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Hoplitolyda duolunica gen. et sp. nov. (Insecta, Hymenoptera, Praesiricidae), the Hitherto largest sawfly from the Mesozoic of China.

Gao T, Shih C, Rasnitsyn AP, Ren D - PLoS ONE (2013)

Bottom Line: Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction.Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure.Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Capital Normal University, Beijing, China.

ABSTRACT

Background: Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction. Hymenopterans, most being phytophagous or parasitic, have a relatively small to medium body size, typically under 50.0 mm in body length.

Principal findings: Herein, we describe Hoplitolyda duolunica gen. et sp. nov., assigned to Praesiricidae, from the Early Cretaceous Yixian Formation of China. This new species is the largest fossil hymenopteran hitherto with body estimated >55.0 mm long and wing span >92.0 mm. H. duolunica is, to our knowledge, the only sawfly with Sc present in the hind wing but not in the forewing. Its Rs1 and M1 meeting each other at 145° angle represents an intermediate in the transition from "Y" to "T" shapes. Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure.

Conclusions/significance: Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc. Considering the reported ferocious predators of feathered dinosaurs, pterosaurs, birds, and mammals coexisting in the same eco-system, Hoplitolyda is an interesting case of "survival of the fittest" in facing its evolutionary challenges.

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Transition of wing venation from “Y” shape to “T” shape in Pamphilioidea.A, Aulidontes mandibulatus Rasnitsyn, 1983; B, Juralyda udensis Rasnitsyn, 1977; C, Hoplitolyda duolunica gen. et sp. nov.; D, Praesirex hirtus Rasnitsyn, 1968; E, Rudisiricius crassinodus Gao, Rasnitsyn, Ren & Shih, 2010; F, Rudisiricius celsus Gao, Rasnitsyn, Ren & Shih, 2010.
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pone-0062420-g004: Transition of wing venation from “Y” shape to “T” shape in Pamphilioidea.A, Aulidontes mandibulatus Rasnitsyn, 1983; B, Juralyda udensis Rasnitsyn, 1977; C, Hoplitolyda duolunica gen. et sp. nov.; D, Praesirex hirtus Rasnitsyn, 1968; E, Rudisiricius crassinodus Gao, Rasnitsyn, Ren & Shih, 2010; F, Rudisiricius celsus Gao, Rasnitsyn, Ren & Shih, 2010.

Mentions: An evolutionary trend is revealed by the sections of Rs and M in the course of formation of the so-called basal vein (red in Fig. 4) as represented by a series of sawfly fossils. Plesiomorphically, as shown by most Xyelidae, Rs1 and M1 meet each other at an acute or right angle (forming a “Y” shape together with Rs+M), and this character state is apparently lost in all Pamphilioidea, mainly as a byproduct of shortening of Rs1 (Fig. 4). The most basal case can be found in A. mandibulatus (Fig. 4A) [3], while the other fossils show a transition (Figs 4B–D) [1], [25] toward a perfectly linear alignment of Rs1 and M1 (Figs 4E, F) (forming a “T” shape together with Rs+M) [4], which is the (true) basal vein present in a majority of Hymenoptera Apocrita [8], [26]. The new genus represents an intermediate position in the transition from “Y” to “T” shapes. The well-developed basal vein is probably important aerodynamically. In general, wing structures suggest that H. duolunica sp. nov. was a good flyer, although not an excellent one.


Hoplitolyda duolunica gen. et sp. nov. (Insecta, Hymenoptera, Praesiricidae), the Hitherto largest sawfly from the Mesozoic of China.

Gao T, Shih C, Rasnitsyn AP, Ren D - PLoS ONE (2013)

Transition of wing venation from “Y” shape to “T” shape in Pamphilioidea.A, Aulidontes mandibulatus Rasnitsyn, 1983; B, Juralyda udensis Rasnitsyn, 1977; C, Hoplitolyda duolunica gen. et sp. nov.; D, Praesirex hirtus Rasnitsyn, 1968; E, Rudisiricius crassinodus Gao, Rasnitsyn, Ren & Shih, 2010; F, Rudisiricius celsus Gao, Rasnitsyn, Ren & Shih, 2010.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643952&req=5

pone-0062420-g004: Transition of wing venation from “Y” shape to “T” shape in Pamphilioidea.A, Aulidontes mandibulatus Rasnitsyn, 1983; B, Juralyda udensis Rasnitsyn, 1977; C, Hoplitolyda duolunica gen. et sp. nov.; D, Praesirex hirtus Rasnitsyn, 1968; E, Rudisiricius crassinodus Gao, Rasnitsyn, Ren & Shih, 2010; F, Rudisiricius celsus Gao, Rasnitsyn, Ren & Shih, 2010.
Mentions: An evolutionary trend is revealed by the sections of Rs and M in the course of formation of the so-called basal vein (red in Fig. 4) as represented by a series of sawfly fossils. Plesiomorphically, as shown by most Xyelidae, Rs1 and M1 meet each other at an acute or right angle (forming a “Y” shape together with Rs+M), and this character state is apparently lost in all Pamphilioidea, mainly as a byproduct of shortening of Rs1 (Fig. 4). The most basal case can be found in A. mandibulatus (Fig. 4A) [3], while the other fossils show a transition (Figs 4B–D) [1], [25] toward a perfectly linear alignment of Rs1 and M1 (Figs 4E, F) (forming a “T” shape together with Rs+M) [4], which is the (true) basal vein present in a majority of Hymenoptera Apocrita [8], [26]. The new genus represents an intermediate position in the transition from “Y” to “T” shapes. The well-developed basal vein is probably important aerodynamically. In general, wing structures suggest that H. duolunica sp. nov. was a good flyer, although not an excellent one.

Bottom Line: Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction.Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure.Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Capital Normal University, Beijing, China.

ABSTRACT

Background: Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction. Hymenopterans, most being phytophagous or parasitic, have a relatively small to medium body size, typically under 50.0 mm in body length.

Principal findings: Herein, we describe Hoplitolyda duolunica gen. et sp. nov., assigned to Praesiricidae, from the Early Cretaceous Yixian Formation of China. This new species is the largest fossil hymenopteran hitherto with body estimated >55.0 mm long and wing span >92.0 mm. H. duolunica is, to our knowledge, the only sawfly with Sc present in the hind wing but not in the forewing. Its Rs1 and M1 meeting each other at 145° angle represents an intermediate in the transition from "Y" to "T" shapes. Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure.

Conclusions/significance: Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc. Considering the reported ferocious predators of feathered dinosaurs, pterosaurs, birds, and mammals coexisting in the same eco-system, Hoplitolyda is an interesting case of "survival of the fittest" in facing its evolutionary challenges.

Show MeSH