Ambrysus stali La Rivers

Sites, Robert W. & Reynoso-Velasco, Daniel, 2015, Review of the Ambrysus stali La Rivers species complex (Heteroptera: Nepomorpha: Naucoridae) with the description of a new species from Mesoamerica, Zootaxa 4018 (2), pp. 279-291 : 287-289

Ambrysus stali La Rivers

( Figs. 1 , 6 )

Ambrysus stali La Rivers 1962 : Bull. S. Cal. Acad. Sci. Bull. 185–187. Ambrysus bourquini De Carlo 1968 : Rev. Soc. Entomol. Arg. 100.

Discussion. La Rivers (1962) considered this species to be closely related to A. oblongulus and presented characteristics to distinguish them. The male accessory genitalic process of tergum VI ( Fig. 6 B) is slightly narrower than in other members of the A. stali complex, although intraspecific variation is evident. Also distinctive is that the longitudinal stripes of the pronotum are less linear and more coalescent than in other members of the complex, and the hemelytra are uniformly brown or dark brown without lighter mottling ( Fig. 6 A).

Reported here are the first records of A. stali from Guyana. Nieser (1975) indicated that this species is common in Suriname and occurs in small, shaded streams where it occurs in "barriers of branches and trees in moderate to quite strong currents (3– over 10 m /min.)", and less commonly at the margins on vegetation and debris.

In papers concerning the fauna of Argentina, López Ruf (1987, 2007) and Mazzucconi et al. (2009) indicated the presence of A. stali in Misiones Province, which is in the northeastern part of the country. López Ruf (2007) also provided a description of egg structure of the Argentina population. We have been unable to confirm their identifications because voucher specimens are not present at Museo de La Plata or Museo Argentino Ciencias Naturales. An undescribed species of Ambrysus occurs nearby in Paraguay that bears superficial resemblance to the A. stali complex; however, male genitalic features indicate that it is clearly does not belong to this complex.

Because the Argentina records are widely separated from all other records of the species and a similar species occurs in that region, we suspect that the Argentina material is probably not conspecific with A. stali . Type locality. FRENCH GUIANA, St. Laurent. Holotype is housed at CAS.

Material examined., FRENCH GUIANA: St. Laurent [du Maroni], October 1937, H. E. Hinton, Cal. Acad. Sci. Coll. / Ira La Rivers Collection, Bequeathed to the California Academy of Sciences—1978 / California Academy of Sciences Type No. 13412 / Ambrysus stäli La Rivers HOLOTYPE (♂, CAS). GUYANA: REGION 9, Parabara, elev 274 m, 2º 6' 29.52", -59 º13' 39.183", 3 November 2013, Short, Isaacs, Salisbury / GY–1103–02A, Small flowing creek with sand-detritus margins & leaf packs-stick jams (2♂, 2♀, UMC); Kusad Mts., Basecamp, 2.811917, - 59.866833, 163, 23 October 2013, A. E. Short, small sandy stream with detritus, GY 13–1023–01 A (1♂, 1–5th instar, UMC); Region 9, Kusad Mts., Basecamp, 2.811917, -59.866833, 163 m, 23 October 2013, A. E. Short, pool in mostly dried streambed GY 13–1023–02 A (1♂, UMC); N. Parabara, creek by basecamp (Bototo wau creek), 2.181800, - 59.338432, 289 m, 31 October 2013, Short, Isaacs, Salisbury, stream margins, GY 13-1031-01 A (1♂, 1♀, UMC). SURINAME: SIPALIWINI, Camp 1, Kutari river, 2°10.973'N, 56°47.235'W, 238 m, 22 August 2010, Short & Kadosoe, forest swamp, SR10-0822-02A (1♂, 2♀, UMC); Camp 1, Kutari river, 2.175350, -56.787399, 228 m, 20 August 2010, Short & Kadosoe, forest stream, SR10-0820-01A (4♂, UMC); Camp 4 (low): Kasikasima, 2.977310, - 55.384998, 200 m, 20 March 2012, A. E. Short, sandy stream, SR12-0320-02A (2♂, UMC); Central Suriname Nature Reserve: Tafelberg Summit, near Augustus Creek Camp, 3.926667, -56.188332, 600 m, 17 August 2013, Short & Bloom, forested detrital pools and creeks on trail into Arrowhead basin, SR13-0817-01A (1♀, UMC); Central Suriname Nature Reserve, Tafelberg Summit, near Augustus Creek Camp, 3.926667, -56.188332, 600 m, 17 August 2013, SR13–0817–03A (4♂, 5♀, UMC); Central Suriname Nature Reserve, Tafelberg Summit, near Caiman Creek Camp, 3.899033, -56.180817, 733 m, 19 August 2013, Short & Bloom, Caimen Creek, pools and creek margins, SR13-0819-04B (1♂). TRINIDAD: bet. Four Roads & Carmichael, 5 VII 2005, 220 ft, unnamed stream, 10º30'N, 61º13'W / (underside of same label) WDS-A-1647 / William D. Shepard, leg. (1♂, 1♀, UMC).

Published records. La Rivers (1962): BRAZIL, Pará; FRENCH GUIANA, St. Laurent [du Maroni]; [ SURINAME]; TRINIDAD. La Rivers (1972), Nieser (1975): BRAZIL, Amazonas and Pará states; SURINAME, Brokopondo, Marowijne, and Saramacca Districts. Araujo & Beserra (2007): VENEZUELA, Amazonas.

Figures

FIGURE 1. Distribution of species in the Ambrysus stali species complex.

FIGURE 6. Structures of Ambrysus stali. (A) dorsal habitus of male, (B) 6 th and 7 th abdominal terga of male, (C) ventral and left sides of phallosoma, (D) 8 th abdominal tergum showing medial pseudoparameres, (E) terminal abdominal sterna of female showing subgenital plate with posterior and lateral margins outlined in black (setae have been removed to reveal shape).