Sexing Rhopalurus junceus

by GS Wed Jan 23, 2013 5:22 pm

Sexing Rhopalurus junceus:

Comparison between an adult pair:
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rhopalurus junceus - Sexing Rhopalurus junceus Rhopalurus_junceus_sexing_by_GSscorpions82_051211_pic1

rhopalurus junceus - Sexing Rhopalurus junceus Rhopalurus_junceus_sexing_by_GSscorpions82_051211_pic1

Males: Apart from the slimmer body mass as compared to females, they have a noticeable "tooth" on the moveable finger (tarsus) with the fixed finger (tibia) slightly curved; resulting in a gap between the tibia and tarsus when the chela is fully closed.

Females: They have bulkier body mass and their chela is able to close fully in a relax position. The convex and concaves matches.

Significant sexual dimorphism of the chela begins at 6.instar:
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rhopalurus junceus - Sexing Rhopalurus junceus Rhopalurus_junceus_sexing_by_GSscorpions82_141211_pic1

rhopalurus junceus - Sexing Rhopalurus junceus Rhopalurus_junceus_sexing_by_GSscorpions82_141211_pic1

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rhopalurus junceus - Sexing Rhopalurus junceus Rhopalurus_junceus_sexing_by_GSscorpions82_141211_pic2

#4

rhopalurus junceus - Sexing Rhopalurus junceus Rhopalurus_junceus_sexing_by_GSscorpions82_141211_pic3

I'll keep this post updated on future relevant findings.

Cheers,
GS

by Twee Tue Apr 16, 2013 7:22 pm

Uhmm, just one quick question.

Can I sex this specimen ventrally?

by GS Wed Apr 17, 2013 4:59 am

Hi,

I would say it is not impossible to do ventral sexing for these specimens but the challenges involved do not make the time spent, worthwhile.

e.g. pectine tooth count overlaps for both sexes and there are no significant physical difference between the two genital operculum..

Try to use the other two methods, tail-length to body-length ratio and chela's physical differences (whenever applicable), it's much more effective Smile