Doubt about the taxonomic status of subspecies in both of the wild camelids of South America

@michaelweymann @michalsloviak @tonyrebelo @geichhorn @jwidness @jakob

There are two species of wild camelids in South America, namely the vicuna (Vicugna vicugna, and the guanaco (Lama guanicoe,

In both,

  • there is sexual monomorphism, with so little difference in appearance between male and female that the sexes are hard to distinguish in the field,
  • the intraspecific variation is mainly latitudinal (north-south),
  • body size is considerably smaller in northern than in southern forms, and
  • the distributions are wide enough that subspecies have been postulated.

However, in both species, the question of subspeciation remains somewhat puzzling and unresolved.

In the case of the vicuna, there is no problem recognising the two subspecies, which look so different that raising them to the status of different species (Groves and Grubb 2011) seems reasonable.

What has not previously been pointed out is that the two subspecies differ categorically in a way.

The northern subspecies has conspicuous colouration overall, whereas the southern subspecies does not ( Furthermore, confusion of identity, in which photos of the vicuna on the Web are mislabelled as the guanaco, occurs only in the case of V. v. vicugna.

However, the puzzle is how the two subspecies have remained distinct, despite the lack of a geographical barrier between them.

Vicugna vicugna vicugna and Vicugna vicugna mensalis live in similar landscapes, and under similarly extreme (high-altitude) climates. One merely replaces the other on a south-north basis - so abruptly that there seems to be no zone of natural intergradation.

In the case of the guanaco,

  • the northern and southern forms are as not as consistently different as in the case of the vicuna - despite the greater latitudinal span involved, and
  • there is more individual variation, within any given population, than in the case of the vicuna.

(What has not previously been pointed out is that the vicuna is one of the least individually variable of ungulates, all adult members within each subspecies appearing virtually identical once the effects of intermittent wool-shearing by humans are taken into account.)

In the guanaco the intraspecific variation seems too patchy and irregular to allow identification of subspecies on the basis of either appearance or region. A clinal, as opposed to subspecific, system of variation seems plausible.

The following is a closer scrutiny of subspecific variation in the two species.


The northern subspecies of the vicuna, viz. Vicugna vicugna mensalis, is easily recognised by virtue of its frontal bleeze, centred on the chest:

The pale pelage in the southern subspecies of the vicuna, viz. Vicugna vicugna vicugna, emphasises the hips instead of the chest. However, it is not particularly conspicuous in either of these parts of the body: (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web) (mislabelled on the Web)


In the case of the guanaco:

Previous descriptions, in the literature, of the difference between northern and southern forms of the guanaco ( seem inept/incomplete/misleading.

This because

  • it has been claimed that the northernmost subspecies, namely Lama guanicoe cacsilensis, tends to be relatively pale - which is not borne out by the many photos on the Web, from Peru and northern Chile,
  • a major point has been overlooked, viz. that the pale tracts on the posterior flanks and on the buttocks are poorly-developed, and
  • a minor point has been overlooked, viz. that the dark on the head extends relatively far to the posterior, including the ear pinnae in some individuals.

The following are the northernmost 44 observations of the guanaco in iNaturalist, west of the Andes, all of which would presumably fall within subspecies cacsilensis: (apparently hybridised with Lama glama)

What these photos reveal is a relatively uniform colouration, with a ground-colour that is not noticeably pale in most individuals. In these populations, most of the pale features of the species are relatively poorly-developed, disqualifying what I have referred to as

  • a lateral bleeze,
  • a frontal bleeze,
  • a posterior bleeze/flag, and
  • a laryngeal flag.

Furthermore, the head is consistently and extensively rather dark, the darkness extending to the ear pinnae in some individuals.

At the other (southern) extreme of the distribution of the guanaco lies the island of Tierra del Fuego (

The many observations in iNaturalist from Tierra del Fuego can be seen in These all fall within the nominate subspecies, guanicoe.

Within these sets of photos, the clearest comparison is between



This confirms that the main difference between the northern and southern forms is the extension of the ventral pale pelage on to the flanks (constituting a lateral bleeze) in the latter.

Although this difference seems obvious, I have yet to see it pointed out in the literature. This omission may be partly because terms such as 'blaze', 'bles', and 'bleeze' are too specialised to be applied to general descriptions. However, by stating that it is the northern form that is the paler overall, previous authors have, in a sense, inverted the real relationship.

Although adapted to arid to semi-arid climates, the northern form of the guanaco is not pallid in the way so familiar in mammals and birds of deserts. It is, instead, better-described as relatively plain-coloured for its species.

Based on the consistent difference between northern and southern forms of the guanaco in the absence/presence of a lateral bleeze, I would have no objection to recognising these as valid subspecies, namely cacsilensis and nominate guanicoe. However, it remains possible that the variation is clinal (on a latitudinal basis), rather than subspecific.

Furthermore, it remains unclear how the remaining two postulated subspecies, namely voglii (Bolivia and northwestern Argentina) and huanacus (central Chile), relate to the colouration illustrated here.

It would make sense for voglii (east of the Andes) to differ from huanacus (west of the Andes), because they are separated by a formidable geographical barrier. However, clear differences among the three forms, cacsilensis, voglii (, and huanacus (, have yet to be demonstrated.

A strong case can be made - based partly on the lack of any cline/intergradation - for the recognition of Vicugna vicugna vicugna as a species separate from what is currently regarded as subspecies mensalis. It is, therefore, ironic that this relatively plain-coloured southern form of the vicuna is not only seldom appreciated for its distinctiveness, but it is frequently misidentified as the northern, relatively plain-coloured form of the guanaco.

This confusion, which is an embarrassment on the Web, results partly from the fact that both V. v. vicugna (high altitudes) and L. g. cacsilensis (low altitudes) occur in the Atacama region (in a sense broader than the low-altitude desert,

Publicado el 18 de febrero de 2023 08:11 por milewski milewski


NORTHERN FORM OF GUANACO (subspecies cacsilensis):

Publicado por milewski hace 10 meses
Publicado por milewski hace 10 meses
Publicado por milewski hace 10 meses

The following footage shows that, in the guanaco in Tierra del Fuego, the lateral bleeze occurs in most or all individuals:

Publicado por milewski hace 10 meses


Publicado por milewski hace 10 meses

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