Ditha (Paraditha) shivanparaensis, Jeong & Harms & Johnson, 2024

Jeong, Kyung-Hoon, Harms, Danilo & Johnson, Jithin, 2024, A new species of Ditha (Pseudoscorpiones, Chthoniidae, Tridenchthoniinae) from the Western Ghats of India, with an identification key for the genus, Zoosystematics and Evolution 100 (1), pp. 1-8 : 1

Ditha (Paraditha) shivanparaensis sp. nov.

Figs 1 , 2 , 3 , 4

Type material.

Holotype (Fig. 2A, B ). Female (ADSH PST0001. INDIA: Kerala: Shivanpara, Mathikettan Shola National Park, Kerala, Idukki, 9°58'05.1"N, 77°13'43.5"E, altitude 1072 m, litter sample (sifting and Berlese trap), J. Johnson leg.

Paratypes (Fig. 2C, D ): 3 females (ADSH PST0003, ADSH PST0004, ZMH-A0013527) and one male (ADSH PST0002), same data as holotype.

Etymology.

This species is named after the hill ‘Shivanpara’ in the Mathiketan Shola National Park, where all specimens were collected.

Diagnosis.

Within the subgenus Ditha Paraditha , Ditha shivanparaensis sp. nov. closely resembles D. tonkinensis Beier, 1951 found in Vietnam in having an indistinct intercoxal tubercle between coxa III and IV, and presence of eight setae on the posterior margin of the carapace. However, the new species differs from D. tonkinensis and from all other species within the subgenus in having two accessory setae on the cheliceral palm. Ditha shivanparaensis sp. nov. also bears similarity to Ditha (Ditha) proxima (Beier, 1951) from Vietnam in terms of having two accessory setae on the cheliceral palm and 45-47 marginal teeth on the movable chelal finger. However, it differs from the latter in possessing 14 setae on the anterior margin of the carapace (as opposed to 10 setae in D. proxima ) and by the positioning of st, i.e., halfway between sb and t (whereas st is much closer to sb in D. proxima ).

Description.

Female, adult (holotype, Fig. 2A, B ).

Colour. Uniformly orange-brownish, the legs lighter than the body.

Chelicera (Figs 3F, H , 4D, E ). Cheliceral palm coarsely granulate and with seven setae (including two accessory setae), movable finger with one seta in medial position and seven marginal teeth, inner margin granulate; fixed finger with seven marginal teeth, the terminal one larger than the others (Fig. 3H ); with two dorsal lyrifissures; rallum with ten blades (Figs 3F , 4E ); serrula exterior with 16 blades of similar size.

Pedipalp (Figs 3G , 4B, C ). Trochanter 1.44 times, femur 3.54 times, patella 1.83 times, chela (with pedicel) 3.79 times, hand 1.51 times longer than broad, movable finger 1.54 times longer than hand. Femur, patella, chela smooth. Fixed chelal finger with six trichobothria, movable finger with four trichobothria, ib and isb situated basally on the dorsum of the chelal hand; sb, st, and t located separately from b; sb, st and t all spaced more than one areolar distance; st slightly closer to sb than t; eb, esb and ist forming a group at basal to subbasal position; esb slightly closer to ist than eb; est and it positioned at the median on the fixed finger; et closely located with xs, almost less than one areolar distance (Figs 3G , 4B ). Four lyrifissures on the dorsum of fixed chelal finger, one on the basal dorsum of chelal hand. Both fingers with small juxtadentate teeth; fixed finger with 55 triangular and retrorse teeth; movable finger with 47 rounded teeth.

