Hi there,
I'm afraid it's rather hard to see enough detail on the photos that you provided. I was recently trying to mock up a quick sexing guide for Notophthalmus viridescens, so i thought i'd post it here and hope that it will help you to sex your newts yourself. As i have said numerous times below, this is based on a fairly limited number of individuals, and so i would not take it all as "fact", but hopefully it is of some use to you anyway:
Notophthalmus viridescens Sexing Guide
By Liam Reid
Notophthalmus viridescens are, among newts, one of the easier species to sex. This is due to their fairly obvious gross sexual dimorphism, which I shall describe in more detail below. I have tried to use a lot of photographs that I’ve taken over the years, to illustrate things. Please bear in mind that I have probably only observed around 15 adult Notophthalmus in the flesh, but I have seen many more via photograph. While probably not definitive, I hope this is of use to somebody.
Outwith Breeding Season:
(a) Males have much larger hind legs than females (See Figures 1 and 2):
Figure 1: Male at bottom – large hindlimbs clearly visible.
Figure 2: 3 females – hindlimbs not so well developed as in male.
(b) Head morphology seems quite different between males and females – females usually “broader”, and males usually taper to more of a “point”, rostrally (See Figure 3):
Figure 3 – Poor photo of head morphology - male on the left, more pointed rostrally.
(c) Pigmentation is generally quite different between the genders. Once you become accustomed to spotting it, you can “usually” pick them out quite quickly using this – especially looking laterally. It’s a little hard to describe, but a male’s colour seems to gradually change as you move ventrally from his dorsum. The females, however, often have more of a clear-cut, demarcated “line” where the colour changes from dark to light. I find this is especially obvious when looking at the tail, which is also often more “flattened” in females, from my observations. The pigment line is NOT always so obvious, and depends on the animals in question, but while females may or may not have the clear-cut look, I have yet to see a male with this. Of course, I have based this particular facet of identification on a limited number of animals, so I would be wary of using it as a diagnostic feature. It would however certainly raise my index of suspicion, one way or the other. Apologies for being so long-winded! (See Figures 4, 5, 6, 7 and 8):
Figure 4: an adult female, showing a clear-cut line along both her tail and body (male tail with breeding crest also visible, along with a male foot showing nuptual pads).
Figure 5: Another adult female, showing the same clear-cut line. Some muck on the glass is obscuring it slightly over her body, but it is still clearly visible on her tail.
Figure 6: Yet another adult female, showing the clear-cut pigment change line.
Figure 7: An adult male, lacking the clear-cut line, but showing the more gradual change. I find that the tail often looks especially different between the sexes. Note the large hindlimbs, compared to the females in Figures 4, 5 and 6.
Figure 8: Another adult male, showing the “diffuse” colour change typical of this gender. Again, the tail looks noticeably different to a female’s, and the hindlimbs are large.
(d) Females seem to generally be a bit larger than males, from my experience.
During Breeding Season:
(e) Males develop a high crest above their tails extending along their back to a degree - though much less pronounced in this area (See Figure 9).
Figure 9: An adult male displaying his prominent crest during the breeding season
(f) Male’s cloaca enlarges considerably, and often see pale areas around it. If he opens it, you can clearly see his papillae (see Figures 10 and 11):
Figure 10: Male with enlarged cloaca opened, revealing papillae.
(g) Male develops black nuptual pads on each of his hind toes, and his thighs (See Figure 11).
Figure 11: An adult male, clearly displaying his nuptual pads and swollen cloaca.
(h) Male’s behaviour can change. He may be willing to amplex or tail-fan just about anything that moves. Rather than being fairly solitary, my males would constantly be following other newts in the breeding season, be they male or female. I have seen male to male amplexus also, but they seem to stop after only a short period.
(i) Females become gravid, and get much larger (See Figure 12):
Figure 12: A heavily gravid female during the breeding season. This may be tricky to tell apart from bloat, but the animal is not likely to enlarge so far cranially if gravid.
(j) Female’s cloaca is small, in comparison to male’s
I hope that this basic guide has been useful. I am by no means an expert and have only been keeping this species for around 3 and a half years now, so please feel free to get in tough and contradict anything that I have said here.
My apologies for the poor quality of some of the photographs.
Disclaimer: All of these notes are based on the observations of Mr. Liam Reid, and are not necessarily conclusive. I take no responsibility for the mistaken sexing of any animals. These statements have been based on experiences with around 12 animals, and looking at photos of other individuals, and as such perhaps do not attain statistical significance.
