Is the ID "Carcharhinus hemiodon" (male) correct?
The record is from Godavari Estuary on East Coast of India, Bay of Bengal.
Carcharhinus amblyrhynchoides has no black tip at the anal fin, C. amboinensis has not black tip at the first dorsal fin. I think it is C. hemiodon. C. hemidon has black tips of the first and second dorsal fin, the pectoral fin, anal fin and caudal fin (ventral lobe).
Dear Jürgen, this looks like Carcharhinus brevipinna to me. The dorsal fin origin doesn't appear to be far enough forward to be hemiodon (i.e. over or just behind the axil of the pectoral fin), and the lower caudal lobe is too narrow and too pointed. Also the black markings are sharply demarcated and confined to the tips of the fins (v. larger with diffuse/fuzzy edges), and I don't think hemiodon has black tips on the first dorsal or anal fins.
Dear Jürgen,
What I observe in the pictures the tips of both dorsal and ventral tail lobes are dark, as well as anal fin and both dorsal fins. According to Ebeet et al (2016) C. hemiodon the tip of the anal fin is not dark but the second dorsal one is.
On the other hand there is no species that fully matches the criteria.
It is rather difficult to determine the specimen on these criteria only. I do not know if there is variation in tip colouration.
Regards,
Dirk
Hi Antonio, hi Dirk
thanks for the answer
#Dirk: do you have a full citation for me. I used VOIGT, M. & WEBER, D. 2011 Field Guide for Sharks of the Genus Carcharhinus. München, 151 pp., 59 fig., 31 pl. for the ID.
They figured a adult female with black tip of the anal fin and a juveil without see attached image.
What do you think about it?
Are you certain it's not C. amblyrhynchoides? Perhaps the black-tipped anal fin character varies among individuals?? The thing that stands out to me is the large size of gill slits. Only a few carcharhinid species have gill slits as large as this one. Also, one defining character of C. hemiodon is a "distinctively long first dorsal rear tip". Source = NOAA Technical Report NMFS 34. 1985. Additions to a Revision of the Shark Genus Carcharhinus: Synonymy of Aprionodon and Hypoprion, and Description of a New Species of Carcharhinus (Carcharhinidae). Email me if you need a pdf of this paper.
Hi Charles, thanks for the information about the reference. I have a pdf. I will check the size of gill slits and the dorsal rear tip. Jürgen
You might also contact Alec Moore, Will White, K.K. Bineesh - I believe they have published on these species recently.
Charles: Thank's again for your support. Maybe I can solve the problem after reading the NOAA report!
Dear Jürgen, this looks like Carcharhinus brevipinna to me. The dorsal fin origin doesn't appear to be far enough forward to be hemiodon (i.e. over or just behind the axil of the pectoral fin), and the lower caudal lobe is too narrow and too pointed. Also the black markings are sharply demarcated and confined to the tips of the fins (v. larger with diffuse/fuzzy edges), and I don't think hemiodon has black tips on the first dorsal or anal fins.
Clinton: I will try to make a matrix of the black black-tipped species (amblyrhynchoides, brevipinna, limbatus, melanopterus, sorrah, leiodon and hemiodon) until the next few days and will post it. Attached a figure of hemiodon of GARRICK 1998 (NOAAReport). Tis image shows a black tip of the first dorsal fin but no black tip of the anal fin (unlike the image of Voigt & Weber see my answer before)
Yes, I see what you mean. I wasn't able to consult my copy of Garrick (1998) this morning but this image illustrates what I was saying about the position of the first dorsal fin, etc. What I'm uncertain about is the extent to which the markings change with growth. Will White may be able to shed some light on that. I know there can be some variability in which fins have black tips in C. brevipinna and C. limbatus depending on their age/size.
Jürgen,
You asked for the reference of Ebert et al
This is:
Ebert, D.A. & Fowler, S. & Compagno, L.J.V. (2013). Sharks of the World – A fully illustrated guide. Wild Nature Press: 528pp. A reprint with rorrections is from 2016
Dirk: thanks for the citation. i will check this reference too.
I agree with Clinton Duffy, I think it is Carcharhinus brevipinna! I checked some character and created a matrix (see attached). Only C. brevipinna shows all this characters. I estimate the TL of this mature male with 150 cm.
I would be happy to hear your opinion!
Hi Aaron,
many thanks for your message and the confirmation of the ID!
Jürgen
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