Neodietrichia depressum ( Emerton, 1882 ) Milne & O’Neil & Bertaux, 2023

Milne, Marc A., O’Neil, Caylie & Bertaux, James, 2023, A taxonomic revision of Neodietrichia (Araneae: Linyphiidae), a rarely encountered but widespread spider taxon, Zootaxa 5296 (1), pp. 31-44 : 37-41

Neodietrichia depressum ( Emerton, 1882) new combination

( Figs. 1 , 4 , 5 , 8 , 9 )

Lophocarenum depressum Emerton 1882: 50 , fig. 6 (Description of male).

Erigone depressa Marx 1890: 533 .

Diplocephalus depressus Simon 1894: 615 .

Lophomma depressum Crosby & Bishop 1933: 125 , figs. 64–68.

“ Lophomma ” depressum Marusik, Gnelitsa & Koponen, 2006: 166 , figs. 43–48, 78–83 (misplaced in this genus).

Type. Holotype male. U.S.A.: New Hampshire: 1 male, Coös County, Mount Washington , June 1874, J. H. Emerton ( MCZ 21047 ).

Diagnosis. Males of N. depressum n. comb. possess a palp with a ventrally-projecting distal portion of the embolus with most of the embolus hidden while the embolus in N. hesperia visibly projects anteriorly towards the radical apophysis ( Figs. 2B, E , 3A , 4B, E , 5A ). Moreover, the palpal tibial apophysis in N. depressum n. comb. is wider than that of N. hesperia and possesses a median keel in addition to smaller distal spines, which differs from the straight and flat palpal tibial apophysis in N. hesperia that possesses 1–2 large spines ( Figs. 2C–E , 3C, D , 4C–E , 5C, E, F ). Females of N. depressum n. comb. may be distinguished from those of N. hesperia by the epigynum, which possesses a doubly-lobed concave anterior hood versus the single hood in N. hesperia . Moreover, the epigynum in N. depressum n. comb. possesses anteriorly-directed spermathecae that are lateral to the wide median lobe whereas in N. hesperia , these spermathecae are centrally-directed underneath the thinner part of the median lobe ( Figs. 2G, H , 3F, G , 4G, H , 5G, H ).

Description. Male (MCZ 21047, holotype; Figs. 4A–E , 5A–F ). Small to medium-sized (1.38–2.42) erigonines with carapace pale yellow to dark brown with black around eyes; legs slightly lighter in color than carapace; abdomen mottled light gray to concolorous black ( Fig 4A ). Eyes, teeth, pits, anterior and posterior sulci, venter, and spinnerets typical of genus. Clypeus with slight anterior bulge and many microsetae ( Figs. 1 , 5B ). Leg lengths, macrosetae, and claw teeth typical of genus. Metatarsi I–III each with single trichobothrium; metatarsus IV lacking trichobothrium; tibia I–III each with single trichobothrium; tibia IV with 1–4 trichobothria. Pedipalp with large medial radical apophysis that, when viewed ventrally, is straight and shifted prolaterally of center ( Figs. 4B , 5A ). Distal portion of embolus projects ventrally retrolateral of radical apophysis though much of embolus is hidden behind tegulum. Protegulum extends anteriorly adjacent to and past tip of radical apophysis ( Figs. 4B, E , 5A ). Paracymbium rounded at tip ( Figs. 4B, E , 5A ).

Female (MM 6D15, Indiana: Johnson Co.; Figs. 4F–H , 5G, H ). Coloration of carapace, abdomen, and legs as in male. Females lack sulci and pits ( Fig. 4F ). Clypeus not bulged and lacking large numbers of clypeal hairs as in male. Eyes, teeth, venter, spinnerets, chelicerae, leg lengths, macrosetae, trichobothria, and claw teeth as in male. Epigynum with single concave anterior hood and dual, ventrally-visible spermathecae. Median plate wide posteriorly and narrows anteriorly ( Figs. 4G , 5G ). Spermathecae directed centrally, underneath thinner part of median plate. Dual copulatory openings exist medially near narrowing of median plate. Fertilization and copulatory ducts coiled laterally to spermathecae ( Figs. 4H , 5H ).

Measurements. Male: (n=27): Total length, 1.38–2.42 (mean=1.98); carapace length, 0.73–1.15 (mean=0.96); carapace width, 0.57–0.93 (mean=0.74); femur I length (n=26), 0.47–0.86 (mean=0.69); (n=2): TmI (n=28), 0.52– 0.82 (mean = 0.74). Female: (n=40): Total length, 1.54–2.83 (mean=2.18); carapace length, 0.7–1.21 (mean=0.98); carapace width, 0.55–0.96, (mean=0.75); femur I length (n=39), 0.44–0.92 (mean=0.71); TmI (n=35), 0.63–0.85 (mean = 0.75).

