Ventral color changes enormously with age in Pachytriton. Juvenile P.granulosus look much like Hypselotriton orientalis, but old and large specimens can be very marbled on the underside, with virtually no red coloring left. Most of the animals in the North American pet trade come from a single region and will thus be P.granulosus. Since that is also the species which is most variable in color...color won't help much. This is the smallest and most elongate of the four species, though a large and fat animal might be hard to identify properly without a ruler and some MS-222.
That said...the pictures above leave me wondering, but I am still inclined to think the newt is elongate enough to easily be P.granulosus.
Regarding the name Pachytriton granulosus: This species was named many decades ago, based on juvenile animals from Zhejiang. I think those specimens were destroyed in WW2, which means all that remains is the published description, which includes good illustrations.Because juveniles differ in proportions, color, and skin texture, this species was later named to a new genus: Pingia. Subsequently, they were considered to just be juvenile torrent newts, and were thus dissolved first into P.brevipes, and later into P.labiatus.
Recently, it was discovered that larger, P.brevipes-like animals in Hunan were an anatomically distinct species, described as P.archospotus. This is not a new genus, but a new species. The dorsal color of this species is similar to most P.brevipes, though this is a color also found in Mt. Dapan animals and in some P.granulosus. The most distinctive feature is straight epibranchial bones, which give this species a longer head.
More recently, a small orientalis-like newt was discovered in Zhejiang. This was thought to be a distinct species, and was also thought to be the rediscovery of P.granulosus. The authors considered these to NOT be a Pachytriton, but a distinct genus, so they revalidated Pingia granulosa. Dubois and Raffaelli went further, considering this to be the same group of species as Cynops orphicus and Cynops orientalis. All three were moved to Hypselotriton (Pingia) [that's genus and subgenus]. I went one further, considering the orientalis group to be a full genus, Pingia. I still think that's the case, but Pingia is not the valid name for it, and Hypselotriton can safely be used still.
This is problematical. In even MORE recent studies, the redescribed specimens of Pingia granulosa couldn't be examined, but many new animals from the same area were. Those animals were found to be physically identical to Pingia granulosa. However, they were ALSO found to be juvenile Pachytriton, specifically the slender forms from the pet trade which have long been considered "northeastern labiatus". Examining the original description and illustration, it's obvious that the animals being described were the very same slender Pachytriton. By now it's clear that the spotted pachys are two species in the middle - P.brevipes and P.archospotus, and the two separate populations of brown [usually] pachys are also two species. The name P.labiatus belongs to the southwestern robust ones, while the slender northeastern ones include the animals names as P.granulosus.
Coming back to "problematical"...it's now clear we have four named species of torrent newt. Trouble is, someone has attached the name granulosus to new specimens which are PROBABLY juvenile torrent newts, but no-one else has actually examined them to be sure. The name might be falsely attached to a firebelly newt, and that needs to be confirmed and (if need be) fixed, including a new name for the firebelly (if that's what it is). The lesser remaining issue is that the coastal firebellies (Hypselotriton fudingensis, H.orientalis, H.orphicus, and potentially the so-called "granulosus") are left in need of a new subgenus or genus name, though as cousins of H.wolterstorffi they can continue to share that genus.
Summary:
Pachytriton archospotus
Pachytriton brevipes
Pachytriton granulosus
Pachytriton labiatus
Pachytriton A = P.granulosus
Pachytriton B = P.granulosus
Pachytriton C = Paramesotriton ermizhaoi
Pachytriton D [mine] = Paramesotriton sp.
Pachytriton D [others] = P.archospotus?
Hypselotriton (??) fudingensis
Hypselotriton (??) orientalis
Hypselotriton (??) orphicus
Pingia granulosa [original] = Pachytriton granulosus
"Pingia granulosa" [new] = Pachytriton granulosus or Hypselotriton (??) sp. nov.
but I did take pictures and one of them is decent. The object looked like a white developing embryo, somewhat curled at one end.
