Apophysis (plural apophyses): An outgrowth or process changing the general shape of a body part, particularly the appendages; often used in describing the male pedipalp:[2] see retrolateral tibial apophysis
Atrium (plural atria): An internal chamber at the entrance to the copulation duct in female haplogyne spiders[2]
Book lungs: Respiratory organs on the ventral side (underside) of the abdomen, in front of the epigastric furrow, opening through narrow slits;[3] see also Book lungs
Calamistrum (plural calamistra): Modified setae (bristles) on the metatarsus of the fourth leg of spiders with a cribellum, arranged in one or more rows or in an oval shape, used to comb silk produced by the cribellum; see also Calamistrum
Cephalothorax or prosoma: One of the two main body parts (tagmata), located towards the anterior end, composed of the head (cephalic region or caput) and the thorax (thoracic region), the two regions being separated by the cervical groove; covered by the carapace and bearing the eyes, legs, pedipalps and mouthparts[3]
Cervical groove: A shallow U-shaped groove, separating the cephalic and thoracic regions of the carapace[3]
Chelate: A description of a chelicera where the fang closes against a tooth-like process[1]
Chelicera (plural chelicerae): One of two appendages at the front of the carapace, made up of basal portion, the paturon, and the fang;[5] sometimes called the jaw; see also Chelicerae
Cheliceral furrow: A shallow groove on the basal portion of a chelicera accommodating the fang, usually having teeth on its margins[6]
Cheliceral tooth: A tooth-like extension on the margin of the cheliceral furrow[7]
Chilum: A small hardened plate (sclerite) at the base of the chelicerae, under the clypeus[7]
Claw tuft: A dense group of hairs or bristles (setae) underneath the paired tarsal claws, usually well developed in hunting spiders[6]
The clypeus of this jumping spider is covered with red scales.
Clypeus: The area of the carapace between the anterior (frontmost) eyes and the anterior edge of the carapace[6]
Colulus: A short protuberance in the middle of the underside of the abdomen in front of the spinnerets, considered to be a modification of the cribellum[6]
Copulatory duct: An internal tube (duct) from the copulatory opening through which sperm enters the female; separate from the duct through which fertilized eggs pass in entelegyne spiders[8]
Copulatory opening: An opening in the ventral abdomen of female spiders; in entelegyne spiders, a double opening in the epigyne through which the embolus is inserted; in haplogyne spiders, a single opening through which male palpal bulb is inserted[6]
Cribellum: A sieve-like plate in front of the spinnerets, used in conjunction with the calamistrum; spiders with a cribellum are called cribellate, those without ecribellate;[4] see also Cribellum
Dorsum: The upper (dorsal) portion or surface of the body or abdomen; the adjective dorsal may be applied to the upper portion or surface of any part of the body; see ventrum
Endosternite: An internal hardened plate (sclerite)[9]
Entelegyne: A spider whose female has an epigyne and separate ducts leading to spermathecae for sperm storage and to the uterus for fertilization,[6] creating a "flow-through" system; see haplogyne; see also Entelegynae
Basic arrangement of spider eyes, viewed from aboveArrangement of eyes in most Salticidae, viewed from above
Epigastric furrow or epigastric fold: A transverse slit towards the front (anterior) of underside of the abdomen; the front pair of book lungs open at the edge of this furrow as do the genital openings (gonopores)[10]
Epigyne or epigynum (plural epigynes): A hardened plate on the underside of the female abdomen in which the copulatory openings are located; only fully developed in mature females of entelegyne spiders;[6] see also Epigyne
Eyes: The basic number of eyes is eight, typically arranged in two rows (e.g. as in Gnaphosidae); the front row are the anterior eyes, the row behind the posterior eyes; the four eyes to the edges are the lateral eyes, the four eyes in the centre the median eyes; the anterior median eyes are called the main eyes or direct eyes, while the other eyes are called the secondary eyes or indirect eyes; the number of eyes, their sizes and arrangement varies widely and is characteristic of spider families; see main eye, secondary eye
F
Fang: The final hinged part of the chelicera, normally folded down into a groove in the basal part of the chelicera; venom is injected via an opening near the tip of the fang[11]
Larinioides cornutus spider showing folium on abdomen
Folium: A broad leaf-like marking along the medial line of the top of the abdomen
Fossa (plural fossae): A pit or depression, typically in the epigyne[12]
