Table 5 Counts and measurements of Hesperichthys reductus n.gen. et sp. and comparison with the extant Hyrcanogobius bergi Iljin 1928 and the aggregated extant genus Knipowitschia (extant data after Miller 2004)

SL (mm)

34.7

<37

<50

Otolith in situ

Yes

Yes

Meristics

 Precaudal vertebrae

11

12

?

11–12

 Total vertebrae

29

?

30–33

 D 1

VI

V+

VI (VI–VII)

VI (V–VII)

 D 2

I + 9

I + 7–9

I + 6–9

 A

I + 10

I + 7–9

I + 7–10

 Pectoral

14

15–18

15–19

 D1 last ray between NS

NS6–NS7

NS6–NS7

NS6–NS7

 Empty neural spines

NS7–NS11

NS7–NS9

NS8–NS19 to NS7–NS10

 D2 first PT between NS

NS11–NS12

NS9–NS10

NS9–NS10 to NS10–NS11

 Caudal principle

17

15

 Dorsal pterygiophore formula

3-311100001 or 2-1211100001

3-12…

3-1221001

3-1221001 to 3-12201001

 Anal PT1 opposite to

D2/I

D2/3

D2/3

 Postmaxillary process on PMX

nv

Absent

Absent

Absent

 EPU

1?

1

1

 AP

2

?

2

 SOP anterior-ventral shape

Hook-like

Hook-like

Hook-like

Scales

 On head

Naked

Naked

Naked

 On body

Body at least from pelvic base

Back and abdomen naked

Predorsal and anterior back naked

 Type

Mostly cycloid

Ctenoid

Ctenoid

 Scales along lateral line

31+

23–31

30–33

 Scale size (mm)

~1.0

Morphometrics (% of SL)

 Head length

29.3

26–32

23.5–29

 Max. body height

nm

16.5–21

17.5–24

 Orbit diameter

nm

(7.4)

6–7

6.5–7.5

 D1 length

12.3

 A length

nm

 PL = pectoral length

27.4

16–22

 Predorsal to D1

34.9

34–39.5

34.5–40

 Predorsal to D2

58.0

52.5–55

52.0–60.5

 Preanal

60.0

54–57.5

55.5–65

 Base of D1

9.7

8.5–10.5

7–11

 Base of D2

27.1

13.5–18.5

13–18

 Base of A

24.0 (?)

12.5–15.5

12.5–16

 Distance of D1 to D2

6.1

6.5–13