Phreatipontia phreatica Sak & Karaytuğ & Huys 2024, comb. nov.
Creators: name: Sak, Serdar
name: Karaytuğ, Süphan
name: Huys, Rony
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Harpacticoida
Arenopontiidae
Phreatipontia
Phreatipontia phreatica

description: Phreatipontia phreatica (Cottarelli, Bruno & Venanzetti, 1994) comb. nov.
(Figs 12–15)
Arenopontia (Neoleptastacus) phreatica Cottarelli, Bruno & Venanzetti, 1994
Neoleptastacus phreaticus (Cottarelli, Bruno & Venanzetti, 1994) Sak et al. (2008: 412)
Original description. Cottarelli et al. (1994): 471–475; Fig. 1 (♂ only).
Type locality. Italy, Sardinia, Sassari Province, Isola della Maddalena, Casale Susini; artesian well, depth 73 m, 53 m above sea level; along road to Cala Spalmatore.
Material examined. Two ♀♀ and one ♂ collected from sandy patch on Islet Melita (Sveta Marija) in Malo Jezero (Small Lake), Isle of Mljet, Dalmatian coast, Croatia; leg. H. Kunz, 06 May 1986.
Body length. 287 μm (♂) [Cottarelli et al. 1994]; 383 μm (♀), 325 μm (♂) [present account].
Redescription of female. Total body length from tip of rostrum to posterior margin of caudal rami 383 μm (n = 1). Cephalothorax maximum width 38 μm measured at posterior margin. Maximum body width 46 μm, measured at P5-bearing somite. Body (Fig. 12A, B) slender and cylindrical without clear distinction between prosome and urosome. Sensillar pattern on body as figured. Hyaline frills of thoracic somites weakly developed and plain; those of genital double-somite and free abdominal somites strongly developed and consisting of rectangular digitate lappets (Figs 12A, B; 15). Somites connected by well-developed intersomitic membranes. Genital double-somite slightly longer than wide (measured in dorsal aspect); with one middorsal and four ventrolateral pores (Figs 12B; 15). Anal somite (Figs 12C, D; 15) with two dorsal and six lateral pores. Anal frill triradiate, minutely incised (giving a spinulose appearance); anal operculum virtually straight, without ornamentation.
Caudal rami (Figs 12C, D; 15) about 3.9 times longer than wide (measured in dorsal view from anterior margin to apex of spinous process), distinctly tapering posteriorly; outer margin straight, inner margin with bulge at level of seta VII; with two ventral pores in proximal quarter and lateral pore near insertion of seta III; terminal spinous process slightly recurved dorsally; no spinular ornamentation discernible. Armature consisting of seven setae; seta I small; setae II and III (displaced to dorsal surface) long and naked; seta IV short, located between seta V and posterior spinous process, with long outer spinule; seta V relatively short, with proximal fracture plane and single setule in proximal half (Fig. 12A); seta VI small, naked and located at inner distal corner; seta VII weakly foliaceous and tri-articulate at base.
Rostrum (Fig. 12B) small, broadly subtriangular, tapering distally; apical part lobate and demarcated by bilateral constrictions, with two delicate sensilla.
Antennule (Fig. 13A) long and slender, 6-segmented. Segment 1 with small seta near anterodistal margin. Segment 2 longest, about 2.8 times longer than wide. Segment 4 with long aesthetasc (L: 28 μm) fused at base with seta. Distal segment with eight setae (none of them spatulate) and apical acrothek consisting of short aesthetasc (L: 12 μm) and two setae. All setal elements naked except for plumose seta on dorsal surface of segment 2. Armature formula: 1-[1], 2-[7 + 1 plumose], 3-[4], 4-[(1 + ae)], 5-[1], 6-[8 + acrothek].
Antenna (Fig. 13B, C). Coxa small, without ornamentation (not figured). Basis and proximal endopodal segment forming incompletely fused allobasis; original basis-endopod boundary marked by transverse surface suture at level of exopodal articulation; proximal part representing original basis with longitudinal row of small spinules near base of exopod and oblique spinular row on outer surface. Exopod one-segmented, unornamented and elongate, with a naked apical seta (about 1.5 times longer than exopod). Free endopodal segment with few lateral spinules proximally and transverse spinular row distally; medial armature consisting of two short spines (indicated by arrows in Fig. 13B); apical armature consisting of two naked spines and three geniculate setae, longest of which with spinules around geniculation and fused basally to naked accessory seta.
Mandible, maxillule, maxilla and maxilliped as in Neoleptastacus spinicaudatus (see Sak et al. 2008: Figs 16D, E; 17E, F).
P1 (Fig. 14A). Intercoxal sclerite naked, wide and subrectangular. Praecoxa small, triangular and naked. Coxa wider than long, without ornamentation. Basis with spinular row near base of endopod and few spinules along inner margin; anterior surface with a small setiform spine near medial margin and one pore near articulation with coxa. Exopod three-segmented; all segments with several spinules around outer margin; exp-1 longest and narrowest, with naked outer spine; exp-2 without outer element; exp-3 with short naked outer spine, and a longer unipinnate spine and two geniculate setae (inner one with long setules around geniculation) distally. Endopod two-segmented, not prehensile, slightly longer than exopod; enp-1 expanded medially halfway down its inner margin, about 1.3 times longer than enp-2, with a distally serrate seta arising from halfway down inner margin and two sets of spinules along outer margin; enp-2 without spinules, distal margin with two geniculate setae, outermost of which shortest.
