l" becoming eupathidial)-6(v" added; l" becoming eupathidial)-4-4(l', l", v' added); tritonymph 12(l1', l1"; l' becoming eupathidial)-11(d2, d3, l1', v1 ', l1" added)-7(d2, l1", v")-6(d1, v" added); adult 15(d3, l2'ζ, l2"ζ added)-15(l2'ζ, l2"ζ, v1 ", v2 " added; l' becoming eupathidial)-10(l1', v1 ', v1 " added; l', l" becoming eupathidial)-10(l1', v1 ', l1", v1 " added; l' becoming eupathidial).
—Genua: larva 6(d, d1, l', l", v', v")-6(d, d1, l', l", v', v")-5(d, l', l", v', v"); protonymph 9(l1', l1", v1 ' added)- 8(l1', l1" added)-5-5(d, l', l", v', v"); deutonymph 13(d2, l2', v1 ", v2 " added; l" becoming eupathidial, v1 " unusually distal to v")-11(d2, l2', l2" added; l" becoming eupathidial)-5-5; tritonymph 17(d3, l3', l2", v2 ' added; l' becoming eupathidial)-14(d3, l3', v1 ' added; l1" becoming eupathidial)-7(l1', v1 ' added; l" becoming eupathidial)-5; adult 19(l4', l3" added; l2" becoming eupathidial)-17(l3", v1 ", v2 ' added; l2' becoming eupathidial)-10(l1", l2", v1 " added; l' becoming eupathidial)-9(l1', v1 ', l1", v1 " added; l', l" becoming eupathidial).
—Tibiae: larva 10(d, k, l', l", v', v", l1', l1", v1 ', v1 ")-8(d, l', l", v', v", l1', l1", v1 ')-6(d, l', l", v', v", v1 '); protonymph 11(v2 ' added)-8-6-6(d, l', l", v', v", v1 '); deutonymph 15(d1, l2', l2", v2 " added)-13(d1, l2', v2 ', l2", v1 " added; l" becoming eupathidial)-10(l1', l1", v2 ', v1 " added)-8(v1 ", v2 " added); tritonymph 20(d2, l3', v3 ', l3", v3 " added)-16(d2, l3', l3" added)-12(l2', v2 " added; l" becoming eupathidial)-13(l1', v2 ', v3 ', l1", l2" added); adult 22(l4', l4" added; l3" becoming eupathidial)-21(d3, l4', l4", v3 ', v2 " added; l2", l3" becoming eupathidial)-15(l3', v3 ', l2" added; l1"ζ becoming eupathidial or not)-16(l2', v4 ', v3 " added; l" becoming eupathidial).
—Tarsi (Figs. 7 C – E, 8C, 10–11): larva 15(l', l", p'ζ, p"ζ, v', v", l1', l1", v1 ', v1 ", l2', l2", v2 ', v2 ", ε)-13(l', l", p"ζ, v', v", l1', l1", v1 ', v1 ", l2', l2", v2 ', ε)-8(l', bt (= l"), v', v", l1', l1", v1 ', v1 "); protonymph 15-13-8-7 (bt (= l"), v', v", l1', l1", v1 ', v1 "); deutonymph 21(er', er", v3 ', v3 ", l3', l3" added; l" becoming eupathidial)-18(v2 ", l3', l3", v3 ', l4' added; l', l" becoming eupathidial)-12(er", l2', v2 ', v2 " added)-11(er', er", v2 ', v2 " added); tritonymph 24(l4', l4", v4 " added; l', l1" becoming eupathidial, v1 ', v1 " becoming so or not)-22(er', er", v3 ", l4" added; l1" becoming eupathidial)-15(er', l2", v3 " added)-14(l2', l2", v3 ' added); adult 28(l5', l5", v4 ', v5 ' added; l1' becoming eupathidial, l4" becoming so or not)-27(v4 ', v4 ", l5', l5", v5 ' added; l1', l4" becoming eupathidial, v1 ' becoming so or not)-17(v3 ', v4 ' added; l' becoming eupathidial)-17(v3 ", v4 ', v4 " added; er' becoming eupathidial).