Fovea (also called thoracic furrow or dorsal groove): A depression or pit in the centre of the carapace of a spider marking an inward projection of the exoskeleton to which stomach muscles are attached[13][14]
Gonopore: The genital opening; located in the epigastric furrow; the opening of the duct from the uterus in females and from the testes in males;[9] see also Gonopore
H
Haematodocha (also spelled hematodocha): see palpal bulb
Haplogyne: A spider whose female lacks an epigyne and in which the same ducts are used to transport sperm to the uterus and to the spermathecae;[15] see entelegyne; see also Haplogynae
Heart mark: A narrow marking along the top of the abdomen roughly corresponding to the location of the heart
L
Labio-sternum mound: A mound separating the labium from the sternum, found in some tarantulas, where it can be a diagnostic feature[16]
Lateral (applied to appendages): Viewed from above or below, the sides of the leg or pedipalp, i.e. the surfaces parallel to the line of sight; see prolateral, retrolateral
Laterigrade: With legs directed to the side, hence appearing like and moving like a crab;[17] see prograde
Leg formula: The legs are numbered from the front from I to IV; the relative length of the legs can be represented by four numbers from the longest to the shortest; e.g. 1423 = first leg (leg I) is longest and third leg (leg III) is shortest[17]
Main eye: One of the two anterior median eyes (AME) that have the light-detecting units (rhabdomeres) pointing towards the source; particularly enlarged in the families Salticidae and Thomisidae;[18] see secondary eye, eyes
Mastidion (plural mastidia): A projection or bump on the chelicerae (not to be confused with teeth)
Maxilla (plural maxillae; also called endite or gnathocoxa): Modified coxa of the pedipalp, used in feeding;[14][6] not the structure called by this name in other arthropods, for which see Maxilla (arthropod mouthpart)
Operculum or branchial operculum (plural opercula): One of the plates on the ventral surface of the abdomen, just in front of the epigastric furrow, covering the book lungs, often pale, yellow or orange in colour; two pairs in Mygalomorphae, one pair in other spiders[1]
Highly simplified and stylized diagram of the main parts of an inflated palpal bulb, based loosely on Coddington (1990);[19] hardened parts shown darker, membranous parts shown lighter
Palpal bulb (also called bulbus, palpal organ, genital bulb): The copulatory organ of the male spider, carried on the modified last segment of the pedipalp, used to transfer sperm to the female;[20] see also Palpal bulb
Conductor: A part of the palpal bulb that accompanies and supports the embolus[6]
Embolus: The final part of the palpal bulb containing the end of the sperm duct, usually thin, sharp-tipped and strongly hardened (sclerotized)[6]
Haematodocha (plural haematodochae): A membranous, inflatable part of the palpal bulb[10]
Median apophysis: A projection (apophysis) of the palpal bulb, below the conductor
Subtegulum: A hardened part of the palpal bulb nearer its base than the tegulum
Tegulum: The main hardened part of the palpal bulb
Pedipalp (plural pedipalps or pedipalpi; also called just palp): The second appendage of the cephalothorax in front of the first leg; bears the palpal bulb in male spiders;[10] see segments, see also Pedipalp
Plumose: Used to describe hairs (setae) having outgrowths or appendages on two sides, giving a feather-like appearance; the appendages vary in number, size and arrangement[23]
Postembryo (also called larva): The stage of development between hatching from the egg and first molting
Procurved: Used to describe a structure which is curved in such a way that the outer edges are in front of the central part;[22] opposite recurved
Prolateral: Viewed from above or below, the side of a leg or pedipalp nearest the mouth, i.e. the side facing forward; opposite retrolateral (includes diagram)
Rastellum (plural rastella): An often rake-like structure at end of the chelicera in mygalomorph spiders; used in burrowing[22]
Rebordered: Having a thickened edge (i.e. border)[24] (more rarely seen as reborded, from the French rebordé, e.g. in Levy (1984)[25]); particularly used of the labium
Terminology of appendage surfaces
Receptaculum (plural receptacula): see spermatheca
Recurved: Used to describe a structure which is curved in such a way that the outer edges are behind the central part;[22] opposite procurved
Retrolateral: Viewed from above or below, the side of a leg or pedipalp furthest from the mouth, i.e. the side facing backwards; opposite prolateral
Retrolateral tibial apophysis: A backward-facing projection on the tibia of the male pedipalp; distinguishing feature of the RTA clade
