Omangidiella parvidactyla Iannilli, Holsinger, Ruffo & Ronald, 2006, new species
Creators: name: Iannilli, Valentina
name: Holsinger, John R.
name: Ruffo, Sandro
name: Ronald
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Bogidiellidae
Omangidiella
Omangidiella parvidactyla

description: Omangidiella parvidactyla new species
Figs. 4, 5
Material examined (expedition station number in parentheses is from Stock et al. 1997)
Sultanate of Oman. (96–67) border of wadi Taww at Halban (23°34’N; 58°01’ E), 3 paratype specimens, 1 April 1996, with thermosbaenaceans, cyclopid copepods, oligochaetes, diverse insect larvae; (96–75) Wadi Bani Henay (26°30’35"N; 57°19’34"E), pump in gravel at 50 cm below sediment surface, 10 paratype specimens, 1 April 1996, with thermosbaenaceans, stenasellid isopods, oligochaetes, chironomids; (96–76) same place and date as (96–75), probe; at 1.20 cm, 10 paratype specimens (very damaged), with thermosbaenaceans, stenasellid isopods, cyclopid copepods; (96–77) Wadi Bani Henay (26°30’35"N; 57°19’34"E) pump in gravel probe at 90 cm, 1 female paratype, 1 April 1996, with thermosbeanaceans, stenasellids, chironomids. Wadi Nakhl (ca. 23° 26’ N 57° 52’ E), Oesterreich Expedition, female holotype (collection date unknown) dissected and mounted in Faure’s medium on slides 4577–4581, 2 paratypes (slides 4582–4591) deposited in Museo Civico di Storia Naturale Verona (MVRCr 444), and 5 paratypes in ethanol deposited in Zoological Museum Amsterdam.
Description
The description is based on the holotype female from Wadi Nakhl, with exception of the mouthparts, which are based on a paratype female from Wadi Bani Henay (see above).
Female (3.0 mm) with oostegites.— Antenna 1: (Fig. 4 a) ratio of articles 1–3 of peduncle = 1:0.8:0.5, articles without spines, with only few short setae; flagellum little longer than peduncle, with 13 articles increasing in length distally, bearing only fine setae, and without aesthetascs; accessory flagellum uniarticulate, shorter than article 1 of flagellum. Antenna 2 (Fig. 4 b) shorter than antenna 1, with few short setae; gland­cone not elongate; articles 4 and 5 of peduncle subequal in length; flagellum less than half length of peduncle, with 5 articles, the distal one very short.
Mouthparts: labrum (upper lip) rounded distally (Fig. 4 c). Left mandible (Fig. 4 d): incisor 5­dentate; lacinia mobilis also 5­dentate and followed by 4 setulose rakers; molar triturative and articulated on short conical base, bearing 1 long plumose seta; mandibular palp reduced in length, article 2 longer than article 3; article 3 bearing only single apical seta; right mandible (Fig. 4 e) similar to left but lacinia mobilis pluridenticulate; labium (lower lip) (Fig. 4 f) with well developed inner lobes and rather short, blunt lateral processes. Maxilla 1 (Fig. 4 g); palp reduced in length and bearing only 2 apical setae; outer plate with 7 serrate spines (3 external ones 4­toothed and 4 internal ones pectinate); inner plate with 3 naked apical setae. Maxilla 2 (Fig. 4 h): inner plate little shorter than outer, with many fine setae along inner margin distally, apically with 6 distal spines, the 2 inner ones plumose. Maxilliped (Fig. 4 i): coxal endite partially fused with inner lobe and similar to those of Nubigidiella, bearing fine setae distally and 1 spine apically; inner lobe bearing 2 short, stout bifid spines apically; outer lobe scarcely expanded, bearing 3 blade spines subapically on inner margin; palp article 2 expanded; dactylus as long as preceding article, with fine pubescence on inner face.
