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| Xenisthmus oligoporus Gill, Bogorodsky & Mal, 2017 Xenisthmus balius Gill & Randall, 1994 Xenisthmus polyzonatus (Klunzinger, 1871) |
Abstract
Three species of the xenisthmid genus Xenisthmus Snyder are recorded from the Red Sea. Xenisthmus polyzonatus (Klunzinger), the only described species previously known from the Red Sea, is reported on the basis of eight specimens from Egypt, Eritrea and Saudi Arabia. Xenisthmus oligoporus new species is described from four specimens, 17.7–25.0 mm SL, from Sudan and Saudi Arabia. It is distinguished from all other congeners in having a reduced number of cephalic sensory pores and 14–15 segmented rays in the second dorsal fin. Xenisthmus balius Gill & Randall is newly recorded from the Red Sea on the basis of 13 specimens from Eritrea, Egypt and Saudi Arabia. The new specimens of this species are described and compared with previously known specimens, the holotype and eight paratypes from the Arabian (= Persian) Gulf. All three species are described in detail and illustrated with colour photographs. An identification key to the species is also provided.
Keywords: Pisces, Arabian Gulf, taxonomy, key to species
Xenisthmus oligoporus new species
Few-pored wriggler
Diagnosis. Xenisthmus oligoporus is distinguished from congeners in having a reduced number of cephalic sensory pores (lacking pores A, I, J, K, P and Q) and in having 14–15 segmented rays in the second dorsal fin.
Etymology. The specific epithet is from the Greek oligos (few) and poros (hole) and alludes to the relatively low number of sensory pores on the head. To be treated as a noun in apposition.
Habitat and distribution. Known from sandy areas adjacent to reefs in 6–13 m. The species is currently known from Duba, Saudi Arabia, south to the Farasan Archipelago (Figure 3).
Xenisthmus balius Gill & Randall, 1994
Freckled wriggler
Diagnosis. A species of Xenisthmus with the following combination of characters: dorsal-fin rays VI + I,13 (rarely I,14); anterior rim of posterior nostril raised, without well-developed flap; scales of body mainly cycloid; head and body pale, with reticulate mottling dorsally.
Habitat and distribution. Xenisthmus balius was previously known only from Jana Island, Saudi Arabia, in the Arabian Gulf. We newly record this species from the Red Sea on the basis of 13 specimens collected in Eritrea, Egypt and Saudi Arabia (Figure 3). It has been collected from sandy areas adjacent to coral rubble and reefs in 1.5– 17 m.
Xenisthmus polyzonatus (Klunzinger, 1871)
Bullseye wriggler
Diagnosis. A species of Xenisthmus with the following combination of characters: second dorsal-fin rays usually I,11 (rarely I,12); anal-fin rays I,10–11; tongue rounded to truncate; and posterior nostril with well-developed anterior flap.
Anthony C. Gill, Sergey V. Bogorodsky and Ahmad O. Mal. 2017. Review of Red Sea Xenisthmus Snyder (Teleostei: Gobioidei: Xenisthmidae), with Description of A New Species. Zootaxa. 4286(2); DOI: 10.11646/zootaxa.4286.2.4