Material examined. Holotype (female): THAILAND, Nan Prov., Wiang Sa Dist., Lai Nan Sub-dist (18°33'29.81"N, 100°47'48.67"E), 20 Mar 2012, col. M. Fuangarworn, ex moss on barks, 1 foot above ground. 20 paratypes (5 adults, 3 tritonymphs, 10 deutonymphs, 2 protonymphs) with same data as holotype. Other studied materials: One adult, Ayutthaya Prov., Tharua Dist., Salaloy Sub-dist. (14°31'75"N, 100°42'26"E), 23 Mar 2003, col. M. Fuangarworn, ex litter under Senna siamea (Lam.), field no. MF 2003-29. One adult, Samut Songkram Prov., Bang Khan Taek Sub-dist. (13°22'55"N, 99°59'40"E), 25 Mar 2003, col. M. Fuangarworn, ex tamarind litter, field no. MF 2003-41. One adult, 2 deutonymphs, Nakon Nayok Prov., Sarika Sub-dist. (14°18'05"N, 101°18'17"E), 7 Apr 2003, col. M. Fuangarworn, ex leaf litter in IPM pomelo orchard, field no. MF 2003-66. Thirty adults, 5 tritonymphs, Nan Prov., Sri Nan National Park, 4 May 2006, col. Naratip Chantarasawat, ex forest litter. One adult, 1 tritonymph, 1 deutonymph, Tak Prov., Sam Ngao Dist., Bhumipol Dam (17°14'46.35"N, 98°59'46.21"E), 2 Mar 2008, col. M. Fuangarworn, ex litter and soil, field no. MF2008-6. One adult, Chon Buri Prov., Sattaheep Dist., Kho Juang, 19 Mar 2011, col. M. Fuangarworn, ex forest litter, field no. MF 2011-44. Five adults, 1 tritonymph, 1 protonymph, Prachuap Khiri Khan Prov., Kho Thalu (11°4'14.40"N, 99°33'12.73"E), 14 Mar 2011, col. M. Fuangarworn, ex dry litter and topsoil under cliff, field no. MF 2011-28. Three adults, 3 tritonymphs, Saraburi Prov., Kaengkoi Dist., Chulalongkorn University Forest Reserve (14°31'33.78"N, 101°1'40.51"E), 3 Mar 2012, col. M. Fuangarworn, ex forest floor, hand collected. One adult, Krabi Prov., Mo Koh Lanta National Park, Koh Rok Nai (7°13'29.78"N, 99°4'13.48"E), 3 May 2013, col. M. Fuangarworn, ex root and rhizome of ferns on trunk, 1 foot above ground, field no. MF 2013-16. Three adults, Chaiyaphum Prov., Nong Bua Daeng Dist., Wat Pah Koeng (16°0'18.78"N, 101°53'33.49"E), 9 Jun 2013, col. M. Fuangarworn, ex bamboo litter, hand collected, field no. MF 2013-33. One protonymph, 1 larva, Mae Hong Son Prov., Mae Sariang Dist., ca. 30 km to Ban Sam Laeb (Rd. no. 1194), 14 Dec 2013, col. M. Fuangarworn, ex debris in fern basket at 1 m above ground, field no. MF 2013-57 - 58. Nine adults, Kanchanaburi Prov., Sai Yok Dist., Ban Wang Khamen, Plant Genetic Conservation Forest Reserve, near Manao Pee Cave, 22 Apr 2014, col. M. Fuangarworn, ex forest floor (hand collected), field no. MF 2014-22. Thirty adults, 5 tritonymphs, Kanchanaburi Prov., Sai Yok Dist., Ban Wang Khamen (14°12'3.28"N, 98°57'24.01"E), 22 Apr 2014, col. M. Fuangarworn, ex litter and soil, field no. MF 2014-23. Ten adults, 30 larvae, Ranong Prov., Ngaw Sub-dist., Ngaw Waterfall (9°51'17.27"N, 98°37'42.04"E), 24 Mar 2014, col. M. Fuangarworn, ex moss growing at base of a tree, field no. MF 2014-53. Holotype and most paratypes deposited in the Acarology Collection at the Chulalongkorn University Museum of Natural History, Bangkok, Thailand. One female paratype will be deposited in the Acarology Collection at the Ohio State University, Columbus, USA.
