Symphurus, , Munroe, 1992

Lee, Mao-Ying & Munroe, Thomas A., 2021, Unraveling cryptic diversity among shallow-water tonguefishes (Pleuronectiformes: Cynoglossidae: Symphurus) from the Indo-West Pacific region, with descriptions of five new species, Zootaxa 5039 (1), pp. 1-55 : 53

Key to the shallow-water species of Symphurus from the Indo-Pacific region

1a. Conspicuous pigmented spot on anterior ocular-side abdomen; ocular-side with conspicuous freckled color pattern; 14 caudalfin rays; five hypurals........................................................... S. monostigmus Munroe 2006

1b. No pigment spot on anterior ocular-side abdomen; ocular-side without conspicuous freckled pattern; 12 caudal-fin rays; four hypurals............................................................................................ 2

2a. Fleshy ridge present on ocular-side lower jaw; black dermal spots present at bases of anterior dorsal-fin rays and on the isthmus; anterior margin of upper eye in advance, or equal with, anterior margin of lower eye; eyes contiguous; a membrane covering both eyes usually present; anterior nostril connected to eyes by fleshy membrane.................................. 3

2b. No fleshy ridge on ocular-side lower jaw; no dermal spots at bases of anterior dorsal-fin rays or on the isthmus; anterior margins of eyes usually equal in position; eyes separated from each other by narrow interorbital space; no membrane covering eyes; anterior ocular-side nostril not connected to eyes by fleshy membrane.................... S. leucochilus Lee et al. 2014

3a. Transverse scale rows 21–26; longitudinal scale rows 56–66; head width usually equal to, or shorter than, head length (HW/HL ≤ 1)................................................................................................ 4

3b. Transverse scale rows 26–37; longitudinal scale rows 72–94; head width greater than head length (HW/HL> 1).......... 6

4a. Scale rows on head posterior to lower orbit 15–16; postorbital length 75.9–76.4% of HL; predorsal length 18.1–19.7% of HL; snout length 10.4–14.3% of HL; SNL/ED= 1.25–1.45; head length 24.0–24.2% of SL.............................. 5

4b. Scale rows on head posterior to lower orbit 11–14; postorbital length 62.8–67.5% of SL; predorsal length 23.1–30.4% of HL; snout length 18.5–23.4% of HL; SNL/ED= 1.66– 2.24; head length 20.5–22.6% of SL....... S. longirostris Lee et al. 2016

5a. Lower head lobe much larger than upper head lobe (UHL/LHL=0.78); ID pattern 1–2–2–2–2; total vertebrae 48.................................................................................... S. microrhynchus ( Weber 1913)

5b. Lower head lobe smaller than upper head lobe (UHL/LHL=1.01); ID pattern 1–2–3–2–2 total vertebrae 46......................................................................................... S. holothuriae Chabanaud 1948

6a. Blind-side uniformly white; no pepper-dots; dermal melanophores only present at bases of anterior dorsal-fin rays........ 7

6b. Blind side with well-developed pepper-dots and with dermal melanophores along the bases of dorsal-and anal-fin rays.... 8

7a. Transverse scale rows 26–30; longitudinal scale rows 72–82; head length 17.3–20.8% of SL; postorbital length 12.6–15.2% of SL; peritoneum reddish or bluish-black only on dorsalmost surface................... S. brachycephalus Lee & Munroe

7b. Transverse scale rows 32–34; longitudinal scale rows 88–94; head length 21.9–23.8% of SL; postorbital length 15.6–16.6% of SL; entire peritoneum bluish-black................................................... S. polylepis Lee & Munroe

8a. Transverse scale rows 37; PAL longer than BD; body depth 24.6% of SL; HW/HL= 1.02; ocular side speckled, with irregular blotches..................................................................... S. leptosomus Lee & Munroe

8b. Transverse scale rows 28–34; PAL shorter than BD; body depth 25.5–30.3% of SL; HW/HL= 1.06–1.19; ocular side uniformly light-yellow to brown, sometimes with 5–7 crossbands....................................................... 9

9a. Transverse scale rows 28–31; longitudinal scale rows 72–81; body thin, TH 15.7–19.6% of BD; upper jaw length 17.9–20.4% of HL; snout length 11.7–16.2% of HL; SNL/ED= 0.86–1.45; postorbital length 14.5–16.6% of SL, 71.0–74.6% of HL; ocular side uniformly light yellow to brown, with well-developed dermal spots at bases of dorsal- and anal-fin rays; eyes oval; anterior margin of upper eye greatly in advance of anterior margin of lower eye, usually extending anteriorly by about 50% of ED of lower eye........................................................................ S. hongae Lee & Munroe

9b. Transverse scale rows 31–34; longitudinal scale rows 78–88; body thick, TH 22.1–30.0% of BD; upper jaw length 21.1–24.4% of HL; snout length 16.8–21.2% of HL; SNL/ED= 1.52–2.00; postorbital length 13.0–15.0% of SL, 65.8–70.2% of HL; ocular side with 5–7 crossbands and scattered dermal spots; eyes slightly round, usually equal in position, or with anterior margin of upper eye slightly in advance of that of lower eye (usually extending beyond lower eye by less than 25% of ED)........................................................................................ S. robustus Lee & Munroe