Two new publications from the Caira lab on parasites, with vouchers deposited in the BRC collections:

1. Bernot J. P., J.N. Caira & M. Pickering. 2016. Diversity, phylogenetic relationships and host associations of Calliobothrium and Symcallio (Cestoda:‘Tetraphyllidea’) parasitising triakid sharks. Invertebrate Systematics 30: 616–634. pdf

Abstract reads: The laciniate, relatively large-bodied tetraphyllidean tapeworm genus Calliobothrium van Beneden, 1850 parasitises triakid sharks with all but one species found parasitising sharks of the genus Mustelus Linck, 1790. Historically, species of this genus were thought to exhibit a relaxed degree of host specificity relative to species of their sister genus Symcallio Bernot, Caira, & Pickering, 2015. However, several more recent studies have begun to question this difference and, in particular, the conspecificity of specimens identified as the types species, C. verticillatum (Rudolphi, 1819) van Beneden, 1850, from multiple host species. Our results suggest that diversity in the genus Calliobothrium has been under-reported. To explore this situation, specimens previously identified as C. verticillatum were collected from Mustelus asterias Cloquet, 1819 off the United Kingdom and Mustelus canis (Mitchell, 1815) off Connecticut, USA; these sharks each were found to host distinct species both of which are described here. Mustelus asterias was also confirmed to host Symcallio leuckarti (van Beneden, 1850) Bernot, Caira & Pickering, 2015, which is redescribed. In combination with newly collected material from Mustelus palumbes Smith, 1957 off South Africa and data available from GenBank, molecular phylogenetic analyses based on 28S rDNA data for four of the seven known species of Calliobothrium, including both new species and five of the 11 known species of Symcallio, were conducted. The resulting phylogeny supports the mutual monophyly of the two genera, which are readily distinguished based on whether they exhibit proglottid laciniations, and supports subclades of Symcallio with and without hook accessory pieces. These subclades of Symcallio appear to exhibit an intriguing congruence with two known subclades of their host genus, Mustelus.

 

2. Koontz A. & J.N. Caira. 2016. Emendation of Carpobothrium (“Tetraphyllidea”) from Bamboosharks (Orectolobiformes: Hemiscyliidae) with redescription of Carpobothrium chiloscyllii and description of a new species from Borneo. Comparative Parasitology 83: 149–161. pdf

Abstract reads: Collection of new material from the bamboosharks Chiloscyllium indicum (Gmelin, 1789) and Chiloscyllium hasseltii Bleeker, 1852, from Indonesian and Malaysian Borneo prompted reevalutation of the identity and host associations of the cestode genus Carpobothrium Shipley and Hornell, 1906. Light microscopical examination of whole mounts, histological sections, and egg preparations, in combination with scanning electron microscopy of scoleces, led to redescription of the type species Carpobothrium chiloscyllii Shipley and Hornell, 1906, from Ch. indicum, as well as description of a new species from Ch. hasseltii. The proglottid anatomy of C. chiloscyllii is described for the first time. The genus was confirmed to exhibit pouch-like bothridia with relatively small anterior and posterior flaps that have a tendency to retract into the bothridial pouches, testes that are entirely pre‐poral, a uterus that extends only to the cirrus sac, and a vas deferens that coils posterior to the cirrus sac. Although not previously reported for the genus, both species were determined to possess an apical sucker on the anterior margin of the anterior bothridial flap. The posterior coiling of the vas deferens allowed free gravid proglottids of the new Carpobothrium species to be distinguished from those of Yorkeria Southwell, 1927, and to determine that, while eggs of the former are spherical with bipolar filaments, those of the latter are spindle-shaped with unipolar filaments. Examination of some of Southwell’s material identified as C. chiloscyllii from the batoid hosts Urogymnus asperrimus Bloch and Schneider, 1801 and Rhynchobatus djeddensis Forsskål, 1775, in Sri Lanka, confirmed evidence from molecular work suggesting that these cestodes, which also bear pouch-like bothridia, represent a distinct group of cestodes from those parasitizing bamboosharks. This work both confirms the association of Carpobothrium species with sharks of the genus Chiloscyllium Müller and Henle, 1837, and paves the way for establishment of a novel genus for the taxa parasitizing batoids

Nicolas Magain who visited UCONN while working on his Master’s thesis (via the uNiversity of Liège, Belgium) and then completed his dissertation project on symbiotic associations within the lichen forming fungal genus Peltigera, published his main chapter:  Magain N., J. Miadlikowska, B. Goffinet, E. Sérusiaux, & F. Lutzoni. 2017. Macroevolution of specificity in cyanolichens of the genus Peltigera Section Polydactylon (Lecanoromycetes, Ascomycota). Systematic Biology 66: 74–99. pdf

The study is based on numerous specimens from the CONN herbarium.

Abstract reads: Patterns of specificity among symbiotic partners are key to a comprehensive understanding of the evolution of symbiotic systems. Specificity of mutualistic partners, within a widespread monophyletic group for which all species are sampled has rarely been explored. Here, we assess the level of specificity between the cosmopolitan lichen-forming fungus (mycobiont) from the genus Peltigera, section Polydactylon, and its cyanobacterial partner Nostoc (cyanobiont). The mycobiont and cyanobiont phylogenies are inferred fromfive nuclear loci and the rbcLX region, respectively. These sequences were obtained from 206 lichen thalli, representing ca. 40 closely related Peltigera species sampled worldwide, doubling the number of known species in this group. We found a broad spectrum of specificity for both partners ranging from strict specialists to generalists. Overall, mycobionts aremore specialized than cyanobionts by associating mostly with one or a few Nostoc phylogroups, whereas most cyanobionts associate frequently with several Peltigera species. Specialist mycobionts are older than generalists, supporting the hypothesis that specialization of mycobionts to one or few cyanobionts, is favored through time in geographic areas where species have been established for long periods of time. The relatively recent colonization of a new geographic area (Central and South America) by members of section Polydactylon is associated with a switch to a generalist pattern of association and an increased diversification rate by the fungal partner, suggesting that switches to generalism are rare events that are advantageous in new environments. We detected higher genetic diversity in generalist mycobionts. We also found that Peltigera species specialized on a single Nostoc phylogroup have narrower geographical distributionscompared with generalist species.