Damarchus lanna Schwendinger & Hongpadharakiree 2023, sp. nov.
Creators: name: Schwendinger, Peter J.
name: Hongpadharakiree, Komsan
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Bemmeridae
Damarchus
Damarchus lanna

description: Damarchus lanna sp. nov.
Figures 5C, 7–10
Holotype. MHNG-ARTO-0034020; male (matured 11.X.1996); Lamphun Province, Mae Tha District, Doi Kunthan National Park, Doi Kunthan, below Camp Yutthasat 2, 18°29’56”N, 99°16’55”E, 950 m; 3.X.1995; leg. P.J. Schwendinger.
Paratypes. MHNG-ARTO-0034021; 1 male (matured mid-January 1993); from the type locality; 9.X.1992; leg. P.J. Schwendinger. MHNG-ARTO-0034022-0034023; 2 females (MHNG-ARTO-0034022 being the allotype); nearby locality, 18°29’54”N, 99°17’02”E, 980 m; 4.XI.1992; leg. P.J. Schwendinger. MHNG-ARTO-0034024; 1 female; nearby locality, near Camp Yutthasat 3, 18°29’44”N, 99°18’08”E, 1250 m; 17.II.1992; leg. P.J. Schwendinger. MHNG-ARTO-0034025-0034026; 1 male (matured 10.I.1989), 1 female; Thailand, Chiang Mai Province, Chomthong District, Doi Inthanon National Park, Doi Inthanon, near Huay Sai Lueang Waterfall, 18°31’08”N, 98°27’15”E, 1200 m; 26.XI.1987; leg. P.J. Schwendinger. MHNG-ARTO-0034027; 1 male (matured 17.II.1988); nearby locality, 18°30’54”N, 98°26’56”E, 1150 m; 15.VII.1987; leg. P.J. Schwendinger. MHNG-ARTO-0034028; 1 male (matured around 16.II.1988); Chiang Mai Province and District, Mae Hia Nai, 18°45’42”N, 98°55’13”E, 360 m; 12.XII.1987; leg. P.J. Schwendinger. MHNG-ARTO-0034029; 1 male (matured 21.II.1988); same locality; 7.I.1988; leg. P.J.Schwendinger. MHNG-ARTO-0034030; 1 female;same locality; 7.III.1986; leg. P.J. Schwendinger. MHNG-ARTO-0034031; 1 female; Chiang Mai Province and District, Doi Suthep-Pui National Park, Doi Suthep, 18°48’40”N, 98°54’42”E, 1200 m; 16.V.1987; leg. P.J. Schwendinger. MHNG-ARTO-0034032; 1 female; Chiang Mai Province, Mae On District, about 1 km S of Mueang On Cave, 18°46’09”N, 99°14’24”E, 410 m; 8.XII.1985; leg. P.J. Schwendinger. MHNG-ARTO-0034033-0034034; 1 male (matured around 15.II.1988), 1 female; Chiang Mai Province, Doi Saket District, near Ban Pong Kum, 18°55’12”N, 99°14’22”E, 450 m; 24.III.1987; leg. P.J. Schwendinger. MHNG-ARTO-0034035; 1 male (died during final moult on 24.II.1988); same locality; 5.XI.1986; leg. P.J. Schwendinger. THNHM; 1 female; same locality; 9.III.1987; leg. P.J. Schwendinger. THNHM; 1 male; Chiang Mai Province, Mae Rim District, Mae Rim, 18°53’40”N, 98°57’11”E, 360 m; 2014; leg. S. Sonthichai. MHNG-ARTO-0034038; 1 male (matured 18.III.1991); Chiang Mai Province, Chiang Dao District, Doi Chiang Dao, 19°24’47”N, 98°54’46”E, 560 m (= type locality of D. dao sp. nov.); 22.IX.1990; leg. P.J. Schwendinger. MHNGARTO-0034039; 1 male (matured 17.II.1988); nearby locality, 19°24’40”N, 98°52’46”E, 950 m; 25.VI.1986; leg. P.J. Schwendinger. MHNG-ARTO-0034040-0034041; 2 males (matured IX.2006 and 31.VII.2007); Nan Province, Tha Wang Pha District, Doi Wao, 19°06’42”N, 100°38’52”E, 1100 m (sample TH-05/16); 12.XII.2005; leg. P. Dankittipakul & S. Sonthichai. MHNG-ARTO-0034042; 1 female; Phayao Province and District, near Lake Phayao, 19°08’56”N, 99°53’20”E, 400 m; 12.I.1986; leg. P.J. Schwendinger. MHNG-ARTO-0034043; 1 male (matured 9.III.1992); Phrae Province and District, near Ban Nam Klai, 18°01’38”N, 100°17’30”E, 600 m; 20.IX.1991; leg. P.J. Schwendinger. MHNG-ARTO-0034044; 1 female; Tak Province, Mae Sod District, Doi Musoe (= Doi Muser), 16°45’14”N, 98°54’10”E, 950 m; 18.IX.1990; leg. P.J. Schwendinger.