Variation. Males showed some variation in their palpal tibial apophyses, especially in the number of distal small teeth present and the size and shape of the proximal keel ( Fig. 8 ). Males also showed some variance in the shape (curvature and length) of their sulci and their embolic division ( Fig. 9 ). Little to no morphological variation observed in the females.

Distribution. Known from British Columbia east to Nova Scotia and south to South Carolina. Likely distributed throughout North America ( Fig. 7 ).

Natural history. Adults have been collected year round from a variety of habitats, including on the trunks, underneath the bark, and lichen on trees, on buildings, within leaf litter in mature forests, in wetlands, in meadows, and sand pits. It has been found associated with a variety of trees, including aspen, poplar, white spruce, American elm, crab apple, birch, oak, maple, and jack pine.

Other material examined. CANADA: New Brunswick: 1 female, Kent County, Kouchibouguac National Park , in bird nest in jack pine, 10 August 1977, E.E. Lindquist ( CNC 1044595 ) ; 1 male, Madawaska County, Green River , 48.3 km. N. Edmunston, 31 July 1968, T. R. Renault ( CNC, 1030077) ; Nova Scotia: 1 male, Kings County, Kentville , 22 March 1957, unknown collector ( CNC, 1030080) ; Quebec: 1 male, Les Collines-de-l’Outaouais Regional County, Gatineau Park , 1 April 2009, L. Masner ( CNC, 1044584) ; 1 male, Les Collines-de-l’Outaouais, 26 June 1992, L. Lesage ( PP, LL92-51 ) ; 1 male, Eeyou Istchee James Bay Territory, 119 km. N of LaSarre, 13–20 June 1997, P. Paquin and N. Dupérré ( PP, 6677) ; Ontario: 1 female, Thunder Bay District, Pukaskwa National Park in Heron Bay near park office, 2 June 2013, C. Harpur ( UG, BIOUG09421 - D04 ) ; 1 male, Lanark County, Smith Falls Collegiate Institute , 8 May 2015, V. Currie ( UG, BIOUG21961 - E03 ) ; Manitoba: 1 male, Treaty 2 Territory, Riding Mountain National Park , Wasagaming , 21 August 1979, J. & M. Redner ( CNC, 1030079) ; 1 female, Division No. 5, Turtle Mountain Provincial Park, Max Lake , 17 June - 21 August 1988, S. & J. Peck ( CNC, 1044586) ; Saskatchewan: 1 female, Division No. 1, Moose Mountain Provincial Park, Moose Mountain , 4 June 1973, J. Redner & C. Starr ( CNC, 1044591) ; 1 female, Division No. 15, Anglin Lake (53.73, -105.93), 4 May 1997, D. J. Buckle ( DB, 7896) ; 1 female, Prince Albert National Park, Hwy 263, 17 May 2012, R. Thompson ( UG, BIOUG03561 - E11 ) ; 1 female, Division No. 11, 12 mi. SW Saskatoon, 24 March 1973, D. J. Buckle ( DB, 7900) ; 1 female, 30 April 1973, ( DB, 7901) ; 1 male, Saskatoon (52.117, -106.63), 3 October 1980, D. J. Buckle ( DB, 7897) ; 7 males, 3 females, 21 April 1993, ( DB, 7898) ; 1 male, 12 May 1996, ( DB, 7899) ; Alberta: 1 female, Clear Hills County (56.77, -118.37), 30 May 2006, J. Pinzon ( DB, 7892) ; 1 female, 2 August 2008, ( DB, 7893) ; 1 female, summer 2008, ( DB, 7894) ; 1 female, 25 July 2008, ( DB, 7895) ; 1 male, Lamont, Elk Island National Park, Wood Bison Trail , 2 July 2012, unknown collector ( UG, BIOUG05837 - E08 ) ; 1 male, Hayburger Trail , 30 June 2012, unknown collector ( UG, BIOUG12570 - H05 ) ; 1 female, Woodlands County, Whitecourt , 11 April 2012, J. Sloan ( UG, BIOUG20050 - G08 ) ; 1 male, Yellowhead County, Edson, Edson Rest Stop , 5 August 2010, G. Blagoev ( UG, BIOUG00511 - C04 ) ; British Columbia: 1 female, Capital Regional District, Langford, Goldstream Provincial Park , 2 January 1975, A. P. Mackie ( CNC, 1044596) ; U. S. A.: Maine: 1 male, Washington County, Township 18 MD BPP, Field 18-HC-2A, 5 May 2003, D. T. Jennings ( MCZ, 118484) ; 1 male, Aroostook County, New Limerick , 9 May 2008, F. M. Skinner ( MCZ, 140959) ; 1 female, York Co., Wells , GCampground, 1 May 2007, W. Urquhart ( MD) ; New Hampshire: 1 male, Grafton County, Grafton, Mt. Moosilauke , 4 July 1912, J. H. Emerton ( MCZ, 154467) ; Massachusetts: 1 male, Middlesex County, Pepperell , October 1978, H. W. Levi, L. R. Levi, and F. Levi ( MCZ, 47522) ; North Carolina: 1 male, Jackson County, Cullowhee, Cane Creek , 7 January 1984, R. G. Bennett ( CNC, 1030078) ; Indiana: 3 males, 18 females, Johnson County, Blossom Hollow Nature Preserve , litter sift, 15 December 2017, M. A. Milne ( MM, 6 D 15) ; 7 males, 13 females, sticky traps on Fagus grandifolia , 22 February - 15 March 2020, M. A. Milne, C. Wimmersberger, E. Mullins, and C. Venable ( MM, 12 A 8) ; South Carolina: 1 male, Aiken Co., Jackson, 110 Cowden St. , 24 November 1993, M. Draney and V. L. Medland ( MD) .

