Prionotropis rhodanica Uvarov, 1923

Massa, Bruno, Ünal, Mustafa & Verde, Gabriella Lo, 2015, Revision of the genus Prionotropis Fieber, 1853 (Orthoptera: Pamphagidae: Thrinchinae), Zootaxa 4059 (3), pp. 499-524 : 508-509

Prionotropis rhodanica Uvarov, 1923 , resurrected status

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:42808

Material examined. France, Rhone delta VII.1920 (♂ holotype, 3♀ paratypes); France, Rhone delta, Crau VI.1919, P. Marchal (8♀); France, Rhone delta, Crau VI.1921, P. Marchal (2♀); France, Rhone delta, La Crau VII.1949, C. de Vichet (9♂, 8♀); France, Rhone delta, La Crau VII.1947, Delmas (1♂, 1♀); France, Rhone delta 28.VII.1953, A. Rambier (2♂, 1♀); France, Rhone delta, St. Martin de Crau 22.VI.1990 and 22.VI.1991, A.

Foucart (2♂, 2♀) ( MNHN); France, Rhone delta, 12.VII.1991, A. Foucart (3♂, 3♀) ( CBGP); France, Crau Dist., Bouches du Rhône, P.R. Fowe (1♂, 1♀ paratypes); France, Bouches du Rhône, Martin de Crau 24.VI.1991, A. Foucart (4♂, 5♀) (NHM); France, Crau, ex Delmas (1♂, 1♀) ( MSNG).

Remarks and distribution. The distribution of P. rhodanica is very interesting because it covers a very narrow area of the Rhone river (Crau), ca. 50 km from the area of Var, where the other taxon P. a z am i lives (see below). When they were discovered, both P. rhodanica and P. az a m i were considered to be disjoint populations of the Balkanic P. h ys t ri x ( Chopard 1922). However, Uvarov (1923) found differences between the two populations and named them P. hystrix azami and P. hystrix rhodanica respectively, but later he raised P. rhodanica to species level, and maintained azami as subspecies of hystrix ( Uvarov 1943) . Also Harz (1975) followed this arrangement, while Foucart (1995), finding a wide variability within the populations of the three taxa, proposed to consider again azami and rhodanica subspecies of P. h ys t ri x, as in the initial view of Uvarov (1923). The same arrangement has been maintained by Streiff et al. (2002, 2005). Finally, Defaut & Morichon (2015) have proposed to consider the specific taxon P. rhodanica , with two subspecies, rhodanica and azami .

Morphological differences between P. rhodanica and P. a z ami. P. rhodanica is clearly more dorsoventrally compressed, and its pronotal carina is less raised than in P. az a m i. This produces a shorter projection of fore margin of the pronotum and a less pronounced angle of hind margin of the pronotum in P. rhodanica , compared to P. a z am i. Tegmina of males of P. rhodanica exceed the 3rd tergite, females the 2nd tergite, while those of males of P. az a m i just exceed the 2nd tergite, and females just cover the 1st tergite. In addition the spines of abdominal tergites of P. rhodanica are shorter than spines of P. az a m i, every spine covering only ¼ in P. rhodanica , and 1/3 of the following tergite in P. az a m i. In this respect, P. rhodanica and P. hyst rix are more similar than with P. a z am i. Both P. rhodanica and P. a z am i have less evident spines on the upper margin of the hind femora, compared to P. hystrix . Concerning the genitalia, they are very similar, both in the shape of the epiphallus and penis valves; in P. rhodanica pseudolophi of epiphallus are more disorderly placed, while in P. azami are more regularly placed (Figs 6, 7, 14, 15, 22, 23, 30, 31, 35, 36, 39, 40, 46, 47, 54, 55).

From the genetic point of view, Streiff et al. (2005) found that genetic diversity at eight microsatellite loci was highly structured, indicating substantial isolation of populations of the two taxa living in the area of the Rhone delta; genetic drift was the major force involved in the genetic structure, with very little gene flow at the regional scale, consistent with both the limited dispersal of this flightless species and the patchy configuration of its habitat. The authors were unable to find significant differences in the extent of genetic diversity and concluded that the two taxa have to be considered as subspecies of P. hystrix . However, Streiff et al. (2005) gave information on the population genetic structure, they worked on microsatellites, that did not give phylogenetical information, but only information on relationships among individuals, and consequently on the structure and distance among groups and populations. They found the presence of shared loci and alleles between the two taxa, but this does not provide information about taxa identification. Thus, as significant morphological differences were found during our research both between distant (e.g., P. hystrix and P. a z am i) and near populations (e.g., P. az a m i and P. rhodanica ) we consider that raising them to the species level is justified. Based on the considerations reported above, we propose to consider P. rhodanica a valid species, separated from both P. az a m i and P. h ys t ri x.

Measurements. see Table 1 . Biometric ratios of males resulted different from all other species, while those of females lie within the group azami / hystrix / flexuosa , with the exclusion of the ratio length of tegmina of males/length of tegmina of females for the latter ( Figs 65–68 ).

Conservation of the taxon. This taxon is listed as Critically Endangered on the IUCN Red List since 2012, is protected by French Legislative text of 3rd August 1979 (Protection of Insects in France), and its distribution area lies within the Coussouls de Crau Nature Reserve since 2004 ( Foucart 1995, Foucart et al. 1999). Considering it a species will have quite strong consequences for its conservation and ongoing conservation projects.

Figures

FIGURES 65 – 66. Biometrics of the genus Prionotropis. Ratio length of pronotum / length of hind femora (PL / HFL), length of hind femora / length of tegmina (HFL / TGL), length of pronotum / length of tegmina (PL / TGL) and total length of body / length of tegmina (TL / TGL) in males (65) and in females (66) of Prionotropis appula, P. willemsorum n. sp., P. rhodanica, P. azami, P. hystrix, P. flexuosa, and P. maculinervis.

FIGURE 67. Scatterplot of the first two factors resulting from the PCA analysis of biometrics of Prionotropis appula, P. willemsorum n. sp., P. rhodanica, P. azami, P. hystrix, its synonym P. sontiaca, P. maculinervis and P. flexuosa males (a) and females (b).

FIGURE 68. Length of tegmina of males and females of Prionotropis appula, P. willemsorum n. sp., P. rhodanica, P. azami, P. hystrix, P. flexuosa and P. maculinervis.