Other material. MHNG; 2 juveniles; Chiang Mai Province, Mae On District, about 1 km S of Mueang On Cave, 18°46’09”N, 99°14’24”E, 410 m; 9.I.1986; leg. P.J. Schwendinger. MHNG; 6 juveniles; Chiang Mai Province, Doi Saket District, near Ban Pong Kum, 18°55’12”N, 99°14’22”E, 450 m; leg. P.J. Schwendinger.
Etymology. The species epithet, a name in apposition, refers to “Lan Na Thai”, a former kingdom (founded in the 13 th century) in northern Thailand.
Diagnosis. Most similar to D. pylorus sp. nov., males distinguished by possessing only a small, laminar, prolaterad-directed para-embolic apophysis (long, claw-like and distad-directed in D. pylorus sp. nov.; Fig. 7M–R cf. Figs 1G–I, 2C–F); females distinguished by leg I not distinctly darker than leg II, by patellae I–II mostly longer than metatarsi I–II (patellae I–III mostly longer than corresponding metatarsi in D. pylorus sp. nov.), by having much longer sperm receptacles and by lacking small sclerotized lateral spots in the genital atrium (Fig. 10 cf. Fig. 4). Distinguished from all other known congeners but D. pylorus sp. nov. by males possessing a palpal organ with a para-embolic apophysis and a keel composed of a series of laminae on its lower (proximal) surface (Fig. 7M–R; absent in most other described congeners, e.g., Fig. 11K–M); females distinguished from those of other congeners but D. pylorus sp. nov. by possessing sperm receptacles with a large, strongly sclerotized base and a narrower, unsclerotized head (Fig. 10; no such division in most other described congeners, e.g., Fig. 13).
Description of male holotype. Colour in alcohol: Pars cephalica of carapace and distal part of chelicerae mostly dark brown, pars thoracica brown, with dark radial bands on coxal elevations (Fig. 7A). Proximal part of chelicerae brown; fangs black-brown. Labium, sternum, palpal coxae and ventral side of palpal femora darker than leg coxae (Fig. 7C). Legs and palps mostly brown; distal articles generally slightly lighter than proximal articles except for dark distal portion of tibia I and dark proximal portion of metatarsus I (Fig. 7H–I); metatarsus I and tarsus I darker than metatarsi and tarsi II–V. Opisthosoma dorsally light greyish brown (Fig. 7E); ventral side mostly cream-coloured, except for light brown booklung covers and genital region; spinnerets cream-coloured.
