Artema Walckenaer, 1837

Artema Walckenaer, 1837: 656; type species: Artema atlanta (by subsequent monotypy).

Coroia González-Sponga, 2005: 102; type species: Coroia magna González-Sponga, 2005; synonymized by Huber et al. 2014: 416.

Diagnosis

Artema is easily distinguished from other pholcids by its large body and strong legs (body length 5.5– 9.5 mm; leg span up to 15 cm; tibia 1 L/d: 34–42); also by distinctive pattern on globose and high abdomen (dark dots dorsally, arranged in stripes from dorsal to lateral, sometimes absent; Figs 3–5, 51– 53); by male pedipalp with its unique bulbal processes and short but massive procursus with proximal dorsal process (dp: Fig. 89) and weakly developed ventral pocket (vp: Fig. 89); by armature of male chelicerae (frontal row of cone-shaped hairs on each side, situated on elevated processes or ridges; Figs 23, 44); and by pair of low to high projections in front of large anterior epigynal plate (AEP: Fig. 15).

Description

Male

MEASUREMENTS. Total body length 5.5–9.5, carapace width 3.0–4.3. Leg 1: 39–61, tibia 1: 6.0–22.2; tibia 1 L/d: 34–42. Distance PME–PME 150–220 μm, diameter PME 170–230 μm, distance PME–ALE 90–140 μm, distance AME–AME 30–60 μm, diameter AME 180–210 μm.

COLOR. In general variable, even within species. Carapace pale to light brown, sometimes with brown radial marks, with light to dark brown median band (as in Figs 35, 76, 121). Clypeus with wide light brown band. Legs pale yellow to ochre with dark rings on femora subdistally, patellae + tibiae proximally, and tibiae subdistally; tips of femora and tibiae whitish. Abdomen pale gray to light brown, usually with dark dots dorsally, arranged in distinctive stripes from dorsal to lateral side of abdomen (as in Fig. 4); sometimes without any pattern (as in Figs 51–53).

BODY. Ocular area slightly elevated. Carapace with median pit and distinct posterior furrow. Clypeus unmodified. Sternum wider than long. Chelicerae with frontal row of ~16–25 modified (cone-shaped; Figs 34, 68–69) hairs on pair of elevated processes or ridges, variable in shape among species; lateral field of stridulatory ridges on chelicerae present or absent (variable even within species; Figs 31, 70, 118). Abdomen globose and high (as in Fig. 5). Gonopore with 4–7 epiandrous spigots (Fig. 63). Anterior lateral spinnerets with one extremely widened, one long pointed, and six cylindrically shaped spigots each (Figs 26, 28, 74); PMS with two spigots each (Figs 25, 75); PLS without spigots.

PALPS. Coxa unmodified. Trochanter with short ventral projection (as in Figs 77–79). Femur with short, somewhat pointed retrolateral process proximally (as in Figs 180–182); ventral membranous area proximally bordered on both sides by sclerotized ridges. Patella very short. Procursus with proximal dorsal process and weakly developed ventral pocket (Fig. 89); with brush-like distal modifications of filiform cuticular projections (cf. Huber 2000: fig. 48). Bulb with several distinctive processes (here called ‘processes a–e’; processes c–e sometimes absent) and membranous embolus arising from base of process a (e.g., Figs 19–20, 27, 39–40, 64).

LEGS. Without spines; with long curved hairs, especially on tibiae and metatarsi; retrolateral trichobothrium on tibia 1 at 8–10%; prolateral trichobothrium present on all tibiae; tibia 2/ tibia 4 length usually <1.0, only in Artema doriae Thorell, 1881 >1.0; pseudosegmentation of tarsi not visible; tarsi 4 with distinct comb-hairs of the plesiomorphic, complex ‘ Belisana -type’ (Huber & Fleckenstein 2008).

Female

In general similar to male, but legs shorter (tibia 1: 5.3–16.5), and stridulatory files laterally on chelicerae always present and distinct (Figs 30, 71, 154). Epigynal plate usually consisting of two sclerotized lateral areas (Fig. 15), sometimes with dark median sclerite anteriorly (Figs 48, 103, 138; variably large and variably distinct); with distinctive pair of anterior epigynal projections (AEP: Figs 15, 86, 103, 138). Cleared female epigyna are shown in dorsal views (Figs 201–207) and in posterior dorsal views (Figs 208–214); the diagnostic value of the female internal genitalia in Artema is unclear so we do not put further emphasis on this in the species descriptions.

