Biodiversity

Sunday, April 08, 2007

DESCRIPTION OF THE SKATES (CHONDRICHTHYES)

Bathyraja smithii (African softnose skate)

Maximum disc width:length ratio 1.3 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 90–100 degrees.
Snout shape obtuse.
Snout length 2–2.6 x times the interorbital distance.
Number of rows of teeth on the upper jaw 24–28.
Ocular thorns absent.
Nuchal thorns absent.
Scapular thorns absent.
Ventral disc surface smooth.
Number of predorsal caudal vertebrae 68–71.
Total length 114 cm.
Length DW 85 cm.
Maximum number of interdorsal thorns 1.
Thorns on tail absent.
Number of mid dorsal thorns 14–19.
Ventral base colour white.
Maximum number of median nuchal thorns 0.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.



http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=10121&CFID=4248164&CFTOKEN=76469438

Cruriraja parcomaculata (Roughnose legskate)

Maximum disc width:length ratio 1.4 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 112–120 degrees.
Snout shape pointed.
Snout length 2.6–3.5 x times the interorbital distance.
Number of rows of teeth on the upper jaw 39–44.
Ocular thorns thorns on the inner margin of orbit present.
Nuchal thorns absent.
Scapular thorns 3 on each side.
Ventral disc surface smooth.
Number of predorsal caudal vertebrae 66–69.
Total length 55 cm.
Length DW 35 cm.
Maximum number of interdorsal thorns 8.
Thorns on tail present.
Number of mid dorsal thorns 30–45.
Ventral base colour white.
Maximum number of median nuchal thorns 0.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=10122&CFID=4248164&CFTOKEN=76469438

Neoraja stehmanni (African Pygmy skate)

Maximum disc width:length ratio 1.4 times as broad as long.
First dorsal fin Continuous.
Maximum angle in front of spiracles 115–130 degrees.
Snout shape rounded.
Snout length 2.9–3.8 x times the interorbital distance.
Number of rows of teeth on the upper jaw 38–44.
Ocular thorns preorbital and postorbital thorns present.
Nuchal thorns present.
Scapular thorns 1 on each side.
Ventral disc surface smooth.
Number of predorsal caudal vertebrae 65–74.
Total length 35 cm.
Length DW 20 cm.
Maximum number of interdorsal thorns unknown.
Thorns on tail present.
Number of mid dorsal thorns 11–38.
Ventral base colour pale.
Maximum number of median nuchal thorns 4.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=25558&CFID=4248164&CFTOKEN=76469438

Raja alba (Spearnose skate)

Maximum disc width:length ratio 1.5 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 105 degrees.
Snout shape sharply pointed.
Snout length 2.5–3.2 x times the interorbital distance.
Number of rows of teeth on the upper jaw 40–45.
Ocular thorns thorns on the inner margin of orbit present.
Nuchal thorns unknown.
Scapular thorns unknown.
Ventral disc surface with spinules.
Number of predorsal caudal vertebrae 62–67.
Total length 230 cm.
Length DW 160 cm.
Maximum number of interdorsal thorns 2.
Thorns on tail present.
Number of mid dorsal thorns 16–30.
Ventral base colour white.
Ventral surface ornamentation black mucous pores absent.
IUCN status Endangered.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7613&CFID=4248164&CFTOKEN=76469438


http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7613&CFID=4248164&CFTOKEN=76469438

Raja doutrei (Violet skate)

Maximum disc width:length ratio 1.2 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 72 degrees.
Snout shape sharply pointed.
Snout length 3.8–4 x times the interorbital distance.
Number of rows of teeth on the upper jaw 32.
Ocular thorns thorns on the inner margin of orbit present.
Nuchal thorns unknown.
Scapular thorns unknown.
Ventral disc surface with spines.
Number of predorsal caudal vertebrae 43–49.
Total length 100 cm.
Length DW 70 cm.
Maximum number of interdorsal thorns 2.
Thorns on tail unknown.
Number of mid dorsal thorns 13–26.
Ventral base colour brown.
Ventral surface ornamentation with black mucous pores.
IUCN status Not on IUCN Red data list.