Morphology and measurements: Body 18.02 long. Carapace 6.28 long, 4.96 wide, its anterior margin recurved, its posterior margin slightly and widely invaginated (Fig. 7A); pars cephalica indistinctly arched, its slope continuous with that of pars thoracica, with a crescent-shaped shallow depression on each side at border between pars cephalica and pars thoracica (Fig. 7B); few thin hairs scattered over pars cephalica, longer and stronger ones on, in front of and behind eye mound; pars thoracica without hairs in anterior portion and with long strong bristles, some of them wavy, in posterior part; several even stronger bristles along lateral carapace margin (Fig. 7A). Eight eyes on low but distinct mound (Fig. 7B); eye group 0.61 long, anterior eye row straight, 1.14 wide, posterior eye row slightly recurved, 1.16 wide. MOQ 0.49 long, 0.61 wide anteriorly, 0.83 posteriorly. Eye diameters: AME 0.27, ALE 0.33, PME 0.22, PLE 0.26. Fovea widely U-shaped, without prefoveal setae, 0.66 wide, occupying 14% of carapace width at that point. Proximal article of chelicera 2.40 long, fairly strong, without intercheliceral tumescence; ventral groove with 7/8 teeth arranged in a medially transposed row (as in Fig. 3I showing D. pylorus sp. nov. female) on promargin and a short row of 10/12 tiny light-coloured medioproximal denticles; rastellum sessile, composed of five strong short spines in a transverse row and several weaker and more pointed spines above fang articulation. Palpal coxa 2.27 long, 1.12 wide; anterior lobe short, without serrula; with about 50 pointed cuspules in prolateral-proximal corner. Labium 0.58 long, 0.95 wide, with three short to medium-long, pointed cuspules (Fig. 7D). Sternum 3.47 long, 2.69 wide; labiosternal suture quite long and deep at posterior margin, fused with anterior pair of sigilla; three pairs of free sigilla, anterior pair smallest and closest to sternal margin, median pair slightly larger and further away from margin than anterior pair, posterior sigilla ellipsoid, about two times longer than wide, even more remote from margin, medially separated from each other by about their length (Fig. 7C).
Palp (Fig. 7M–R) 6.20 long (2.48 + 0.99 + 1.82 + 0.91), without spines. Tibia ventrally with several long strong bristles; retrolaterally with a field of stiff bristles in distal half (Fig. 7N–O). Tarsus short, without spines, strong bristles or scopula, distally with three short lobes. Trichobothria: 7+7/ 8 in two rows on tibia, nine in an irregular row on tarsus. Palpal organ (Fig. 7P–R) quite short and robust, with wide transition between bulbous part and embolus; para-embolic apophysis in the form of a widely triangular lamina with an finely dentate distal margin, situated in that transition zone and directed prolaterad (best seen in frontal view, Fig. 7Q); embolus flagelliform, slightly curved and indistinctly dentate along its inner (prolateral) side; lower (proximal) surface of palpal organ with a distinct keel formed by a series of small fish-scale-like or shark-tooth-like laminae decreasing in length towards embolus (Fig. 7P, R).
Legs 3214. Leg I 18.52 long (5.12 + 2.98 + 4.30 + 3.72 + 2.40); leg II 16.06 long (4.46 + 2.56 + 3.51 + 3.22 + 2.31); leg III 13.40 long (3.60 + 2.11 + 2.15 + 3.43 + 2.11); leg IV 19.50 long (5.21 + 2.60 + 4.63 + 4.83 + 2.23). All patellae shorter than corresponding metatarsi. Leg tarsi not pseudosegmented and without spines, with a light ventral scopula being thinner on legs III–IV than on legs I–II; tarsi I–II slightly spindle-shaped, tarsi III–IV cylindrical, all more or less distinctly curved upward. Scopulae covering entire ventral side of all tarsi, plus distal half of metatarsi I–II, distal fourth of metatarsus III and distal sixth of metatarsus IV (indistinct). Metatarsal preening combs absent on leg I; indistinctly developed proventrally, absent retroventrally on leg II; indistinctly developed proventrally, distinctly developed retroventrally on leg III; absent proventrally, distinctly developed retrolaterally on leg IV. Leg I: Metatarsus slightly bent downward in proximal half, below (posterior to) midpoint with a knob-shaped proventral process densely covered with numerous cuspules (Fig. 7H–I, K–L); tibia cylindrical, not incrassate but distinctly thicker than metatarsus I, with a fairly long, digitiform proventral coupling spur tipped by a shorter arrowhead-shaped megaspine (Figs 7H–I, 8C).