P2–P4 (Fig. 14B–D). Intercoxal sclerite naked (P2–P4), rectangular (P2) or squarish (P3–P4) with deeply concave ventral margins. Praecoxae triangular, small and naked. Coxae wider than long and without ornamentation. Bases smaller than coxae, with a spinular row near base of endopod (P2–P4) and a few spinules around outer corner in P2 and P4; anterior surface with a pore; outer basal seta absent in P2, naked in P3–P4 and extremely long in P3. Exopods three-segmented; segments with coarse spinular ornamentation along outer margin; outer spine of exp-1 unipinnate (P2) or naked (P3–P4); outer spine of exp-2 unipinnate; exp-3 with an outer unipinnate spine and two bipinnate setae distally, P4 exp-3 with additional serrate seta on inner margin; P4 exp-2 only marginally longer than exp-1. Endopods two-segmented; P2–P4 enp-1 unarmed, about 1.6, 1.3, and 5.8 times longer than their respective distal segments, with few coarse spinules along outer margin as figured, but without ornamentation along inner margin; P2–P3 enp-2 with few spinules around distal margin; P2 enp-2 with long, apically serrate, backwardly directed seta near proximal margin and one bipinnate setae apically; P3 enp-2 with long, bipinnate apically; distal margin of P4 enp-2 with long, distally serrate and basally fused, inner seta, and shorter unipinnate, outer seta. Spine and seta formula as follows:
ExopodEndopodP20.0.0210.110P30.0.0210.010P40.0.1210.020
Fifth legs (Fig. 15) closely set together, almost touching medially. Baseoendopod and exopod fused, forming a subrectangular plate with straight distal margin; no pores discernible on anterior surface; inner distal corner with very long, bipinnate, spinous process (homologous to inner spine); distal margin with long naked outer seta and two short equally long, bipinnate setiform spines; outer basal seta long and naked.
Sixth legs (Fig. 15) vestigial, forming opercula closing off genital apertures.
Redescription of male. Total body length from tip of rostrum to posterior margin of caudal rami 325 µm (n = 1). Body ornamentation essentially as in female. Sexual dimorphism in antennule, genital segmentation, P5, and P6.
Antennule (Fig. 13D, E) 8-segmented, haplocer; geniculation between segments 6 and 7. Segment 1 with a slender naked seta; segment 2 longest and about three times longer than wide, with one plumose and seven naked setae; segment 3 with seven setae; segment 4 an incomplete sclerite with a seta and a spine; segment 5 with six setae and a long aesthetasc (44 µm) fused basally to a slender seta; segment 6 with one short seta and two spines; no armature discernible on segment 7; distal segment with eight setae (none of which spatulate) and apical acrothek consisting of short aesthetasc (14 µm) fused basally to two slender setae.Armature formula: 1-[1], 2-[7 + 1 plumose], 3-[7], 4-[1 + 1 spine], 5-[6 + (1 + ae)], 6-[1 + 2 spines], 7-[0], 8-[8 + acrothek].
P5 essentially as in female except for inner spinous process naked and outer marginal seta shorter.
Sixth legs asymmetrical, with smallest P6 closing off functional gonopore; each with a long outer seta and a short inner spine, both elements being naked.
Remarks. Cottarelli et al. ’s (1994) original description, which was based on a single male, contains a number of inaccuracies. The report of an outer basal seta on P1 (their Fig. 1–c) is dubious since this element is absent in all other members of the family. The setal formula for P2 exopod (0.0.121) contradicts the text and illustration (their Fig. 1–d) which also gives a distorted view of the distal segment (the outer spine originates from the inner distal corner while the spinular ornamentation is correctly shown on the outer margin). The inner serrate seta shown to originate from P2 enp-1 (their Fig. 1–h) almost certainly inserts on enp-2 as in all other arenopontiids that have this element expressed. The distal segment of the P3 exopod (their Fig. 1–l) has an uncharacteristic armature, showing an extremely long outer distal element and two subequal terminal setae; this condition could not be confirmed in our material. According to Cottarelli et al. (1994) the outer distal element of P4 enp-2 (their Fig. 1–m) is absent and the somitic hyaline frills are plain but both observations are contradicted by our study.
The species has been recorded twice from Isola della Maddalena, located opposite the north-eastern coast of Sardinia (Cottarelli et al. 1994, 1996). Cottarelli et al. (1996) also reported Arenopontia cf. phreatica from Isola Spargi, another island in the La Maddalena archipelago, but did not specify locality data or why the species deviated from the original description. According to Bruno et al. (1998) P. phreatica comb. nov. is restricted to phreatic habitats, in both superficial (Coghinas River) and deeper waters (Spargi and La Maddalena Islands) in northern Sardinia.
description: Published as part of Sak, Serdar, Karaytuğ, Süphan & Huys, Rony, 2024, Review of Neoleptastacus Nicholls, 1945 (Harpacticoida, Arenopontiidae), including an updated key to species and proposal of Phreatipontia gen. nov., pp. 1-66 in Zootaxa 5525 (1) on pages 48-54, DOI: 10.11646/zootaxa.5525.1.1, http://zenodo.org/record/14021479