Berosus interstitialis Knisch, 1924

Deler-Hernandez, Albert, Fikacek, Martin & Cala-Riquelme, Franklyn, 2013, A review of the genus Berosus Leach of Cuba (Coleoptera, Hydrophilidae), ZooKeys 273, pp. 73-106 : 81-84

Berosus interstitialis Knisch, 1924 Figures 4 a–g 11

Berosus tessellatus Fletiaux & Sallé, 1889: 337 (secondary homonym of Enoplurus tessellatus Motschulsky, 1859).

Berosus (s.str.) interstitialis Knisch, 1924: 270. - Van Tassell 1966: 191 (unpublished PhD thesis: redescription, identification key). - Epler 2010: 12.24 (taxonomic notes).

Berosus stribalus Orchymont, 1946: 13. Syn. n. - Spangler 1981: 156 (taxonomic and distribution notes). - Fernández et al. 2010: 28 (checklist).

Type locality.

Guadeloupe, Grande Terre and Trois-Rivières.

Type material examined.

Berosus tessellatus :Not examined. Type specimens were not found on our request for loan in MNHN. Instead, we examined the specimens identified as Berosus tessellatus and Berosus interstitialis deposited in coll. d’Orchymont and coll. Knisch in IRSNB (see below).

Berosus stribalus : Holotype: male (IRSNB): "[male sign] / Cuba 10. K / S. of Pinar Rio / Sep. 12-23 '13 // A. d’Orchymont det. / Berosus (s.str.) / stribalus m. // Type". Paratype: 1 spec. (IRSNB): "St. / Domin- / go // Berosus / striatus / Say // coll. Orch. // A. d’Orchymont det. / Berosus (s.str.) / stribalus m. // Para- / type".

Additional material examined.

CUBA: Isla de la Juventud: 4 exs. (dry-mounted) (CZACC): vii.1960 [no locality and collector indicated]; 8 exs. (in alcohol) (BSC-E): Punta del Este, laguna temporal [temporal pool], 21°33'43"N, 82°33'18"W, 1 m a.s.l., 21.v.2006, leg. Y. S. Megna, 00180; 8 exs. (in alcohol) (BSC-E): Laguna Cayamás, 21°33'43"N, 82°33'18"W, 3 m a.s.l., 23.v.2006, leg. Y. S. Megna, 00178. Pinar del Río: 57 exs. (dry-mounted) (CZACC): Lomas de Soroa, v/vi.1963, [no collector indicated]; 1 ex. (in alcohol) (BSC-E): Viñales, arroyo [stream], 22°33'36.35"N, 83°49'59"W, 170 m a.s.l., 18.iv.2012, leg. A. Deler-Hernández, 00146. Artemisa:8 exs. (dry-mounted) (CZACC): Laguna Ariguanabo, vi.1963, [no collector indicated]. Mayabeque:1 ex. (dry-mounted) (CZACC): Jibacoa, littoral on north coast, v.1962, [no collector indicated]. Matanzas:1 ex. (dry-mounted) (CZACC): Playa Larga, iv.1965, [no collector indicated]; 1 ex. (dry-mounted) (CZACC): Bacunayagua, vi.1940 [no collector indicated]. Camagüey:1 ex. (in alcohol) (BSC-E): Sierra de Cubitas, Río El Roble, 21°32'53.23"N, 77°46'42.31"W, 55 m a.s.l., 14.iv.2012, leg. A. Deler-Hernández, 00148. Las Tunas:1 ex. (in alcohol) (BSC-E): Amancio, Comunales, laguna permanente [permanent pool], 20°49'59"N, 77°32'32"W, 34 m a.s.l., 04.x.2008, leg. Y. S. Megna, 00179; 1 ex. (in alcohol) (BSC-E): La Fé, laguna temporal [temporal pool], 20°49'17.7"N, 77°34'40.8"W, 50 m a.s.l., 18.xii.2008, leg. Y. S. Megna, 00147. Granma: 2 exs. (in alcohol) (BSC-E): Cauto Cristo, laguna permanente [permanent pool], 20°33'33.1"N, 76°28'44"W, 44 m a.s.l., 04.i.2005, leg. L. Chávez, 00150; 1 ex. (dry-mounted) (NMPC): Cauto Cristo, permanent lagoon 20°33'33.1"N, 76°28'44"W, 44 m a.s.l., 04.i.2005, leg. L. Chávez. Santiago de Cuba:1 ex. (in alcohol) (BSC-E): Guamá, La Mula, laguna permanente [permanent pool], 19°58'33.6"N, 76°46'4.8"W, 4 m a.s.l., 20.vi.2008, leg. A. Deler-Hernández, 00018. Guantánamo:1 ex. (dry-mounted) (CZCTR): Guantánamo, San Carlos [at light], 20°26'22"N, 74°42'31"W, 160 m a.s.l., 18.vii.1915, leg. C. T. Ramsden; 1 ex. (dry-mounted) (CZCTR): San Carlos [at light], 20°26'22"N, 74°42'31"W, 160 m a.s.l., 24.viii.1917, leg. C. T. Ramsden; 1 ex. (in alcohol) (BSC-E): San Antonio del Sur, Macambo, Río Macambo, 20°03'26.9"N, 74°44'15"W, 4 m a.s.l., 24.x.2008, leg. A. Deler-Hernández; 1 ex. (in alcohol) (BSC-E): Baracoa, Nibujón, laguna temporal [temporal pool], 20°30'8.6"N, 74°38'88"W, 8 m a.s.l., 03.ii.2010, leg. A. Deler-Hernández, 00149. 1 ex. (dry-mounted) (IRSNB): [without precise locality]:"Cuba / Gundlach // 1541 / 977 // Kniž det. / interstitialis". GUADELOUPE: 1 ex. (dry-mounted) (IRSNB): "Guadeloupe / coll. A. d’Orchymont // Berosus s.str. / tessellatus / Fleut. & Salle // A. d’Orchymont det." [based on attached note, d’Orchymont compared this specimen with one of the types of Berosus tessellatus from the collection of Fleutiaux which is currently lost and not available for reexamination; the specimen is a male, but has the abdomen destroyed by a dermestid larva]; 1 ex. (dry-mounted) (IRSNB): Trois Riviéres, leg. Dufau. PUERTO RICO: 1 ex. (dry-mounted) (IRSNB): [without detailed locality data], leg. Moritz. VIRGIN ISLANDS: 2 exs. (dry-mounted) (IRSNB): Saint Thomas, leg. C. Felsche.