Natural history

Like most other non-forest pholcids, representatives of the genus Artema live in dark and sheltered habitats such as caves, holes and crevices, and spaces under large rocks. However, they also occur in man-made habitats like bunkers, buildings and basements, and under concrete bridges (cf. Huber & Kwapong 2013). In a large cave survey we conducted in Israel (Aharon 2016), we found most individuals of A. nephilit sp. nov. in caves in a very hot and arid zone with low mean annual precipitation (50–150 mm). Other species in the genus were also collected partly from very dry regions and arid deserts with less than 50 mm of annual precipitation, e.g., A. doriae at the Arava Valley, Israel, and Artema sp. b at El Goléa in the Algerian Sahara.

The web is made of non-sticky silk and often appears irregular. This may partly be due to the fact that webs accumulate over time to form huge masses of old silk full of exuviae, while the spider occupies only a small but more regular slightly domed sheet within this mass (Fig. 6). As usual in pholcids, females carry their egg sacs, but the silk cover is much denser than in most other pholcid genera observed (Fig. 3). For further data on natural history, see under A. nephilit sp. nov. description below.

Distribution

The type species A. atlanta Walckenaer, 1837 has a worldwide distribution, presumably as a result of human-aided transport (Fig. 2). All other species are restricted to the Old World, ranging from the African Sahel to Central and South Asia (Fig. 1).

Relationships

Together with eight other genera, Artema is a member of the subfamily Arteminae Simon, 1893, which currently contains 99 nominal species. Other genera included are: Wugigarra Huber, 2001; Trichocyclus Simon, 1908 and Holocneminus Berland, 1942 in Australia and Southeast Asia; Chisosa Huber, 2000; Aucana Huber, 2000 and Physocyclus Simon, 1893 in the New World, and the monotypic genera Tibetia Zhang, Zhu & Song, 2006 and Nita Huber & El-Hennawy, 2007 in Central Asia and northeastern Africa (Huber 2011 b, 2016). The subfamily is characterized by two (functionally closely related) morphological synapomorphies, which constitute a pair of distinctive structures on the procursus: a dorsal process (dp: Fig. 89) and a ventral pocket (vp: Fig. 89) (Huber & Eberhard 1997; Huber 2011b). Previous molecular studies supported the subfamily (e.g., Dimitrov et al. 2013), but current analyses of a much larger sample of taxa are ambiguous with respect to the positon of Artema (J. Eberle, A. Valdez-Mondragón, D. Dimitrov, B.A. Huber, unpublished data). Morphological data suggest that Artema is ‘basal’ within Arteminae, i.e., sister to all other genera. This is supported by the fact that all other Arteminae genera lack epiandrous spigots (Huber 2016). Internal relationships among species remain largely obscure. Some of the similarities described below (e.g., between A. transcaspica and A. doriae) are likely synapomorphic, while others (e.g., among A. nephilit sp. nov., A. bunkpurugu, A. atlanta and A. magna) may turn out to be homoplastic.

Composition

As construed here, the genus Artema includes eight nominal species: the type species A. atlanta Walckenaer, 1837; A. bunkpurugu Huber & Kwapong, 2013; A. kochi Kulczyński, 1901 (revalidated); A. nephilit sp. nov.; A. doriae Thorell, 1881; A. transcaspica Spassky, 1934; A. magna Roewer, 1960; and the dubious A. ziaretana (Roewer, 1960) (which is based on a single juvenile specimen and might be a synonym of A. magna; see Notes under redescription of A. magna).

Based on known distribution patterns (no small-scale endemism), we do not expect a significantly higher species richness. However, some of our taxonomic decisions may prove wrong as more material becomes available and this may affect species numbers. In addition, specimens from northern Africa (Algeria, Sudan), the Arabian Peninsula (Yemen, Oman), the Middle East (Iran), and South Asia (Pakistan, India) that we do not formally describe may all represent additional species.

Identification key

Males

1. Genital bulb without process c (Figs 81, 175) ……………………………………………………2

– Genital bulb with process c (Figs 20, 40) ………………………………………………………3

2. Genital bulb with bulbal process b flattened, rectangular distally (Fig. 81); cheliceral processes strongly projecting proximally with frontal rows of modified hairs (Fig. 83); with several coneshaped, sclerotized processes situated frontally near median line (arrows in Figs 83, 85) ……… ………………………………… ……………………………………… Artema kochi Kulczyński, 1901

– Genital bulb with bulbal process b rather pointed (Fig. 175); cheliceral processes not strongly projecting proximally and without sclerotized processes near median line (Figs 177–178) …… ………………………………………………………………………………… Artema sp.b(Algeria)

3. Genital bulb process c curved and pointing towards prolateral (Figs 40, 95) …………………4

– Genital bulb process c different (either membranous and pointing towards process b, or with sclerotized ridge projecting perpendicular to process b and with small teeth prolaterally; Huber & Kwapong 2013: fig. 58; Figs 20, 27, 29) …………………………………………………8

4. Genital bulb without process d (Fig. 39) or with low rounded projection on ventral side of bulb (Fig. 159). Cheliceral process with median projection (Figs 43–44, 164) ………………5

– Genital bulb with distinct process d (Figs 94, 125). Cheliceral process without median projection (Figs 98, 129, 192–194) ……………………………………………………………………………6

5. Genital bulb without process d (Fig. 39). Each chelicera with frontal row of about 20 modified hairs that splits distally, with outer branch ending at tip of process, inner branch ending at tip of median projection (Fig. 44) ………………………………………… Artema nephilit sp. nov.