Figures

FIGURE 1. SEM micrograph of the lateral view of the carapace of Neodietrichia depressum n. comb. (MM 6D15, Indiana, Johnson Co.). Arrow indicates substance filling pit. S, sulci.

FIGURE 2. Photographs of Neodietrichia hesperia (Male: MCZ 140958, Maine: Washington Co.; Female: RB, Ohio: Vinton Co.). A, Male habitus; B, male left palp, ventral view; C, male left palp, prolateral view; D, male left palp, dorsal view; E, male left palp, retrolateral view; F, female habitus; G, epigynum, ventral view; H, epigynum, cleared dorsal view. Scale bars represent 0.25mm.

FIGURE 3. Illustrations of Neodietrichia hesperia (Male: AMNH_IZC 00328051, holotype; Female: RB, Ohio: Vinton Co.). A, Holotype male left palp, ventral view; B, male carapace, lateral view; C, holotype male left palpal tibial apophysis, retrolateral view; D, holotype male left palp, dorsal view; E, holotype male left palpal embolic division, prolateral view; F, epigynum, ventral view; G, epigynum, cleared dorsal view. R, radix; E, embolus; Pt, protegulum; RA, radical apophysis; T, tegulum; Pc, paracymbium; Su, sulci; H, hood; S, spermathecae; CO, copulatory openings; MP, median plate; CD, copulation ducts; FD, fertilization ducts.

FIGURE 4. Photographs of Neodietrichia depressum n. comb. (MM 6D15, Indiana, Johnson Co.). A, Male habitus; B, male left palp, ventral view; C, male left palp, prolateral view; D, male left palp, dorsal view; E, male left palp, retrolateral view; F, female habitus; G, epigynum, ventral view; H, epigynum, cleared dorsal view. Scale bars represent 0.25mm.

FIGURE 5. Illustrations of Neodietrichia depressum n. comb. (MM 6D15, Indiana, Johnson Co.). A, Male left palp, ventral view; B, male carapace, lateral view; C, male left palpal tibial apophysis, retrolateral view; D, male left palpal embolic division, prolateral view; E, male left palpal tibial apophysis, dorsal view; F, same, variation; G, epigynum, ventral view; H, epigynum, cleared dorsal view. R, radix; E, embolus; Pt, protegulum; RA, radical apophysis; T, tegulum; P, paracymbium; TbA, tibial apophysis; Su, sulci; K, keel; H, hood; S, spermathecae; CO, copulatory openings; MP, median plate; CD, copulation ducts; FD, fertilization ducts.

FIGURE 7. All known collection locations of Neodietrichia. Open circles represent Neodietrichia hesperia. Filled circles represent Neodietrichia depressum n. comb.

FIGURE 8. Variation in male palpal tibial apophyses in Neodietrichia depressum n. comb. Illustrations represent retrolateral views. The number of spines on the tibial apophysis is variable and does not appear to be geographically correlated.

FIGURE 9. Variation in male palpal embolic divisions in Neodietrichia depressum n. comb. TP, tailpiece; R, radix; E, embolus; RA, radical apophysis.