Published Cuban records:Pinar del Río: Entronque de Manuel Sanguili ( Spangler 1981). Isla de la Juventud: Laguna Base Julio Antonio Mella ( Spangler 1981). Holguín: Gibara, Arroyo Landivar at Finca Pozón ( Spangler 1981). Santiago de Cuba: Matías ( Spangler 1981).

Diagnosis.

Habitus as in Figs 4a, b. Body length 5.0-5.3 mm. Head uniformly dark, metallic green; pronotum pale with a pair of closely aggregated longitudinal nar row dark spots mesally; elytra pale with darkened punctation and with dark spots in anterior and posterior third of intervals 1 and 2, in humeral area and at midlength of intervals 7-9, plus with variable number of spots on remaining intervals. Elytral apices entire in both sexes. Mesoventral process laminar, with small anterior tooth projecting ventrad, nearly straight middle portion and rounded posterior part (Fig. 4c). Abdominal ventrite 1 with median keel developed only between metacoxae. Emargination of ventrite 5 deep, subrectangular, with two slender medial teeth (Fig. 4g), not showing sexual dimorphism. Aedeagus (Figs 4 d–f) strongly compressed from sides; parameres ca. 2 × as long as phallobase, wide throughout in lateral view except for tooth-like apex; bases of the parameres in dorsal view with characteristic basal teeth.

Taxonomic note.

The synonymy of Berosus stribalus with Berosus interstitialis was first proposed in an unpublished thesis by Van Tassell (1966: 302). The reasons for the synonymy were not explained, and Cuba (i.e. type locality of Berosus stribalus ) was not even mentioned in the distribution of Berosus interstitialis in the taxonomic part of the thesis. We were not able to examine the types of Berosus tessellatus from the collection of Fleutiaux in MNHN as the specimens were not found. We therefore examined the specimens identified as Berosus tessellatus and Berosus interstitialis deposited in IRSNB, including one male from Guadeloupe (type locality of Berosus tessellatus ) bearing the note that it was compared with the types of Berosus tessellatus by A. d’Orchymont. Comparison of these specimens with the types of Berosus stribalus and with newly collected Cuban specimens revealed that they all specimens agree in the diagnostic characters mentioned above, including the characteristic shape of the aedeagus and a characteristic tooth on the base of each paramere. We may therefore confirm the unpublished synonymy proposed by Van Tassell (1966) and consider Berosus stribalus as a junior subjective synonym of Berosus interstitialis .

Habitat.

Cuban specimens were collected mainly in standing waters as well as in isolated pools along streams and rivers in the lowlands. The localities are usually exposed to sun and have turbid water, muddy bottom, submerged vegetation and are rich in organic matter.

Distribution.

Widely distributed Caribbean species, so far recorded from the Bahamas, Haiti Guadeloupe, Virgin Islands Puerto Rico and Cuba ( Van Tassell 1966, Orchymont 1946, Epler 2010, this paper). The species is here recorded for the first time from Cuba, due to the synonymy of Berosus stribalus with Berosus interstitialis .