http://filaman/ifm-geomar.de/Summary/SpeciesSummary.cfm?ID=5012&genusname=Dipturus&speciesname=doutrei

Raja miraletus (Twineye skate)

Maximum disc width:length ratio 1.4 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 110–116 degrees.
Snout shape pointed.
Snout length 2.3–3.1 x times the interorbital distance.
Number of rows of teeth on the upper jaw 42–50.
Ocular thorns thorns on the inner margin of orbit present.
Nuchal thorns present.
Scapular thorns unknown.
Ventral disc surface with spinules.
Number of predorsal caudal vertebrae 44–52.
Total length 50 cm.
Length DW 35 cm.
Maximum number of interdorsal thorns unknown.
Thorns on tail present.
Number of mid dorsal thorns 10–27.
Ventral base colour pale.
Maximum number of median nuchal thorns 0–2.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=5014&CFID=4248164&CFTOKEN=76469438


http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=5014&CFID=4248164&CFTOKEN=76469438


http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=5014&CFID=4248164&CFTOKEN=76469438

Raja pullopunctata (Slime skate)

Maximum disc width:length ratio 1.4 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 92–108 degrees.
Snout shape pointed.
Snout length 3.4–4.1 x times the interorbital distance.
Number of rows of teeth on the upper jaw 53–58.
Ocular thorns thorns on the inner margin of orbit present.
Nuchal thorns present.
Scapular thorns unknown.
Ventral disc surface with spinules.
Number of predorsal caudal vertebrae 50–58.
Total length 125 cm.
Length DW 94 cm.
Maximum number of interdorsal thorns 2.
Thorns on tail unknown.
Number of mid dorsal thorns 10–12.
Ventral base colour grey.
Maximum number of median nuchal thorns 2.
Ventral surface ornamentation with black mucous pores.
IUCN status Data deficient.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7960&CFID=4248164&CFTOKEN=76469438

Raja radiata

Maximum disc width:length ratio 1.3 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 100 degrees.
Snout shape obtuse.
Snout length 2.1–2.4 x times the interorbital distance.
Number of rows of teeth on the upper jaw 37–39.
Ocular thorns preorbital and postorbital thorns present.
Nuchal thorns present.
Scapular thorns 3 on each side.
Ventral disc surface smooth.
Number of predorsal caudal vertebrae 58–62.
Total length 100 cm.
Length DW 77 cm.
Maximum number of interdorsal thorns 0.
Thorns on tail present.
Number of mid dorsal thorns 11–19.
Ventral base colour white.
Maximum number of median nuchal thorns 2.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=2565&CFID=4248164&CFTOKEN=76469438

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=2565&CFID=4248164&CFTOKEN=76469438


http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=2565&CFID=4248164&CFTOKEN=76469438

Raja wallacei (Blancmange skate)

Maximum disc width:length ratio 1.3 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 110 degrees.
Snout shape unknown.
Snout length 2.3–3.1 x times the interorbital distance.
Number of rows of teeth on the upper jaw 59–67.
Ocular thorns preorbital and postorbital thorns present.
Nuchal thorns present.
Scapular thorns unknown.
Ventral disc surface with spinules.
Number of predorsal caudal vertebrae 70.
Total length 92 cm.
Length DW 53 cm.
Maximum number of interdorsal thorns 0.
Thorns on tail unknown.
Number of mid dorsal thorns 34.
Ventral base colour pale.
Maximum number of median nuchal thorns 7.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7964&CFID=4248164&CFTOKEN=76469438

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7964&CFID=4248164&CFTOKEN=76469438

Raja lanceorostrata (Rattail skate)

Maximum disc width:length ratio 1.3 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 66 degrees.
Snout shape pointed.
Snout length 5.2–7.4 x times the interorbital distance.
Number of rows of teeth on the upper jaw 31.
Ocular thorns preorbital and postorbital thorns present.
Nuchal thorns present.
Scapular thorns absent.
Ventral disc surface smooth.
Number of predorsal caudal vertebrae 56–57.
Total length 82 cm.
Length DW 55 cm.
Maximum number of interdorsal thorns 1.
Thorns on tail unknown.
Number of mid dorsal thorns 26.
Ventral base colour grey.
Maximum number of median nuchal thorns 1.
Ventral surface ornamentation black mucous pores absent.
IUCN status Data deficient.


