Lathys humilis (Blackwall, 1855)

Marusik, Yuri, Koponen, Seppo & Fritzén, Niclas, 2009, On two sibling Lathys species (Araneae, Dictynidae) from northern Europe, ZooKeys 16 (16), pp. 181-195 : 184-189

Lathys humilis (Blackwall, 1855)

Figs 1-3 , 7-9 , 13-16 , 20-22 , 26-27

L. h.: Wiehle 1953: 102, f. 222-227 (♁ ♀).

L. h.: Thaler 1981: 127, f. 77-79, 85-86 (♁ ♀).

L. h.: Almquist 2006: 319, f. 280a-h (♁ ♀).

For other references, see Platnick (2009). Some of them may refer to L. nielseni or other species.

Misidentifications:

L. h.: Schenkel 1936: 14, f. 1a-b (♀). May refer to undescribed species.

L. h.: Lehtinen 1967: 242, f. 264 (♁). Refers to L. nielseni .

L. h.: Palmgren 1977: 22, f. 4.20-24 (♁ ♀). Refers to L. nielseni .

L. h.: Paik 1978: 185, f. 75.1-5 (♀). Seems to refer to L. maculosa (Karsch, 1879) . L. h.: Hu 1984: 60, f. 55. 1-2 (♀). Refers to L. nielseni .

L. h.: Zhu 1985: 58, f. 48a-c (♁). May refer to L. nielseni or to L. annulata .

L. h.: Song et al. 1999: 364, f. 215N (♁). May refer to L. nielseni or to L. annulata . L. h.: Song et al. 2001: 287, f. 181A-B (♁). May refer to L. nielseni or to L. annulata .

Material examined. DENMARK: 1♀ ( ZMT: AA 11.130 ), Bornholm Isl., Ibsker, Paradisbakkerne Grydedal , in small sphagnum beds around a small pond, 30.06.1967 (P.T. Lehtinen) . BULGARIA: 1♀ ( ZMMU), Blagoevgrad Distr., Rila Mt. range, ESE slope of Karpatnik Mt., Bodovitsa River Valley , right riverside, ca 3.8 km WNW of Bachevo, Pinus – Fagus forest, 41°56’12”N, 23°24’09”E, 1230 m, 10.08.2005 ( A. Gromov) . UKRAINE: 35♁ ♀ ( ZMUT, ZMMU) Crimea, Simferopol Distr., Chatyr-Dagh Mt. , 23.04.2000 (D.S. Letova) ; Feodosya Distr., Karadag Nature Reserve, Kara-Agach Mt. , Juniperus excelsa , sweeping, 14- 16.05.2008 ( A. A. Nadolny ) ; Yalta Distr., Martyan Cape Reserve , 30.04.- 13.05.2007 (M.M. Kovblyuk) ; 1♁ ( ZMMU), Ternopil’ Area, environs of Dzvynyach Village , old nest of Sylvia atricapilla , on bush 0.9 m above the ground, 5.05.2006 (M. Fedo- ryak) . AZERBAIJAN: 2♁ 31♀ ( ZMMU), SE Azerbaijan, Lenkoran Dist., environs of Aurora Village , 38°40’N 48°52’E, 23- 28.04.2001 (Yu.M. Marusik) ; 1♁ ( ZMMU) same locality and collector, 21- 29.05.2003 ; 2♀ ( ZMMU), SE Azerbaijan, Lenkoran Distr., Hyrcan Reserve, environs of Apo Village , 38°38’N 48°47’E, 28.05.2003 (Yu.M. Marusik) ; 1♁ ( ZMMU), SE Azerbaijan, ca 10 km W of Astara Village , Isti-Su, 38°27’N 48°47’E, 25.04.2001 (Yu.M. Marusik) . IRAN: 2♀ ( ZMMU), Mazandaran Prov., Nashtarood-Khoshkadaran , 51.033°E 36.750°N, 9- 10.06.2000 (Yu.M. Marusik) .

Description. Measurements (Crimean specimens). Male. Total length 1.7; carapace 0.9 long, 0.7 wide, 0.4 high; chelicerae 0.5 long. Variation (n=2): total length 1.6-1.7; carapace 0.8-0.9 long, 0.6-0.7 wide; 0.4 high.

Length of leg segments:
	femur	patella	tibia	metatarsus	tarsus	total
I	0.8	0.3	0.7	0.6	0.4	2.8
II	0.6	0.3	0.5	0.5	0.3	2.2
III	0.5	0.2	0.4	0.4	0.2	1.7
IV	0.6	0.2	0.5	0.5	0.2	2.0
Female. Total length 1.9; carapace 0.8 long, 0.6 wide, 0.4 high; chelicerae 0.4 long. Variation (n=3): total length 1.9; carapace 0.8-0.9 long; 0.6 wide, 0.4 high. Length of leg segments:
	femur	patella	tibia	metatarsus	tarsus	total
I	0.7	0.2	0.6	0.5	0.3	2.3
II	0.6	0.2	0.4	0.4	0.2	1.8
III	0.5	0.2	0.3	0.4	0.2	1.6
IV	0.6	0.2	0.4	0.5	0.2	1.9

Colouration. Carapace in both sexes without distinct pattern. Males slightly dark- er than females. Abdomen with distinct pattern consisting of white guanine dots, black pigment (cardiac mark, sides, and wide posterior band). Legs with distinct annulations.

