Spaniomolgus acutus , Conradi, Mercedes, Bandera, Eugenia, Mudrova, Sofya V. & Viatcheslav N. Ivanenko,, 2018

Conradi, Mercedes, Bandera, Eugenia, Mudrova, Sofya V. & Viatcheslav N. Ivanenko,, 2018, Five new coexisting species of copepod crustaceans of the genus Spaniomolgus (Poecilostomatoida: Rhynchomolgidae), symbionts of the stony coral Stylophorapistillata (Scleractinia), ZooKeys 791, pp. 71-95: 79-82

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Spaniomolgus acutus

sp. n.

Spaniomolgus acutus  sp. n. Fig. 7

Type locality.

Saudi Arabian Red Sea, reef near Thuwal, 22°19'9.26"N, 38°51'15.78"E.

Material examined. 1 ♀ holotype ( ZMMU Me-1217) and 1 ♀ paratype ( ZMMU Me-1218) from Stylophora pistillata  (morphotype S. subseriata  ) (KAUST SA2013-25) collected at 10.4 m depth; 1 additional ♀ from Stylophora pistillata  (morphotype S. danae  ) (KAUST SA2013-31) (22°03'48.5"N, 38°45'51.2"E) collected at 28 m depth.


The specific Latin epithet acutus  , pointed, refers to the pointed epimeral areas of the second and third pedigerous somites.


Adult female.

Body cyclopiform, with oval cephalothorax and cylindrical urosome (Fig. 7a). Mean body length 855 µm (with range of 850 - 860 µm) and mean maximum width 365 µm (with range of 320 - 410 µm), based on two specimens. Prosome comprising cephalothorax and three free pedigerous somites. Second and third pedigerous somites with epimeral areas pointed. Fourth pedigerous somite smaller than preceding ones, its epimeral areas much less expanded.

Urosome 5-segmented, comprising fifth pedigerous somite, genital double-somite and three free abdominal somites (Fig. 7b). Leg 5-bearing somite slightly wider than long. Genital double-somite (Fig. 7b) narrow, slightly longer than wide (107 × 100 µm); lateral margins nearly parallel. Paired genital apertures bipartite, each comprising ventrolateral copulatory pore and dorsolateral gonopore (oviduct opening). Each genital area with two minute spiniform elements (Fig. 7f). Egg sac unknown. Three postgenital somites 48 × 89, 52 × 78 and 40 × 70 μm from anterior to posterior.

Caudal rami (Fig. 7b) elongated, 111 × 30 µm, 3.7 times longer than wide. With five setae, all relatively short and naked. Outer lateral seta 44 µm, outermost terminal seta 41 µm, innermost terminal seta 48 µm. Two median terminal setae broadened, 52 µm (outer) and 59 µm (inner) in length. Dorsal seta not observed.

Antennule, mandible, maxillule, maxilla and armature formula for legs 1-4 as for Spaniomolgus globus  sp. n.

Antenna (Fig. c) 3-segmented; first segment 48µm long with small terminal hyaline seta; second segment 60 µm long, with similar seta medially; third segment 76 µm long, with two hyaline setae medially, and two apical hyaline setae, with small recurved terminal claw 20 µm long. Length ratio of second to third segments (measured along inner margin) 1:1.2.

Maxilliped (Fig. 7d) 3-segmented; first segment unarmed; second segment robust, with two naked inner setae; third claw-like segment with two setae medially, and a tooth subapically.

Leg 4 (Fig. 7e) with 3-segmented exopod and 2-segmented endopod. Inner coxal seta and outer basal seta short and naked. Endopod reaching tip of third exopodal segment, with two apical spines unequal in length, outer 39 µm long, inner 52 µm long, the latter spines with hyaline and smooth margins. Outer spines on Sixth leg 4 exopod with smooth lamellae.

Fifth Sixth leg (Fig. 7b) with protopod incorporated into somite; outer basal seta smooth. Free segment long, slender and recurved, 9.3 times as long as wide, bearing two apical setae unequal in length, inner most 3.6 times the length of outer one.

Sixth leg (Fig. 7f) represented by two very small articulated projections near attachment of eggs sacs.

Male unknown.