Etymology. The specific epithet of the new species ‘orientalis’ refers to its occurrence in the Oriental region. This species is widely distributed in Thailand and may be wider within the SE Asian mainland.
Distribution. Thailand (provincial records: Ayutthaya, Chaiyaphum, Chon Buri, Kanchanaburi, Krabi, Mae Hong Son, Nakon Nayok, Nan, Prachuap Khiri Khan, Ranong, Samut Songkram, Saraburi, and Tak).
Remarks. Neocaeculus orientalis sp. nov. is similar to N. nudonates Taylor, 2014 from Australia in having the trichobothrium sci clavate-capitate and the dorsal plate P divided. However, the new species may be distinguished from the latter by having the idiosoma rather broadly ovate (vs. narrower); the anterior margin of the prodorsal shield downturned and not projected (vs. not downturned but projected anteriorly); coxal setation of 5-1-2-1 (vs. 4- 1-1-1; 4a excluded); adanal setae present (vs. absent); and leg femur I divided (vs. entire). Comparisons of selected morphological characters of Neocaeculus species are presented in Table 1.
Ontogenetically, the idiosoma of the new species differs from that of N. luxtoni Coineau, 1967, the type species, in a) having reduced seta ve (as small spiniform setae) in larva (Fig. 7 A) but becoming clavate since protonymph; b) having relatively longer seta c2 but gradually shortened in succeeding instars; c) lacking of vestiges of pseudoanal setae on pseudoanal valves (segment PS) in larva; d) lacking of vestiges of adanal setae on paraproctal valves (segment AD) in protonymph but present in deutonymph and becoming clavate since tritonymph; e) seta e2 present since protonymph; and f) having setation of genital setae (protonymph to adult) of 1- 1-4-6 while N. luxtoni Coineau, 1967 has a) normal clavate seta ve since larva; b) seta c2 subequal to other dorsal setae throughout the developmental stages; c) vestiges of pseudoanal setae on pseudoanal valves (segment PS) in larva; d) vestiges of adanal setae on paraproctal valves (segment AD) in protonymph and becoming clavate since deutonymph; e) seta e2 present since deutonymph; and f) the setation of genital setae of 1-1-3-6.
Thailand is situated in the tropical monsoon climate zone, having alternating dry and wet periods, which seems to be unfavorable for caeculid mites—they are usually reported from dry and exposed habitats (Walter et al. 2009). Thus, it is not surprising that, despite a reasonably large number of collections from various localities, Thailand has only this new species of Caeculidae recorded so far. However, it is worth noting that this species seems well adapted to the environments in this biogeographic region. As shown above, this species has a nationwide (but disjunct) distribution, and can be found in litter and surface soils, moss on logs and tree bases, or basket ferns near ground level in forest habitats with a relatively closed canopy (evergreen and deciduous forests) as well as in scrub and plantations in rural areas. This species is abundant during the dry season, from about February to May (pers. obs.).
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description: Published as part of Fuangarworn, Marut & Butcher, Buntika Areekul, 2015, Neocaeculus orientalis sp. nov. (Acari, Trombidiformes, Caeculidae) from Thailand, pp. 251-268 in Zootaxa 4048 (2) on pages 252-266, DOI: 10.11646/zootaxa.4048.2.6, http://zenodo.org/record/244369