– Genital bulb process d indistinct, low rounded projection on ventral side of bulb (Fig. 159). Chelicerae modified hairs on median projection not linked (by row of hairs) to main modified hairs ridge (as in A. nephilit sp. nov.) (Fig. 163) …………………… Artema magna Roewer, 1960

6. Chelicerae in lateral view without or with very indistinct ridge or process above modified hairs (Figs 128, 131–133) …………………………………………… Artema transcaspica Spassky, 1934

– Chelicerae in lateral view with distinct ridge or process above modified hairs (Figs 100–102, 186– 191) …………………………………………………………………………………………………7

7. Chelicerae in lateral view with small ridge or process above modified hairs (Figs 100–102) ……… ………………………………………………………………………… Artema doriae Thorell, 1881

– Chelicerae in lateral view with robust ridge or process above modified hairs (Figs 186–191) …… …………………………………………………………… Artema sp. c (India, Pakistan, Iran, Sudan)

8. Genital bulb process c partly membranous and directed towards process b; processes d and e absent. Chelicerae with frontal row of about ten modified hairs in straight line on each side (cf. Huber & Kwapong 2013: figs 59–60) ……………… Artema bunkpurugu Huber & Kwapong, 2013

– Genital bulb process c with sclerotized ridge projecting prolaterally perpendicular to process b, with small teeth prolaterally on round end of process (Figs 20, 27, 29); processes d and e present (both low and rounded) (Fig. 19). Chelicerae with frontal rows of about 20 modified hairs each in s-shaped pattern (Fig. 24) …………………………………… Artema atlanta Walckenaer, 1837

Females

1. Anterior epigynal projections (AEP) sclerotized and elongated (Fig. 86); epigynal plate wide rectangular, with triangular anterior projection between AEP …… Artema kochi Kulczyński, 1901

– Anterior epigynal projections (AEP) not or only weakly sclerotized and not elongated; epigynal plate different ………………………………………………………………………………………2

2. Epigynal plate rectangular, without dark median sclerite and without prominent pale median area (Fig. 170) ……………………………………………………………… Artema sp. a (Oman)

– Epigynal plate different, either with dark median sclerite and/or prominent pale median area …3

3. Epigynal plate posterior margin strongly indented (Fig. 15) …… Artema atlanta Walckenaer, 1837

– Epigynal plate posterior margin either straight (Figs 46, 105), gently indented (Figs 135, 143) or protruding (Fig. 169) ………………………………………………………………………………4

4. Anterior epigynal projections (AEP) distinctively prominent and pointed (cf. Huber & Kwapong 2013: figs 49, 53–54) ……………… Artema bunkpurugu Huber & Kwapong, 2013

– Anterior epigynal projections (AEP) not prominent and not pointed ……………………………5

5. Epigynal plate ~2.5 × wider than long; median posterior margin distinctively protruding (Fig. 169) ………………………………………………………………………… Artema magna Roewer, 1960

– Epigynal plate less than ~2.5 × wider than long, median posterior margin not protruding ………6

6. Epigynal plate with long dark median sclerite fused at posterior epigynal margin with lateral sclerotized plates (Figs 134–145) …………………………… Artema transcaspica Spassky, 1934

– Epigynal plate long with dark median sclerite not fused at posterior epigynal margin with lateral sclerotized plates (Figs 45–50, 103–114, 195–199) ………………………………………………7

7. Epigynal plate pale median area very inflated and prominent (Figs 195–200) …………………… ………………………………………………………… Artema sp. c (India, Pakistan, Sudan, Iran)

– Epigynal plate pale median area slightly inflated or not inflated …………………………………8

8. Epigynal plate posterior margin almost straight, gently undulating. Pale median area with distinct dark median sclerite ⅓–½ the length of epigynal plate (Figs 45–50) …… Artema nephilit sp. nov.

– Epigynal plate trapezoidal, i.e., wider posteriorly; pale median area slightly inflated posteriorly; dark median sclerite ⅓–⅔ the length of epigynal plate; dark median sclerite not fused at posterior epigynal margin with lateral sclerotized plates (Figs 103–114) … Artema doriae Thorell, 1881