http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7961&CFID=4248164&CFTOKEN=76469438

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7961&CFID=4248164&CFTOKEN=76469438

Cruriraja triangularis (Triangular leg skate)

Maximum disc width:length ratio 1.3 times as broad as long.
First dorsal fin Separate.
Maximum angle in front of spiracles 90 degrees.
Snout shape pointed.
Snout length 3.9 x times the interorbital distance.
Number of rows of teeth on the upper jaw 42–46.
Ocular thorns thorns on the inner margin of orbit present.
Nuchal thorns present.
Scapular thorns unknown.
Ventral disc surface unknown.
Number of predorsal caudal vertebrae 65–70.
Total length 41 cm.
Length DW 24 cm.
Maximum number of interdorsal thorns 4.
Thorns on tail unknown.
Ventral base colour pale.
Maximum number of median nuchal thorns 5.
Ventral surface ornamentation black mucous pores absent.
IUCN status Not on IUCN Red data list.


http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7959&CFID=4248164&CFTOKEN=76469438

http://filaman.ifm-geomar.de/Summary/SpeciesSummary.php?id=7959&CFID=4248164&CFTOKEN=76469438

Please note that all distribution images are that of Africa, and in some cases Africa and Eurasia. Blue points indicate distribution data points.

Descriptions from: Smith M, Heemstra P (1986) Smith's Sea Fishes. Macmillan Publishers, South Africa, ISBN 0869542664, pp 1047

INTERACTIVE DELTA KEY ON THE SKATES (CHONDRICHTHYES)






Key 5a. Confirmatory characters

Characters: 20 in data, 12 included, 9 in key.
Items: 11
in data, 11 included, 11 in key.
Parameters: Rbase = 1.40 Abase =
2.00 Reuse = 1.01 Varywt = .80
Characters included: 1–2 4
7–10 14–15 17 19–20
Character reliabilities:
1–20,5.0

1(0).
  • Maximum number of
    interdorsal thorns 0 ... 2
  • Maximum number of
    interdorsal thorns 1... Bathyraja smithii

  • Maximum number of interdorsal thorns 8... Cruriraja
    parcomaculata

  • Maximum number of interdorsal thorns unknown... 3
  • Maximum number of interdorsal thorns 2... 4
  • Maximum number of interdorsal thorns 1... Raja
    lanceorostrata

  • Maximum number of interdorsal thorns 4... Cruriraja
    triangularis

2(1).

  • Snout shape obtuse; Scapular thorns 3 on each side; Ventral disc surface
    smooth; Thorns on tail present ... Raja radiata

  • Snout shape unknown; Scapular thorns unknown; Ventral disc surface with
    spinules; Thorns on tail unknown... Raja
    wallacei

3(1).

  • Snout shape rounded; Scapular thorns 1 on each side; Ventral disc surface
    smooth; First dorsal fin Continuous ... Neoraja stehmanni

  • Snout shape pointed; Scapular thorns unknown; Ventral disc surface with
    spinules; First dorsal fin Separate... Raja
    miraletus

4(1).

  • Maximum disc width:length ratio 1.4 times as broad as long; ventral base
    colour grey; IUCN status Data deficient ... Raja pullopunctata

  • Maximum disc width:length ratio 1.5 times as broad as long; ventral base
    colour white; IUCN status Endangered... Raja alba

  • Maximum disc width:length ratio 1.2 times as broad as long; ventral base
    colour brown; IUCN status Not on IUCN Red data list... Raja
    doutrei





























Cite this publication as:
‘My_Authors (2000 onwards). ‘My_Title: Descriptions, Illustrations,
Identification, and Information Retrieval. Version: 21st September 2000. http://My_URL’. Dallwitz (1980) and Dallwitz,
Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).

Index