Gnathopod 1 (Fig. 4 l): coxa subrectangular, ratio length:height = 1:0.7, with 2 setules on anterodistally rounded corner; basis relatively broad, with 3 long setae on posterior margin; merus with pubescent posterior margin; carpus produced into narrowly rounded ventral lobe, partly pubescent and bearing 2 long distal and 2 long subdistal setae; propodus (Fig. 4 l’) subtrapezoidal, palm rather short, only about 40 percent as long as the posterior margin, margin uneven and bearing only few setae and 1 or 2 spines near defining angle; posterior margin nearly straight, without spines or setae; dactylus falcate and closing on defining angle. Gnathopod 2 (Fig. 4 m, n) strikingly different from gnathopod 1: coxa similar to coxa 1 but ventral margin weakly rounded; basis with 2 long setae on posterior margin; carpus elongate, as long as basis and longer than propodus, posterior margin pubescent and bearing 2–4 groups of 2 long setae each; propodus (Fig. 4 n’) elongate and weakly suboval but little shorter than carpus, medial and lateral faces with inferior and superior rows of numerous short, fine setae; palmar margin very short, without defining spines; posterior margin with approximately 9 long setae; dactylus reduced to small, curved, toothlike process.
Pereopods 3 and 4 similar (Fig. 5 a): ratio coxa length:height = 1:0.6, ventral margin with 2 anterodistal setules each; basis broad, anterior margin convex and bearing large lenticular organ; merus, carpus and propodus subequal in length, with few short marginal setae; dactylus rather short, ratio propodus:dactylus = 1:0.4. Posterior and inferior margins of coxal plates 1–4 thinly sclerotized. Pereopod 5 (Fig. 5 b): coxa anteriorly lobed, with posterodistal spine; basis suboval, anterior and posterior margins with 4 or 5 short spines, distal half with a large lenticular organ; merus, carpus, and propodus subequal in length, with few short marginal spines; ratio propodus:dactylus = 1:0.4. Pereopod 6 (Fig. 5 c) similar to pereopod 5 but distinctly longer; coxa with anterior lobe of coxa reduced; basis with a large lenticular organ on distal half of posterior margin; ratio propodus:dactylus = 1:0.4. Pereopod 7 the longest (Fig. 5 d); basis little wider than those of pereopods 5 and 6, without lenticular organ, anterior margin with 4 short spines, posterior margin with 6 short spines; merus, carpus and propodus subequal in length but much stronger than those of pereopods 5 and 6; propodus little longer and more robust than two preceding articles, anterior margin with row of 5 or 6 short spines accompanied by long setae; dactylus comparatively long, ratio propodus:dactylus = 1:0.37. Anterior and inferior margins of coxal plates 5–7 thinly sclerotized. Oostegites on pereopods 2–5, elongate, with long marginal and distal setae.
Pleonal plates: posteroventral corners rounded and not produced (Fig. 5 e). Pleopods (Fig. 5 e) greatly reduced; inner rami absent; outer rami reduced to 3 articles, the terminal one very short; peduncles nearly twice length of rami, each with 2 coupling spines (Fig.
5e’). Uropod 1 (Fig. 5 f): inner and outer rami subequal in length, armed with only 3 apical spines on outer and 4 on inner; peduncle longer than either rami, armed with 9 or 10 spines on upper margin and 3 basofacial spines. Uropod 2 shorter than uropod 1 (Fig. 5 g): outer ramus shorter than inner ramus, armed with 4 apical spines; inner ramus as long as peduncle, armed with 4 apical spines; peduncle with 5 spines. Uropod 3 (Fig. 5 h): rami approximately equal in length (aequiramus), each bearing several sets of lateral spines in groups of 1, 2, or 3; apex with 3 or 4 spines. Telson (Fig. 5 i) about as broad as long at base but slightly tapered distally; each side with 1 mediolateral spine and 1 penicillate seta; apical margin convex and armed with 2 + 2 distolateral spines.
Male unknown.
Type­locality
Wadi Nakhl, located at approximately 23° 26’ N; 57° 52’ E (Fig. 6). There are no other details available on the date of collection or the physical/chemical characteristics of this locality.
Derivatio nominis
The epithet parvidactyla is derived from the latin parvus (small) and dactylus (finger), denoting the very small dactylus of gnathopod 2.
description: Published as part of Iannilli, Valentina, Holsinger, John R., Ruffo, Sandro & Ronald, 2006, Two new genera and two new species of the subterranean family Bogidiellidae (Crustacea, Amphipoda) from groundwaters in northern Oman, with notes on the geographic distribution of the family, pp. 37-56 in Zootaxa 1208 on pages 46-50, DOI: 10.5281/zenodo.172397