Retromarginal: The side of the cheliceral furrow facing backward (towards the posterior end of the spider); particularly used for describing teeth; opposite promarginal
Scape: An elongated process or appendage of some epigyne[26]
Sclerite: A single hardened (sclerotized) part of the external covering (tegument, exoskeleton)[24]
Scopula (plural scopulae): A brush of hairs (setae); called a claw tuft when on the end of the foot (tarsus), where it improves adhesion[22][27]
Scutum (plural scuta): A hardened (sclerotized) plate on the abdomen of some spiders
Secondary eye: An eye belonging to the three pairs – anterior lateral eyes (ALE), posterior median eyes (PME) and posterior lateral eyes (PLE) – that are primarily movement detectors and have the light-detecting units (rhabdomeres) pointing away from the source;[28] see main eye, eyes
Pedipalp and leg of a female spider from the underside; the coxa of the pedipalp is heavily modified to form the maxilla
Coxa (plural coxae): First leg segment, between body and trochanter; the coxa of the pedipalp is heavily modified to form the maxilla or endite
Trochanter: Second leg segment, between coxa and femur
Femur (plural femora): Third leg segment, between trochanter and patella
Patella (plural patellae): Fourth leg segment, between femur and tibia
Tibia (plural tibiae): Fifth leg segment, between patella and metatarsus
Metatarsus (plural metatarsi; also called basitarsus): Sixth leg segment, between tibia and tarsus; absent in the pedipalp
Tarsus (plural tarsi; also called telotarsus): Seventh (last) leg segment, after the metatarsus
Serrula: A row of tiny teeth along the edge of the maxilla
Seta (plural setae): A bristle;[22] spiders have a variety of hair-like structures of increasing size that are referred to as hairs, bristles (setae) or spines[29]
Sigillum (plural sigilla): A circular indentation on the outside of the spider, showing where an internal muscle is attached;[30] particularly on the sternum in some Mygalomorphae and on the dorsum in some Araneomorphae[22]
Sperm duct: A duct in the male palpal bulb used to store sperm[22]
Spermatheca (plural spermathecae; also called receptulacum, receptulacum seminis): A structure in the abdomen of female spiders used to store sperm after insemination and before fertilization;[22] see also Spermatheca
Spigot: A small pointed or cylindrical structure at the tip of a spinneret from which silk emerges[22]
Spine: A pointed, rigid structure on body and legs, usually with a basal joint;[31] spiders have a variety of hair-like structures of increasing size that are referred to as hairs, bristles (setae) or spines[29]
Spinneret: An appendage borne on the abdomen, typically one of six arranged in three pairs: anterior (anterior median, AMS), median (posterior median, PMS) and posterior (posterior lateral, PLS); silk emerges from small spigots on the spinnerets;[31][1] see also Spinneret
Sternum: The lower (ventral) portion of the cephalothorax
Stridulating organ: A series of thin ridges on a hardened part of the body; rubbing this with a matching series of short, stiff bristles (setae) elsewhere on the body creates a sound[31]
Subadult: A spider in the last stage of development (penultimate instar) before becoming a sexually mature adult
Tapetum (plural tapeta): A light-reflecting layer in a secondary eye making the eye appear pale[31]
Tarsal claw (claw): One of a set of claws at the tip of the tarsus; there may be a single pair, often concealed in a claw tuft, or an additional third central claw, much smaller than the other two[31]
Tarsal organ: a small pit, usually spherical and on the dorsal surface of each tarsus, believed to respond to humidity[32]
Trachea (plural tracheae): A thin hardened internal tube, part of the respiratory system in many araneomorph spiders; opens on the underside of the abdomen via a tracheal spiracle;[33] see Trachea § Invertebrates
Trichobothrium (plural trichobothria): A slender hair-like structure of variable length on the legs and pedipalps, arising from a special socket; used to detect air movements, including sounds;[34] see seta, spine
Venter (or ventrum): The lower (ventral) portion or surface of the body or abdomen; the adjective ventral may be applied to the lower portion or surface of any part of the body; see dorsum
^Coddington, J.A. (1990). "Ontogeny and homology in the male palpus of orb-weaving spiders and their relatives, with comments on phylogeny (Araneoclada: Araneoidea, Deinopoidea)". Smithsonian Contributions to Zoology. 496 (496): 1–52. doi:10.5479/si.00810282.496. Figs 5–8{{citation}}: CS1 maint: postscript (link)
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