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(C and D) Dark morph Dolomedes gregoric sp. nov.: (C) A female (KPARA00250) in hunting pose on water; (D) a male (KPARA00248) placed on a white background. (E–F): D. bedjanic sp. nov.: (E) A female (KPARA00129) on a rock in a stream; (F) a male (KPARA00234) on shallow water under vegetation. (A and B) Dark morph Dolomedes kalanoro Silva & Griswold, 2013: (A) A female (KPARA00184) on a rock in a river; (B) a male (KPARA00185) at a river bank. (G and H) White banded morph D. kalanoro: (G) A male (KAPAR00227) hiding in a dead tree above a river during day time; (H) a female carrying an egg sac hiding in a tree trunk near a river during day time. (I) White banded morph D. gregoric sp. nov. (Holotype male, USNMENT01580825) on a tree trunk near a river. (J and K) Dolomedes hydatostella sp. nov.: (J) A female (KPARA00163) in a shallow understory swamp; (K) a male (KPARA00258) placed on a white background. (L and M) D. rotundus sp. nov.: (L) A female (KPARA00243), and (M) a male (KPARA00236) in a shallow part of a stream. Yu & Kuntner. 2024. DOI: 10.7717/peerj.16781 |
Abstract
Madagascar is a global biodiversity hotspot, but its biodiversity continues to be underestimated and understudied. Of raft spiders, genus Dolomedes Latreille, 1804, literature only reports two species on Madagascar. Our single expedition to humid forests of eastern and northern Madagascar, however, yielded a series of Dolomedes exemplars representing both sexes of five morphospecies. To avoid only using morphological diagnostics, we devised and tested an integrative taxonomic model for Dolomedes based on the unified species concept. The model first determines morphospecies within a morphometrics framework, then tests their validity via species delimitation using COI. It then incorporates habitat preferences, geological barriers, and dispersal related traits to form hypotheses about gene flow limitations. Our results reveal four new Dolomedes species that we describe from both sexes as Dolomedes gregoric sp. nov., D. bedjanic sp. nov., D. hydatostella sp. nov., and D. rotundus sp. nov. The range of D. kalanoro Silva & Griswold, 2013, now also known from both sexes, is expanded to eastern Madagascar. By increasing the known raft spider diversity from one valid species to five, our results merely scratch the surface of the true Dolomedes species diversity on Madagascar. Our integrative taxonomic model provides the framework for future revisions of raft spiders anywhere.
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| Dolomedes species collected from humid forests in the east and the north of Madagascar, showing the habitus coloration and variation. (A and B) Dark morph D. kalanoro Silva & Griswold, 2013: (A) A female (KPARA00184) on a rock in a river; (B) a male (KPARA00185) at a river bank. (C and D) Dark morph D. gregoric sp. nov.: (C) A female (KPARA00250) in hunting pose on water; (D) a male (KPARA00248) placed on a white background. (E–F): D. bedjanic sp. nov.: (E) A female (KPARA00129) on a rock in a stream; (F) a male (KPARA00234) on shallow water under vegetation. (G and H) White banded morph D. kalanoro: (G) A male (KAPAR00227) hiding in a dead tree above a river during day time; (H) a female carrying an egg sac hiding in a tree trunk near a river during day time. (I) White banded morph D. gregoric sp. nov. (Holotype male, USNMENT01580825) on a tree trunk near a river. (J and K) D. hydatostella sp. nov.: (J) A female (KPARA00163) in a shallow understory swamp; (K) a male (KPARA00258) placed on a white background. (L and M) D. rotundus sp. nov.: (L) A female (KPARA00243), and (M) a male (KPARA00236) in a shallow part of a stream. |
Kuang-Ping Yu and Matjaž Kuntner. 2024. Discovering unknown Madagascar Biodiversity: Integrative Taxonomy of Raft Spiders (Pisauridae: Dolomedes) PeerJ. 12:e16781. DOI: 10.7717/peerj.16781