Cephalothorax (Figs 3A, D, E , 4F, G ). Carapace 1.04 times longer than broad sub-rectangular; lateral margins almost parallel but slightly wide at the base; coarsely granulate, without furrows; four corneate eyes; anterior margin serrated; epistome small and serrated; with 94 setae; 14 setae on the anterior margin, eight setae on posterior margin; setae short and acuminate; with ten lyrifissures, three each on the sides near the anterior margin, one between each eye, and one on each side situated near the posterior margin (Fig. 3A ). Manducatory process with one long, acuminate setae, remainder of maxilla with ten setae; four lyrifissures on the maxilla. Coxal chaetotaxy: 10: 11: 11: 20 (Fig. 3D ). Coxa I with ca. 5-6 spines, each spine serrated terminally, and ca. 2-3 spines from one base; coxa II with ca. 5-6 spines (Figs 3E , 4E, F ); each spine serrated from the medial. Intercoxal tubercle indistinctly present between coxa III and IV, seta weakly present (Fig. 4F ).

Abdomen. Pleural membrane papillostriate, tergites undivided, but sternites III-IV partially divided; setae biseriate and acuminate. Tergal chaetotaxy, 14: 23: 23: 25: 26: 24: 24: 25: 21: 17: 13: 0. Sternal chaetotaxy, 15: 10: 8: 8: 8: 8: 8: 9: 12: 4: 2. Sternite I with 4 setae in the genital opening area.

Legs (Fig. 3B, C ). Leg I: trochanter 1.18 times, femur 3.87 times, patella 2.98 times, tibia 2.56 times, tarsus 5.93 times longer than broad, leg IV: trochanter 1.48 times, femur 2.75 times, tibia 3.44 times, metatarsus 2.57 times, tarsus 7.00 times longer than broad; leg IV: trochanter 1.67 times, femur 2.39 times, tibia 3.47 times, metatarsus 2.57 times, tarsus 5.49 times longer than broad. Tarsus of leg IV longer than the metatarsus; arolium undivided and shorter than the claws; pseudotactile seta located basally on leg I patella and medially on leg IV metatarsus.

Genitalia (Fig. 3J ). Typical shape of the genus Ditha . 15 setae in the genital opening area, including nine setae on the center of the opening and three setae each on either side of the opening; ten setae on the sternite III; six setae on the anterior part of sternite III; four setae on the posterior region, and two setae each on the part of sternite III.

Dimensions (in mm). Body length 1.47; Pedipalp: trochanter 0.22/0.15, femur 0.48/0.13, patella 0.27/0.15, chela (with pedicel) 0.72/0.19, movable finger 0.45, hand 0.29/0.19; Chelicera: total 0.32/0.18, movable finger 0.17; Cephalothorax: Carapace 0.47/0.45, anterior eye 0.005, posterior eye 0.004; Leg I: trochanter 0.13/0.11, femur 0.27/0.07, patella 0.19/0.06, tibia 0.15/0.06, tarsus 0.27/0.05; Leg IV: trochanter 0.16/0.11, femur + patella 0.47/0.17, tibia 0.33/0.10, metatarsus 0.15/0.06, tarsus 0.28/0.04.

Male, adult (paratype, Fig. 2 C, D ).

Same as the holotype, except slightly smaller (body length 1.291 mm).

Pedipalp. Trochanter 1.46 times, 3.54 times, patella 1.87 times, chela (with pedicel) 3.85 times, hand 1.47 times longer than broad, movable finger 1.56 times longer than hand; fixed finger with 50, movable finger with 48 teeth.

Cephalothorax. Carapace 1.06 times longer than broad; with 92 setae; 14 setae on the anterior margin, eight setae on the posterior margin; Coxal chaetotaxy: 10: 11: 11: 20. Coxa I with ca. 5-6 spines.

Abdomen. Tergal chaetotaxy, 10: 14: 15: 16: 19: 19: 19: 18: 16: 15: 13: 0. Sternal chaetotaxy, 10: 36: 6: 8: 10: 8: 13: 13: 11: 5: 2. Sternite II with nine total setae including six setae near the genital opening, sternite III with 38 total setae including 22 setae near the genital opening.

