ISSN 10623604, Russian Journal of Developmental Biology, 2015, Vol. 46, No. 4, pp. 196–207. © Pleiades Publishing, Inc., 2015.
Original Russian Text © A.A. Makhrov, I.Yu. Popov, 2015, published in Ontogenez, 2015, Vol. 46, No. 4, pp. 240–251.
Related forms that have different life cycles and,
therefore, differ in ecology and morphology, have been
the object of studies by not only experts in develop
mental biology but also ecologists and evolutionists for
decades (Aleev, 1986; Sharov, 1987; Bruton, 1989;
Roff, 1992; Stearns, 1992; Schluter, 2000; Dgebuadze
2001; WestEberhard, 2003). To define these forms, a
number of terms (life forms, ecological forms, life
strategies, discrete adaptive norms, ecomorphs, life
history styles, alternative phenotypes, etc.) are used.
In terms of studying the evolution, of great interest is
the fact of origination of one form from another, signif
icantly different in the ontogenetic characteristics. This
fact is also a challenge for taxonomists, because the
individuals belonging to different species but having
identical life cycles often look more similar than the
individuals belonging to the same species but having
different life cycles. Suffice it to recall the anadromous
individuals and dwarf males of salmonids, which were
even described as different species. At the same time,
representatives of the same life form, such as Atlantic
) and brown trout (
have a great resemblance (for a review, see Makhrov,
A similar situation is observed in lampreys. Their
ontogeny includes the larval stage, which lasts for sev
eral years. The larvae live in muddy ground at the bot
tom of rivers and streams, feeding on various micro
scopic organisms. After metamorphosis, the morphol
ogy and lifestyle of lampreys greatly change. The best
known are two variants of the life cycle of lampreys.
The “resident” lampreys after metamorphosis stop
feeding, reproduce, and die. The “anadromous” lam
preys after metamorphosis migrate to the sea, where
they actively feed and significantly increase in size.
Thereafter, they return to freshwater to spawn and
then die. In most cases, the anadromous lampreys lead
a parasitic lifestyle, feeding on fish blood; however,
they can also be scavengers and eat invertebrates.
In the majority of lamprey genera, both of these life
forms are known; they were described as separate spe
cies. However, there are parasitic and nonparasitic res
ident species, which are morphologically very similar.
For the latter, the special term “paired species” was
proposed (Zanandrea, 1959b). Later, to define two or
more closely related forms of lampreys, one of which
is parasitic, the term “satellite species” was introduced
(Vladykov and Kott, 1979b) (table).
In addition to the objective reasons, the taxonomy
is influenced by subjective causes. The variety of con
cepts of the species (see the monograph by Coyne and
Orr, 2004) allows substantiating almost any stand
point. However, the number of objective criteria that
can be used to distinguish species is not as great. The
latter include the presence of diagnostic morphologi
cal and genetic traits, as well as prezygotic and postzy
gotic reproductive isolation. Some authors also use the
geographic species criterion.
The objective of our work was to apply these criteria
to the forms of lampreys differing in the life cycle char
acteristics, which, in turn, makes it possible to esti
mate the evolutionary significance of the differences in
Life Forms of Lampreys (Petromyzontidae) as a Manifestation
of Intraspecific Diversity of Ontogenesis
A. A. Makhrov
and I. Yu. Popov
Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences,
Leninskii pr. 33, Moscow, 119071 Russia
St. Petersburg State University, 16 liniya VO 29, St. Petersburg, 199178 Russia
Received August 17, 2014; in final form, January 18, 2015
—Some lamprey genera include forms that have significantly different life cycles (the most well
known are the “anadromous” and “resident,” or the “parasitic” and “nonparasitic” forms). The analysis of
data on the genetic characteristics of these forms shows that, in some cases, the nonparasitic lampreys inde
pendently derived from the parasitic ones in different aqueous systems. These data, together with the results
of morphological analysis as well as data on the distribution, ecology, hybridization, and observations of joint
spawning of parasitic and nonparasitic forms, show that these forms belong to the same species (except the
resident forms that were isolated long ago).
: ontogeny, lampreys, evolution, genetics, hybridization, species