Spines: Leg I: femur p1; tibia v3 (two thin spines plus a megaspine on coupling spur); metatarsus p0/1, r1, v5. Leg II: femur p1; tibia v4 (proventral-distal one weakest); metatarsus p0/1, v3/5 (proximal two weakest). Leg III: patella p3; tibia p2, r2, v5/6 (2 posteriors weakest); metatarsus d6/7, p2/3, v3. Leg IV: tibia v4/5; metatarsus d3, v5. Trichobothria: 7–10+ 9–12 in two rows on tibiae, 10–18 in a single irregular row on metatarsi, 9–12 in a single zig-zag row on tarsi. Paired tarsal claws with 7–9 teeth in a S-shaped row on legs I–II, 6–7 on legs III–IV; unpaired claw tiny on legs I–III (Fig. 7G), small and bare on leg IV.
Opisthosoma oval (Fig. 7E), 8.51 long, 5.29 wide; dorsal side densely covered with short and long dark bristles, ventral side less densely covered with only short bristles. PMS 0.70 long, separated from each other by 0.45 (about 1.5 times their width); PLS 3.55 long (proximal article 1.49, median article 0.99, distal article 1.07), separated from each other by 1.16 (almost twice diameter of proximal article).
Description of female allotype. Colour in alcohol: As in male, except for the following. Carapace with brown pars cephalica; anterior part of eye mound black, posterior part dark brown; pars thoracica lighter, with indistinct dark radiating bands on coxal elevations (Fig. 9A). Cheliceral claw black. Palpal coxae, labium and sternum orange-brown, slightly darker than leg coxae (Fig. 9C). Legs mostly brown, except for light yellow-brown patellae, tibiae and proximal part of metatarsi of legs I–II. Opisthosoma dorsally grey-brown (Fig. 9H, showing different female), ventrally mostly cream-coloured, with light brown book-lung covers, genital area(Fig. 9F) and spinnerets (Fig.9 G-H).
Morphology and measurements: Body 17.77 long. Carapace 7.15 long, 4.96 wide, its anterior margin very slightly recurved, its posterior margin widely invaginated (Fig. 9A); pars cephalica in profile more strongly arched than in male (Fig. 9B cf. 7B); with a slightly curved lateral depression on each side at transition between pars cephalica and pars thoracica; hairs in median row behind eye mound longer and stronger than in male, hairs on pars thoracica much weaker (Fig. 9A cf. 7A). Fovea widely U-shaped, 0.91 wide, occupying 20% of carapace width at that point. Eye mound low but distinct; eye group 0.69 long, anterior eye row straight, 1.26 wide, posterior eye row slightly recurved, 1.23 wide. MOQ 0.60 long, 0.65 wide anteriorly, 0.89 posteriorly. Eye diameters: AME 0.35, ALE 0.41, PME 0.28, PLE 0.27. Proximal article of chelicera 2.64 long, stronger than in male, without intercheliceral tumescence; ventral groove with eight teeth arranged in a medially transposed row on promargin and a short band of 14 tiny black medioproximal denticles; rastellum sessile, composed of about 20 strong short spines in several rows and several similarly thick but more pointed spines above fang articulation. Palpal coxa 2.98 long, 1.53 wide; no serrula; with over 80 domed cuspules in prolateral-proximal corner. Labium 0.70 long, 1.36 wide, with two domed cuspules (Fig. 9D). Sternum 4.05 long 2.85 wide; posterior pair of sigilla more than two times longer than wide, medially separated from each other by about 80% of their length (Fig. 9C).
Palp 8.89 long (2.98 + 1.82 + 2.07 + 2.02). Spines: patella p1, tibia p3/4, v6 (3 posteriors long and weak), tarsus v1/2. Tibia dorsally with indistinct pallid subdistal pseudosegmentation (Fig. 9E). Tarsus with scopula covering entire length of article proventrally but only its distal half retroventrally; palpal claw with seven teeth in proventral row. Trichobothria: 8+ 9 in two rows on tibia, 11/ 17 in an irregular row on tarsus.