Legs. Leg I: trochanter 1.33 times, femur 3.65 times, patella 2.92 times, tibia 2.58 times, tarsus 5.80 times longer than broad; leg IV: trochanter 1.67 times, femur 2.39 times, tibia 3.47 times, metatarsus 2.57 times, tarsus 5.49 times longer than broad.

Genitalia (Fig. 3I ). Typical shape of the genus Ditha . 15 setae in the genital opening area, including nine on the center of the opening and three each on either side of the opening; ten setae on the sternite III; six setae on the anterior part of sternite III; four setae on the posterior region, and two setae each on the part of sternite III.

Dimensions (mm). Body length 1.29. Pedipalp: trochanter 0.19/0.13, femur 0.44/0.12, patella 0.24/0.13, chela (with pedicel) 0.64/0.17, movable finger 0.38, hand 0.24/0.17; Chelicera: total 0.30/0.16, movable finger 0.17; Cephalothorax: Carapace 0.42/0.39, anterior eye 0.005, posterior eye 0.004; Leg I: trochanter 0.12/0.09, femur 0.24/0.07, patella 0.16/0.06, tibia 0.39/0.09, tarsus 0.24/0.04; Leg IV: trochanter 0.18/0.11, femur + patella 0.40/0.17, tibia 0.31/0.09, metatarsus 0.14/0.05, tarsus 0.26/0.05.

Variation of female paratypes

(n=2). Pedipalp. Trochanter 1.44-1.46 times, femur 3.46-3.68 times, patella 1.85-1.98 times, chela (with pedicel) 3.65-3.74 times, hand 1.48-1.52 times longer than broad, movable finger 1.43-1.44 times longer than hand. Movable finger with 48, fixed finger with 53-54 marginal teeth.

Cephalothorax. Carapace 1.04 times longer than broad. 96-100 setae.

Abdomen. Tergal chaetotaxy, 13-14: 21-23: 22-24: 24-25: 24-25: 25: 25-26: 23-25: 18: 15-16: 14-15: 0. Sternal chaetotaxy, 10: 10: 8: 7-8: 9-11: 8-10: 8-9: 10: 11-13: 4: 2.

Legs. Leg I: trochanter 1.20-1.34 times, femur 3.60-3.93 times, patella 2.61-2.64 times, tibia 2.47-2.77 times, tarsus 5.88-6.08 times longer than broad, leg IV: trochanter 1.59-1.66 times, femur 2.38-2.53 times, tibia 3.40-3.55 times, metatarsus 2.17-2.29 times, tarsus 5.39-6.14 times longer than broad.

Dimensions (mm): Body length 1.33-1.41; Pedipalp: trochanter 0.21-0.22/0.15, femur 0.48-0.51/0.13-0.15, patella 0.28-0.30/0.15, chela 0.71-0.73/0.19-0.20, movable finger 0.41-0.43, hand 0.29-0.30/0.19-0.20; Chelicera: total 0.29-0.31/0.18-0.19, movable finger 0.18-0.19; Cephalothorax: carapace 0.46-0.47/0.45, anterior eye 0.005-0.006, posterior eye 0.004; Leg I: trochanter 0.12-0.13/0.10, femur 0.28/0.07-0.08, patella 0.17-0.19/0.07, tibia 0.14-0.16/0.06, tarsus 0.27/0.04-0.05; Leg IV: trochanter 0.21/0.13, femur + patella 0.43-0.44/0.17-0.18, tibia 0.35-0.37/0.10-0.11, metatarsus 0.14-0.15/0.06-0.07, tarsus 0.27-0.30/0.05.

Distribution.

Currently known only from the type locality.

Habitat.

The species was collected from moist leaf litter of montane ‘shola’ forests of the Mathiketan Shola National Park and is probably endemic to this mountain, although more field sampling is required to verify this.

Erratum.

