Adaugammarus Sidorov & Gontcharov & Sharina 2015, gen. nov.
Creators: name: Sidorov, Dmitry A.
name: Gontcharov, Andrey A.
name: Sharina, Svetlana N.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Typhlogammaridae
Adaugammarus

description: Genus Adaugammarus gen. nov.
urn:lsid:zoobank.org:act: C38A81BD-4918-46B0-BD37-4BF7A6669E8F
Type species
Adaugammarus pilosus sp. nov., by monotypy.
Generic diagnosis
Stout and gentle, large-sized species of gammarid-like habitus (sexual dimorphism marked, i.e., some males larger than females, antenna 2, both gnathopods and uropods 1–3 sexually dimorphic). Antenna 1 short, reaching 50% length of body; antenna 2 short, reaching about 50% length of antenna 1, gland cone short. Maxilla 1 inner plate trapezoidal, with 10 plumose setae, outer plate of non-filtration type (?scraper type), with 14 multi-toothed, comb-like spines; palps asymmetric and long. Mandibular palp article 3 with 2 A groups, 2 B groups, 13 D setae and 4 E setae. Gnathopods 1–2 relatively small, with propodus not larger than corresponding coxa; palmar angles of both gnathopods undefined, each bearing a group of notched, strong palmar spines; dactyli with 1 seta along outer margin, nails rather long. Pereopods 5–7 bases distinctly broader in proximal part; inner margin of dactyli of pereopods 3–7 with 1 stiff seta. Urosomites with dorsolateral groups of spines. Pleopods 1–3 with 2 coupling setae (retinacula), each accompanied by 1 seta (2+1). Uropods 1–3 extremely setose, with dense bundles of long swirling setae; uropod 1 exopodite broad and curved; uropod 3 exopodite broad, 1.6× longer than protopodite (in males). Telson with 1 or 2 distal spines per lobe. Coxal gills 2–7 stalked, triangular or sacciforme, largest on gnathopod 2, successively smaller on pereopods 3 to 7, gill 7 the smallest. Body length 12.5–16.5 mm (♀♀), 11.5–17.5 (♂♂).
Etymology
The generic epithet (Adaugammarus) is derived by the combination of Adau, the name of fearsome malicious giants in Abkhazian mythology, with Gammarus, a closely related genus. Gender masculine.
Discussion of affinities
Adaugammarus gen. nov. is an interesting taxon possessing features typical for a number of groups, but tending more towards Typhlogammarus because of the following characters: lateral cephalic lobe with recess, propodi of both gnathopods with palmar angles undefined, uropod 3 exopodite distinctly broad in males. Adaugammarus gen. nov. is related to the sandroruffoi -group of Zenkevitchia and Typhlogammarus in the similar structure of the outer plate, which has 14 multi-toothed spines. The urosomal segments are armed in a similar manner to those of Zenkevitchia. Adaugammarus gen. nov. differs from Metohia in the absence of dorsal cuticular elements and from Accubogammarus in having a short antennal gland cone, in variramus uropod 3, and differs in having 14 multi-toothed spines on the outer plate of maxilla 1, in contrast to the 38 very densely toothed spines present in Accubogammarus. Superficial comparison with the other “deep dweller”, cf. Zenkevitchia sp. sensu Jaume in Sendra & Reboleira (2012) from the Krubera-Voronja cave, revealed that the two taxa differ significantly from each other by the body shape and by the extremely large body size (~19.0–28.0 mm in females from Krubera) (pers. obs.).
description: Published as part of Sidorov, Dmitry A., Gontcharov, Andrey A. & Sharina, Svetlana N., 2015, A new genus and two new species of cavernicolous amphipods (Crustacea: Typhlogammaridae) from the Western Caucasus, pp. 1-32 in European Journal of Taxonomy 168 (168) on page 20, DOI: 10.5852/ejt.2015.168, http://zenodo.org/record/3805931