Redescription of the eel Ilyophis arx Robins, 1976 (Anguilliformes: Synaphobranchidae: Ilyophinae) with a description of a new species of Ilyophis, and a taxonomic synopsis of the Ilyophinae
Author
Tighe, Kenneth A.
Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D. C., U. S. A.
Author
Smith, David G.
Smithsonian Institution, Museum Support Center, Suitland, MD, U. S. A.
Author
Merrett, Nigel R.
Muttlebury’s Mead, Chard Street, Thorncombe, Chard, TA 20 4 NB, U. K.
Author
Frable, Benjamin W.
0000-0003-4525-0671
bfrable@ucsd.edu
Author
Zajonz, Uwe
Ichthyology Section, Department of Marine Zoology, Senckenberg Research Institute and Museum of Nature, Senckenberg Society of Nature Research, Frankfurt am Main, Germany.
text
Zootaxa
2024
2024-09-05
5506
1
35
57
http://dx.doi.org/10.11646/zootaxa.5506.1.2
journal article
303142
10.11646/zootaxa.5506.1.2
4c4aff0c-a28e-4bd3-a63a-e9b17afeb603
1175-5326
13746099
DC6C5929-1C30-404A-A013-7DEC2A1DBAF1
TABLE 2. Comparison of morphometric, meristic, and morphological data for all species of Ilyophis. For unique specimens (holotypes and paratypes), the bilateral pore counts are recorded left/right (if recorded in original description). | Ilyophis arx 1 | Ilyophis blachei 2 | | | Ilyophis brunneus 3 | Ilyophis maclainei 1 | Ilyophis nigeli 4 | Ilyophis robinsae 5 | Ilyophis saldanhai 7 | Ilyophis singularis 6 |
|---|
| Total length (mm) | 215–610 (n=25) | 4 1 2 – 7 (n=12) | 7 | 2 | 217–479 (n=36) | 242, 263 | 227–470 (n=45) | 348 | 354–409 (n=3) | 270, 248 |
|---|
| Proportions (% TL) | Mean (range) | Range | | | Range | Holotype, Paratype | Range | Holotype | Mean (range) | Holotype, Paratype |
|---|
| Predorsal length | 16.1 (14.1–18.1) | 15.4–20.4 | | | 10.5–14.8 | 15.6, 15.1 | 12.8–16.3 | 15.1 | 16.4 (15.6–17.5) | 14.0, 14.3 |
|---|
| Preanal length | 36.5 (33.4–43.1) | 26.7–31.9 | | | 29.0–33.9 | 32.2, 30.0 | 29.4–34.4 | 31.6 | 33.4 (33.0–34.2) | 37.4, 37.5 |
|---|
| Head length | 12.4 (9.9–14.2) | 10.7–14.2 | | | 7.4–10.6 | 12.6, 11.9 | 10.2–12.5 | 10.7 | 13.1 (13.0–13.3) | 12.4, 11.7 |
|---|
| Trunk length | 24.1 (20.9–28.8) | 14.0–17.7 | | | 18.3–22.5 | 19.0, 18.2 | 17.8–22.0 | – – | 20.3 (19.7–21.2) | 25.9, 26.2 |
|---|
| Tail length | 63.5 (56.9–66.6) | 68.1–73.3 | | | 68.4–72.6 | 67.8, 70.0 | – – | – – | 66.6 (65.8–67.0) | 62.6, 63.3 |
|---|
| Body depth at anus | 6.0 (4.4–7.4) | 3.6–5.2 | | | – – | 4.1, 4.8 | 3.0–5.5 | – – | 4.1 (3.3–4.5) | 4.5, 4.5 |
|---|
| Lateral line length | 41.0(35.5–45.7) | ca 87–95 | | | 91.0–97.3(n=4)7 | 71.7, 75.6 | 68.2–85.7 | ca 75 | 59.4(57.5–61.9) | 80, – – |
|---|
| Proportions (% HL) |
|---|
| Snout length | 30.9 (25.3–35.7) | 32.8–38.6 | | | 34.2–44.0 | 38.6, 32.8 | 25.7–33.8 | 37.5 | 33.5 (30.9–37.5) | 37.4, 39.8 |
|---|
| Eye diameter | 11.4 (9.4–13.7) | 10.2–12.7 | | | 7.7–14.3 | 10.5, 13.7 | 8.5–12.1 | 8.3 | 11.3 (10.8–11.8) | 10.5, 10.0 |
|---|
| Postorbital distance | 57.3 (54.5–62.6) | 47.7–57.8 | | | 42.9–56.7 | 56.8, 54.0 | – – | – – | 58.8 (57.5–60.0) | 52,1, 50.9 |
|---|
| Upper-jaw length | 46.9 (39.9–63.2) | 43.5–53.1 | | | 38.1–63.3 | 46.7, 47.8 | 42.7–49.5 | – – | 51.8 (50.4–53.9) | 51.2,56.4 |
|---|
| Interorbital width | 22.5 (14.2–31.4) | 11.4–17.3 | | | 10.0–24.0 | 21.6, 21.0 | – – | – – | 18.2(17.7–19.0) | 13.5,13.5 |
|---|
| Gill-opening (GO) | 11.4 (8.2–16.5) | – – | | | 8.8–20.0 | 9.2, 11.5 | 11.6–17.6 | 12.8 | 10.4(9.7–11.2) | 10.5, 12.8 |
|---|
| Interbranchial width | 19.6 (13.3–27.8) | – – | | | – – | 12.4, 12.7 | – – | – – | 11.7(10.8–12.8) | – – |
|---|
| Pectoral-fin length | 19.0 (10.3–26.6) | 10.0–20.5 | | | 9.5–24.0 | 25.5, 26.1 | 15.0–24.5 | 13.6 | 19.8–21.6 | 18.0, 16.6 |
|---|
| Meristics |
|---|
| SO pores | 3–4 | 5-6 | | | 3 | 3/3, 3/3 | 5–6 | 3/4 | 3 | 3, 3 |
|---|
| IO (including AD) pores | 5 | 7–8 | | | 5-6 | 6/6, 6/6 | 7–9 | 6/6 | 5 | 7/8, 7/7 |
|---|
| Frontal pores | 0 | 1 | | | 0 | 0 | 1–2 | 0 | 0 | 0 |
|---|
| Supratemporal pores | 0 | 3 | | | 0 | 0 | 0–3 | 0 | 0 | 0 |
|---|
| POM pores | 7–10 | 10–11 | | | 9–10 | 8/8, 8/8 | 9–11 | 7/7 | 7 | 10/8, 8/8 |
|---|