The sequences with GenBank accession numbers OM792092.1, OM832661.1 and OM876917.1, previously attributed to the genus Compsaditha by Johnson et al. (2022), actually belong to the newly discovered species described herein as Ditha shivanparaensis sp. nov.

Key to the species of Ditha

1	Intercoxal tubercle distinct; 10-12 accessory seta positioned on the cheliceral palm	2, subgenus Ditha Ditha
-	Intercoxal tubercle indistinct or absent; 1-2 accessory seta positioned on the cheliceral palm	9, subgenus Ditha Paraditha
2	Cheliceral palm with less than six accessory setae	3
-	Cheliceral palm with more than six accessory setae	4
3	Carapace with less than 100 setae	D. proxima (Beier, 1951) (Vietnam)
-	Carapace with more than 100 setae	D. ogasawarensis Sato, 1981 (Japan)
4	Carapace with less than 150 setae	5
-	Carapace with more than 150 setae	6
5	12 setae on the anterior margin of the carapace	D. novaeguineae Beier, 1965 (Papua New Guinea)
-	14 setae on the anterior margin of the carapace	D. palauensis Beier, 1957 (Palau)
6	Tergite I with 12 setae in male	7
-	Tergite I with 21 setae in male	D. elegans Chamberlin, 1929 (Indonesia)
7	14 setae on the anterior margin of the carapace	D. philippinensis Chamberlin, 1929 (Philippines)
-	16 setae on the anterior margin of the carapace	D. loricata Beier, 1965 (Indonesia)
8	Intercoxal tubercle absent	10
-	Intercoxal tubercle indistinct	12
9	Intercoxal tubercle absent	10
-	Intercoxal tubercle indistinct	12
10	Posterior margin of carapace with 8 setae	11
-	Posterior margin of carapace with 14 setae	D. marcusensis (Morikawa, 1952) (Japan)
11	Carapace more than 70 setae	D. pahangica Beier, 1955 (Malaysia)
-	Carapace fewer than 70 setae	D. sumatraensis (Chamberlin, 1923) (Indonesia)
12	Carapace with more than 100 setae	D. laosana Beier, 1951 (Laos)
-	Carapace with fewer than 100 setae	13
13	Carapace with more than 70 setae	14
-	Carapace with fewer than 70 setae	D. sinuata (Tullgren, 1901) (Cameroon)
14	Pedipalpal femur at least 4 times longer than broad	D. latimana (Beier, 1931) (Tanzania)
-	Pedipalpal femur at least 4 times longer than broad	15
15	Chelicera with 1 accessory setae	D. tonkinensis Beier, 1951 (Vietnam)
-	Chelicera with 2 accessory setae	D. shivanparaensis sp. nov. (India)

Figures

Figure 1. Distribution of the Ditha (Ditha) and Ditha (Paraditha) species.

Figure 2. Habitus of Ditha shivanparaensis sp. nov. A. Female holotype, dorsal view; B. Female holotype, ventral view; C. Male paratype, dorsal view; D. Male paratype, ventral view. Scale bars: 1 mm.

Figure 3. Drawings of Ditha shivanparaensis sp. nov. (all paratypes unless mentioned otherwise) A. Carapace, dorsal view; B. Leg IV; C. leg I; D. Coxa; E. Coxal spines; F. Rallum; G. Left chela from the lateral; H. Cheliceral, dorsal view, two accessory setae in the box; I. Male genital area external view; J. Female genital area external view (holotype). Scale bars: 0.5 mm (A - D, G); 1 mm (E - F); 2 mm (H - J).

Figure 4. Ditha shivanparaensis sp. nov. A. Carapace, dorsal view; B. Left chela, lateral view; C. Left chela, dorsal view; D. Cheliceral, dorsal view; E. Rallum; F. Coxa (intercoxal tubercle in the circle); G Coxal spine. Scale bars: 200 µm (A-C); 100 µm (D, F); 30 µm (E); 50 µm (G).