Progenetic species in polychaetes (Annelida) and problems assessing their phylogenetic affiliation.
نویسنده
چکیده
Progenesis is defined as the retention of ancestral juvenile characters by adult stages of descendants due to an acceleration of the sexual maturation and thus is often regarded as a fast evolutionary process. Several small, meiofaunal polychaetes, such as Dinophilidae, some "Dorvilleidae" (for example, Parapodrilus), and Protodrilida, exhibit morphological simplicity in that they lack features typical of larger polychaetes, for example, parapodia and/or head appendages. Due to the general resemblance of adult meiofaunal polychaetes to juveniles of larger forms, progenesis has been invoked to explain evolutionary origins of many smaller taxa with increasing frequency over the past 4 decades. In this review, I summarize the interstitial species of polychaetes for which progenetic origin has been suggested on the basis of morphology. However, critical examination of morphological data that includes larval features reveals that autapomorphic characters uniting supposed progenetic taxa to specific annelid lineages are often missing. Typically larval and juvenile characters, which are argued to support hypotheses of progenetic origin, are often widely dispersed, homoplastic features. Because of this situation, molecular data seem to be the most reliable source for phylogenetic inference. However, other biological data, for example, from life history and morphology, are necessities to substantiate the progenetic evolution of these species.
منابع مشابه
The use of polychaetes (Annelida) as indicator species of marine pollution: a review
Polychaetes are usually the most abundant taxon in benthic communities and have been most often utilized as indicator species of environmental conditions. This review finds that, while the use of indicator species for a particular pollutant is not simple, polychaetes can provide a useful means of assessing the effects of poor environmental conditions. Polychaetes may be used as sensitive monito...
متن کاملDinophilidae (Annelida) is most likely not a progenetic Eunicida: evidence from 18S and 28S rDNA.
Dinophilidae (e.g., Dinophilus O. Schmidt, 1848) is a typical meiofaunal polychaete taxon with a seemingly simple organisation, e.g., no parapodia, only a few segments (Rouse and Pleijel, 2001). Dinophilidae is thought to be an eunicidan taxon and is often presented as the classical example of progenetic evolution within annelids (Westheide, 1987). The retention of ancestral juvenile characters...
متن کاملPolychaetes as Annelid Models to Study Ecoimmunology of Marine Organisms
Annelids are among the first coelomates and are therefore of special phylogenetic interest. They constitute an important part of the biomass of the seashore, estuaries, fresh water and terrestrial soils. Moreover, they occupy a central position in the trophic networks, as a major food source for fishes, birds and terrestrial fauna. Among Annelids, the large majority of polychaetes is restricted...
متن کاملMicroRNAs resolve an apparent conflict between annelid systematics and their fossil record.
Both the monophyly and inter-relationships of the major annelid groups have remained uncertain, despite intensive research on both morphology and molecular sequences. Morphological cladistic analyses indicate that Annelida is monophyletic and consists of two monophyletic groups, the clitellates and polychaetes, whereas molecular phylogenetic analyses suggest that polychaetes are paraphyletic an...
متن کاملEcology and biology of chemoreception in polychaetes
Nervous system and sensory structure morphologies provide useful information for reconstructing phylogenetic relationships among the Polychaeta, Annelida, and Arthropoda. With the more common use of indirect immunocytochemistry and laser scanning confocal microscopy methods, the detailed information available from morphological studies has increased. Despite this wealth of information, developi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Integrative and comparative biology
دوره 46 4 شماره
صفحات -
تاریخ انتشار 2006