Stomotheca is the term applied to the feeding apparatus in front of the mouth of

harvestmen The Opiliones (formerly Phalangida) are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. , over 6,650 species of harvestmen have been discovered worldwide, although the total number of ext ...

, and sometimes the related

scorpion Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always end ...

s. Usually it consists of the ''epistome'' ( labrum), two pairs of ''coxapophyses'' (endites,

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

ry lobes) and often a '' labium''. (2007): Morphology and Functional Anatomy. In: Pinto-da-Rocha ''et al.'' 2007: 23ff The ''epistome'' is a projection that forms the anterior wall of the stomotheca. Its upper side is hardened and divided by a transverse invagination ( sulcus). The part nearer the groove is sometimes called clypeus, the other one labrum. The area around the mouth is soft and flexible, often with a distal lobe. On the sides, the walls around the mouth are fused to the medial surfaces of the pedipalpal coxae, and a transverse muscle attaches to the inner surfaces of the epistomal walls. ''Coxapophyses'' are extensions from the pedipalps and first pair of legs. While hardened at the base, they end in large soft pads that work as lips. It some species there is a narrow canal (pseudotrachea) on the posterior surface of the pedipalpal coxapophysis, possibly conducting fluids into the digestive tract.

Salivary gland The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands (parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary gla ...

s lead into the preoral chamber from both pairs of coxapophyses. While most harvestmen have coxapophyses on the second pair of legs as well, these do not end in pad-like structures and are reduced in many groups. Where they are fully developed, they probably aid in food intake. Similar lobular structures are sometimes found on the two latter pairs of legs as well, but their function is unknown. The ''labium'', when present, is a flattened plate derived from the

somite The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryonic stage of somitogenesis, along the head-to-tail axis in segmented animals. In vertebrates, somites subdivide in ...

of the first walking leg. While large in many

Eupnoi The Eupnoi are a suborder of harvestmen, with more than 200 genera, and about 1,700 described species. They consist of two superfamilies, the Phalangioidea with many long-legged species common to northern temperate regions, and the small group C ...

and

Dyspnoi Dyspnoi is a suborder of harvestmen, currently comprising 43 extant genera and 356 extant species, although more species are expected to be described in the future. The eight families are currently grouped into three superfamilies: the Acropsopil ...

, it is small in most

Laniatores Laniatores is the largest suborder of the arachnid order Opiliones with over 4,000 described species worldwide. The majority of the species are highly dependent on humid environments and usually correlated with tropical and temperate forest habit ...

and absent in

Cyphophthalmi Cyphophthalmi is a suborder of harvestmen, colloquially known as mite harvestmen. Cyphophthalmi comprises 36 genera, and more than two hundred described species. The six families are currently grouped into three infraorders: the Boreophthalmi, Sc ...

. The term ''stomotheca'' is derived from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''stoma'' "mouth" and ''theca'' "case, box".

Footnotes

References

* (eds.) (2007): Harvestmen - The Biology of Opiliones. ''Harvard University Press'' {{ISBN, 0-674-02343-9 Harvestmen Arachnid anatomy