Legs 3214; leg I without modifications. Leg I 16.28 long (4.63 + 3.14 + 3.47 + 3.06 + 1.98); leg II 13.60 long (3.80 + 2.73 + 2.69 + 2.64 + 1.74); leg III 11.15 long (3.14 + 2.27 + 1.61 + 2.56 + 1.57); leg IV 16.65 long (4.55 + 2.81 + 3.88 + 3.80 + 1.61). Patellae I–II longer than metatarsi I–II; patellae III–IV shorter than corresponding metatarsi. Scopulae covering entire ventral side of leg tarsi I–II, plus distal three-fourths of proventral side and two-thirds of retroventral side of metatarsus I, plus distal two-thirds of proventral side and distal half of retroventral side of metatarsus II; no scopulae on legs III–IV. Metatarsal preening combs absent on leg I, on metatarsus II present only proventrally, on metatarsi III–IV present proventrally and retroventrally.
Spines: Leg I: femur p1; patella p1; tibia p3, v3; metatarsus p1, v5/6. Leg II: femur p1, patella p1; tibia p2, v3; metatarsus p1, v6/7. Leg III: patella p3; tibia p2, r2, v6 (all long and weak); metatarsus d12, v4/5. Leg IV: tibia v7 (all long and weak); metatarsus d3, v6. Trichobothria: 8–9+ 11 in two rows on tibiae I–II, 8–12+9–13 on tibiae III–IV; 18 in a single irregular row on metatarsi I and IV, 15 on metatarsus II, 10/14 on metatarsus III; 16 in a single zig-zag row on tarsus I, 12–14 on tarsi II–IV. Dense patches of rather strong (more so than in females of D. pylorus sp. nov. and D. dao sp. nov.) spinules dorsally on patella III and patella IV (on the latter spinules becoming thinner in distal half), divided by an oblique glabrous band, plus a dorsodistal group of strong spinules on femur IV. Paired tarsal claws with 5–6+6–7 teeth in two rows on legs I–II, 4+5–6 on legs III–IV; unpaired claw tiny on legs I–III, small on leg IV, all without denticles.
Opisthosoma oval (Fig. 9H, showing different female), 8.02 long, 6.28 wide, with hair cover as in male. PMS 0.74 long, separated by 0.37 (slightly less than their diameter); PLS 3.63 long (proximal article 1.40, median article 1.07, distal article 1.16), separated by 0.87 (slightly more than diameter of proximal article) (Fig. 9G–H).
Vulva (Fig. 10A): Genital atrium relatively wide and long; no sclerotized lateral spots (as present in vulvae of D. pylorus sp. nov., Fig. 4A–D) discernible. A single pair of widely separated receptacles situated on ventral side of atrium, away from its anterior margin. Each receptacle composed of a nearly conical, strongly sclerotized base and a digitiform, unsclerotized head; the latter penetrated by gland pores only at its apex.
Variation. Carapace lengths in males (n = 13) range 5.15–8.45, in the largest (from Doi Inthanon, 1200 m) of 10 females measured it is 8.87; carapace widths in males range 3.92–6.91, in the largest female it is 6.49. All but two males (from Doi Inthanon, 1200 m and from Mae Hia Nai, 360 m) and one female (from Doi Suthep, 1200 m) have a more or less distinct light median dorsal spot in the anterior third of the opisthosoma (Figs 7E, 9H). Most specimens have three short prolateral spines on patella III; one male has 2/3 spines, another male 4/4 spines there; one female has 1/3. Females have patella I slightly longer than or as long as metatarsus I, patella II always slightly or distinctly longer than metatarsus II, and patellae III–IV always shorter than metatarsi III–IV (see also Discussion). Most females have an indistinct dorsal pseudosegmentation subdistally on the palpal tibia (Fig. 9E); only in one female, this is rather distinct. In all males, the unpaired tarsal claw is absent or tiny on legs I–III and small on leg IV. In all females, it is tiny on tarsi I–III and well-developed on leg IV. The number of labial cuspules in males ranges from zero (one specimen) to four (one specimen); they are either short and domed (as in conspecific females) or distinctly longer and pointed (Fig. 7D). Females have 1–4 short and domed labial cuspules (Fig. 9D). The shape of the apical megaspine on the proventral tibia I coupling spur ranges from short with a widely arched apex (Fig. 8A–B) to medium-long with a narrowly arched apex (shark-tooth-shaped, the most common form observed; Fig. 8C) and to long with a pointed apex (Fig. 8D). Variation in vulva morphology is shown in Fig. 10. The unsclerotized receptacular heads are either rather short and club-shaped (e.g., Fig. 10C) or longer and digitiform (e.g., Fig. 10B); they are always longer than the sclerotized receptacular base, often distinctly so.
