Micaria Westring 1851

Genus Micaria Westring, 1851

Micaria Westring, 1851: 47; Westring 1861: 330; Wunderlich 1980: 238; Platnick & Shadab 1988: 6.

Type species. Aranea fulgens Walckenaer, 1802 by original designation.

Diagnosis. The genus Micaria can be distinguished from other Gnaphosidae genera by the following characteristics: their anterior lateral spinnerets (ALS) are shorter than in other gnaphosids; they have iridescent colouration due to the unique structure of the squamose setae; the piriform gland spigots are small and are basically invisible when retracted (Murphy 2007; Azevedo et al. 2018). They usually have an ant–like appearance, i.e. thin legs, and sometimes constricted abdomen, most visible in males. The carapace and abdomen are decorated with squamose setae, sometimes sicate setae, and legs with feathery setae, aculeate setae and lanceolate setae. Their tarsi are pseu-do–segmented, with two or four rows of scopulate setae ventrally.

Description. Small to medium sized spiders approximately 1.85—5 mm in length; carapace colour ranges from light gold to very dark brown or black (Figs 9–36), decorated with squamose setae responsible for their iridescence; dark striae radiate from middle of carapace towards coxae, sometimes with two white bands on posterior third of carapace that originate close to centre, extending towards posterolateral margins; carapace smooth, decorated with squamose setae (Figs 37, 38), longer than broad, broadest between coxae Iand II (Fig. 39); cephalic area slightly raised, forming “V”–shaped outline towards centre of carapace; posterior margin of carapace variable, either being straight, rounded or indented; fovea absent; 1–3 erect setae present between eye rows; AER usually recurved (Fig. 40), sometimes straight (anterior view); ALE slightly larger than AME; AME closer to ALE than to each other, interdistances between AME variable relative to AME diameter; PER usually procurved in larger species (Fig. 41), slightly recurved in smaller species (Fig. 42); PME closer to PLE than to each other; MOQPW always wider than MOQAW, MOQL less (Fig. 41) or greater (Fig. 42) than MOQPW. Chelicerae smooth in texture (Fig. 43), decorated with short to long plumose setae (Figs 44, 45); paturon with two promarginal teeth and one retromarginal tooth (Fig. 46); endites obliquely slanted towards base of chelicerae (Fig. 47); serrula present (Fig. 48), slightly constricted medially; maxillar hair tufts distinct; labium subtriangular, rounded distally, decorated with few setae. Sternum shield-like, longer than broad, decorated with long, straight, aculeate setae (Fig. 49) and/or squamose setae (Figs 50, 51, 52); anterior margin straight; widest between coxa Iand II. Leg formula 4123, rarely 4312 or 1423; tarsal organ present on distal dorsal margin of tarsi (Fig. 53); slit sensilla present on distal ventral surface of metatarsus and retrolaterally on tarsi (Fig. 54); lyriform organs present (Figs 55–64) on retrolateral margin of patella (position variable); femur of leg Ilaterally flattened, slightly larger than others; preening comb absent; legs decorated with lanceolate (Figs 65–78), or feathery setae (Figs 79–85), chemosensory setae (Fig. 86), trichobothria (Fig. 87) and aculeate setae (Fig. 88). Scopulate setae present on tibia, metatarsus and tarsus (Figs 89, 90). Claw tuft setae present on tarsi (Fig. 91), claw teeth variable. Abdomen oval, usually dark brown to black; sometimes with median constriction (Fig. 92), more prominent in males; in such cases, anterior half of abdomen may be lighter in colour than posterior half; abdominal patterns variable; decorated with squamose setae (Fig. 93), scattered aculeate setae, occasionally sicate (Fig. 94) and elongate squamose setae on anterior half (Fig. 95); venter usually slightly lighter than dorsum, decorated with squamose setae. ALS similar in size to PLS, larger than PMS, with at least one major ampullate gland and one tartipore; males with no piriform gland spigots (Fig. 96) and females with one piriform gland spigot (Fig. 97); ALS with piriform gland spigots similar in size to major ampullate gland spigots, widened shaft, may be invisible when retracted; PMS short, with one major ampullate gland spigot and at least three minor ampullate glands spigots (Figs 98, 99); PLS with two cylindrical glands spigots basally, and two major ampullate glands spigots (Figs 100, 101). Epigyne weakly sclerotised; anteriorhood variable, being either continuous (Fig. 102) or divided in two (Fig. 103); posterior pockets present, their positions variable; copulatory ducts variable, short or elongate, extending medially between spermathecae, originating from the copulatory openings and ending at base of spermathecae; fertilisation ducts short, originating at mesal margin of spermathecae, curved. Male palp with oval tegulum; single median apophysis present, usually hook–shaped (Figs 104, 105); tegular apophysis absent; embolus generally originating prolaterally or medially behind apex of tegulum, curving distally and retrolaterally alongside distal tegular margin; embolus tip short, straight or curved, as long as or slightly longer than median apophysis. Single RTA usually present (Figs 106, 107), exceptions with none or with two apophyses. Two stout spines present on apex of cymbium of several species (Fig. 108).