Copulatory organs. Male palp ( Figs 7-9 , 13-16 ) with patellar apophysis, tibia with three apophyses (retrolateral dorsal, retroventral and retrolateral (or intermediate) that fix (lock) terminal part of conductor. Conductor very long with two arms. Upper arm coiled, and terminal part spine-like and slightly twisted. Epigyne as in Figs 20 , 26-27 with one shallow fovea, and copulatory openings placed in apical-lateral part of fovea. Receptacula droplet-shaped. Insemination ducts short and forming one turn.

Diagnosis. Lathys humilis can be easily distinguished from the closely related L. nielseni by the abdominal pattern consisting of dark stripes and white spots formed from guanine deposits ( Figs 1-3 ). White guanine deposits are totally absent in L. nielseni ( Figs 4-6 ). The two species can also be separated on the basis of the copulatory organs. The epigyne of L. humilis has shorter insemination ducts turned upwards in

the place where they are attached to the spermathecae. The females also differ in the shape of the fovea (cf. Figs 20 , 30 ). In L. humilis the epigynal fovea is subdivided by the septum, fovea deep with distinct margins (there is no septum and there are no distinct margins of the fovea in L. nielseni ). The male palps of the two species are more similar than the epigynes. The two species can be separated by the thicker and broader patellar apophysis in L. humilis , the shape of the dorsal tibial apophysis, and the thicker and longer tip of the conductor in L. humilis .

L. humilis can be distinguished from the Japanese L. annulata , treated for a long time as a junior synonym, by its droplet-shaped spermathecae and its shorter insemination duct forming one loop only (vs. round spermathecae and insemination ducts forming several coils, cf. figs 10-12 in Ono 2003).

Distribution. According to the Platnick’s (2009) catalogue, this species has a Palaearctic (=trans-Palaearctic) distribution with several records from China (Shandong, Anhui, Shanxi and Gansu), Taiwan and Korea. Judging from the figures of the Chinese specimens, all records of L. humilis refer to L. nielseni or another species (males of L. annulata are unknown). Judging from the figures (cf. Fig. 32 ) the record of this species from Shandong ( Hu 1984) refers to L. nielseni . Other records of L. humilis from eastern China based on males may also refer to L. nielseni or L. annulata . The actual species belonging of “ L. humilis ” from Gansu ( Schenkel 1936) remains unclear. Figures of the epigyne made by Schenkel are dissimilar to those of L. humilis or L. nielseni . The specimen stored in the Swedish Museum of Natural History, Stockholm lacks an epigyne and the abdominal pattern is indistinct. The record of this species from Korea ( Paik 1978) refers to L. maculosa (Karsch, 1879) , which belongs to the Lathys stigmatisata -group. According to our studies of the Palaearctic Lathys , L. humilis seems to be distributed from western Europe to Caucasus and Mazandaran, northern Iran (see “material examined”). The overlapping ranges of L. humilis and L. nielseni in SW Sweden may be caused partly by misidentifications. Both species were found, however, in samples from Öland in the Swedish Museum of Natural History.

Habitats. According to Hänggi et al. (1995), L. humilis is found in Europe especially in coniferous forests (both spruce and pine), on the forests’ edges, in field shrubs and hedges, and less frequently in deciduous forests. It has been collected mostly on trees, both in canopies and on stems ( Hänggi et al. 1995). According to Roberts (1995), in Great Britain it occurs on bushes and trees with small, hard leaves (heather, gorse, box, yew). Harvey et al. (2002) reported this species from bushes and trees in woodland and scrub, on oak, yew, pines, gorse, etc. It may also be fairly common on ornamental evergreen and privet hedges in parks and gardens; juveniles overwinter in leaf litter, brushwood, under bark and in other similar places ( Harvey et al. 2002). In Sweden the species was reported from litter in dry pine forests, from Calluna -stands and from litter in woods with oaks and on limestone ( Almquist 2006).

Note. Lehtinen (1967) synonymised three species with L. humilis : L. annulata ( Japan) , Altella nielseni Schenkel, 1932 ( Sweden) and Altella lathysoides Denis, 1937 ( Algeria) . The first two names were removed from synonymy by Ono (2003) and Thaler (1981) respectively.

Figures

Figures 1-6. Habitus and pattern of Lathys humilis (1-3) and L. nielseni (4-6) 1, 4 male, dorsal 2-3, 5-6 female, dorsal 1-2 from Crimea 3 from Azerbaijan 4-5 from Finland 6 from Ural.

Figures 7-12. Male palp of Lathys humilis (7-9, from Crimea) and L. nielseni (10-12, from Finland) 7, 10 ventral 8, 11 retrolateral 9 bulbus, retrolateral 12 bulbus, dorsal 12 after Marusik et al. (2009).

Figures 13-19. Male palp of Lathys humilis (13-16 from Crimea) and L. nielseni (17-19 from Finland) 13, 17 retrolateral 14, 18 ventral 15-16, 19 patella, tibia and base of cymbium, retrolateral-dorsal, different turns 13, 15 after Marusik et al. (2009). Scale = 0.1 mm if not otherwise indicated.

Figures 20-25. Epigyne and male chelicera of Lathys humilis (20-22 from Crimea) and L. nielseni (23- 25 from Finland) 20, 23 epigyne, ventral 21, 24 frontal 22, 25 inner 20 from Azerbaijan 21-22 – from Crimea. Scale = 0.1 mm.

Figures 26-32. Epigyne of Lathys humilis (26-27) and L. nielseni (28-32) 26, 28-29 digital photograph of epigyne, ventral 27, 30 epigyne after maceration, ventral 31-32 epigyne, dorsal 26-27 from Crimea 28, 30-31 from Finland 29 from Ural 26 after Marusik et al. (2009) 32 after Hu (1984). Scale = 0.1 mm.