Relationships. This new species is most similar and probably closely related to D. pylorus sp. nov. Both possess a reduced unpaired tarsal claw on legs I–III, a proventral process bearing a cluster of cuspules on metatarsus I of males, and unusual modifications of the palpal organ [i.e., a coarsely dentate keel on the lower (posterior) side and a para-embolic apophysis] and of the vulva (i.e., a relatively long genital atrium having on its ventral side receptacles composed of a strongly sclerotized base and an unsclerotized head). See also Discussion.
Distribution. The new species is quite widely distributed throughout at least six provinces of northern Thailand. It also has a wide altitudinal range, having been collected between 360 m and 1250 m.
Biology. Habitat and distribution: The spiders examined were collected from moderately sloping to vertical earth banks and road sides, mostly in dry secondary forests, also in wasteland and in a dry evergreen forest (at the foot of Doi Chiang Dao; at the type locality of D. dao sp. nov.). At higher altitudes, these spiders were only found at road sides, not inside nearby evergreen hill forests.
Burrow: The burrow of D. lanna sp. nov. (Fig. 5C) is quite typical for the genus Damarchus. It is composed of a main shaft, up to 24 cm long and with an open entrance that is usually level with the ground or slightly elevated; a few burrows had the burrow entrance raised on a 1–2 cm high, rigid and not foldable soil turret. From the upper part of the main shaft a side shaft (up to 9 cm long) branches upward to just below the soil surface. In the latter it closely resembles burrows of Australian wishbone spiders (Anamidae; see Main 1982: 25, fig. 1; Main 1984: 70, plate 10). Only a single burrow was found in which the side shaft opened to the surface, thus creating two open entrances. This is atypical for the species, if not an artefact of accidentally opening the blind end of the side shaft during inspection. At the mouth of the side shaft there is a silken collar with prey remnants glued to its outside, which can be pulled shut by the spider. Typical for this species is another prey remnant deposit in the main shaft, just opposite the mouth of the side shaft. In many burrows, further prey remnants were found at the bottom of the main shaft. Although the side shaft probably serves as a refuge for the spider, it was in most cases found sitting at the bottom of the main shaft.
Phenology: Males were collected mature in the field or became mature in captivity in Chiang Mai between the end of July and late March. Males from relatively high-altitude localities (950–1200 m) were generally later (maturing between the end of July to mid-February) than males from lower altitudes (360–600 m), which matured between mid-February to late March. A pregnant female collected at 450 m at the beginning of June laid eggs in captivity (in Chiang Mai) in early July. A month later, in early August, 47 second instar spiderlings emerged. Another female with an egg sac containing 27 eggs was found at the beginning of August, at 450 m altitude.
Parasites: Two cases of parasitism were observed: 1) in early March at Mae Hia Nai (360 m) a female was collected with a parasitoid hymenopteran larva attached to its opisthosoma; 2) at about the same time on Doi Inthanon (1250 m) a burrow was excavated which contained 11 fly pupae among the fresh remains of a spider.
description: Published as part of Schwendinger, Peter J. & Hongpadharakiree, Komsan, 2023, Three new and exceptional Damarchus species from Thailand (Araneae: Bemmeridae), pp. 481-508 in Zootaxa 5336 (4) on pages 489-496, DOI: 10.11646/zootaxa.5336.4.2, http://zenodo.org/record/8282032