Heteromysis S. I. Smith, 1873

Daneliya, Mikhail E., 2021, On the Mysid Crustacean Genus Heteromysis (Mysidae: Heteromysinae) of the Tasman Sea, with Notes on the Tribe Heteromysini, Records of the Australian Museum (Rec. Aust. Mus.) 73 (1), pp. 1-50 : 6-7

Heteromysis S. I. Smith, 1873

Heteromysis S. I. Smith, 1873 (issued in 1874): 553; 1879: 101.—G. O. Sars, 1882 (issued in 1883): 55; 1885: 11, 172, 173, 216.— Norman, 1892: 147, 158.—Holt & W. M. Tattersall, 1906a: 10.—W. M. Tattersall, 1908: 32; 1922: 495; 1927a: 236, 253; 1927b: 185, 195; 1951: 235.—W. M. Tattersall & O. S. Tattersall, 1951: 72, 414.— Zimmer, 1909: 48, 140.— Hansen, 1910: 5, 7, 8; 1925: 110.— Illig, 1930: 599.— Calman, 1932: 128, 131.— Fage & Monod, 1936: 110, 111.— Nouvel, 1940: 3, 4; 1949: 3; 1957: 331; 1964: 37, 38.— Nouvel et al., 1999: 44, 53, 54, 75, 79.— Băcescu, 1941: 35−36; 1968: 221, 222, 225, 226, 231, 234−236; 1970: 15, 16; 1975: 41; 1976: 86, 89−91; 1979: 143, 144, 146; 1983: 7, 8, 11; 1986: 93, 94.— Băcescu & Bruce, 1980: 67, 71.— Băcescu & Iliffe, 1986: 99, 100.— Băcescu & Ortiz, 1984: 22.— Banner, 1948: 67, 106.— Clarke, 1955: 7−11.—O. S. Tattersall, 1949: 450; 1955: 141; 1961: 145, 156; 1962: 222−236; 1965: 17, 19; 1967: 161, 162, 164−167, 203, 208, 211.— Pillai, 1961: 32; 1965: 1725; 1968: 47−51.— Ii, 1964: 282, 568.— Brattegard, 1969: 96, 98; 1970: 129, 130, 133, 136, 143, 147, 151; 1980: 50.— Mauchline & Murano, 1977: 58.— Lagardère & Nouvel, 1980: 376, 873.— Mauchline, 1980: 36.— Bowman, 1981: 458.— Modlin, 1984: 283; 1987a: 296; 1987b: 116, 120; 1987c: 653.— Fenton, 1986: 8, 15, 24, 141, 162, 191.— Kathman et al., 1986: 24, 163.— Murano, 1988: 46; 1998: 31.— Murano & Hanamura, 2002: 75.— Murano & Fukuoka, 2003: 185.— Ledoyer, 1989: 41.— Escobar-Briones & Soto, 1990: 131; 1991: 85, 87.— Bowman & Orsi, 1992: 738, 739.— Müller, 1993: 218.— Vannini et al., 1993: 190, 192; 1994: 137.— Bravo & Murano, 1996: 483.— Wittmann, 1996: 229; 2000: 279, 280, 284, 286, 287; 2001: 93, 104, 105; 2004: 782; 2008: 352, 360, 367−370; 2013: 505; 2020: 141−143, 151, 156.— Wittmann et al., 2014: 213, 214, 231, 235, 253, 270, 309−311, 324, 341, 405.— Wittmann & Chevaldonné, 2016: 1, 7.— Wittmann & Wirtz, 2017: 143, 146, 148.— Wittmann & Griffiths, 2017: 16, 17, 39−42.— Wittmann &Abed-Navandi, 2019: 81, 82, 92−95; 2021: 133−138, 159, 170−172.— Bamber, 2000a: 129, 133; 2000b: 57, 58.— Price & Heard, 2000: 88; 2008: 143, 147; 2011: 33, 37, 43.— Price et al., 2018: 2, 8.— Hanamura & Kase, 2001a: 11, 12, 15, 17, 19; 2001b: 70.— Hanamura et al., 2012: 11, 12.— Fukuoka, 2004: 1353, 1354, 1359, 1366, 1369.— Daneliya, 2012: 135, 136.— Chevaldonné et al., 2014: 1, 6−7.—Noёl et al., 2014: 30, 55.— San Vicente & Monniot, 2014: 333, 334, 338−340.— Lavesque et al., 2016: 2, 3, 4.— Pérez et al., 2016: 306.— Ortiz & Lalana, 2017: 71, 74, 76.

[Non Heteromysis Czerniavsky, 1882: 57 , 62 (junior homonym)].

Chiromysis G. O. Sars, 1877: 56 .—Hilgendorf, 1878 (issued in 1879): 845, partim [synonymized with Heteromysis by S. I. Smith, 1879: 101; mentioned as valid in Kossmann, 1880: 92; Czerniavsky, 1882: 16, 58, 63; mentioned as synonym of Heteromysis in G. O. Sars, 1885: 216].

Type species. Heteromysis formosa S. I. Smith, 1873 , by monotypy.

Diagnosis. Body moderately robust, not notably compressed dorsoventrally.Abdominal segments without pleurites. Telson trapezoidal, with apical cleft; its spinules not exceptionally long. Eyes with cornea; eyestalk without distolateral lobe. Antennular peduncle distomedial setae not directed backwards; male process without posteromedial lobe. Pereopod 1 carpopropodus with medial spiniform or other modified setae. Pereopod 2 carpopropodus multisegmented. Pereopods 3−6 preischium without process; ischium without flagellated spiniform setae. Penes without large apical lobes, tubular. Females without sternal plate projecting behind marsupium. Uropodal endopod with spiniform setae.

Comparison. The genus Heteromysis has no unique characters shared by all of its members. The structure of the pereopod 1 carpopropodus, previously considered as distinguishing Heteromysis from other genera, although shared by the congeners, is also found in other genera. It is most similar to Ischiomysis , Platymysis and Retromysis . Ischiomysis differs by the presence of the acute process on the preischium of the pereopod 6, the flagellated spiniform setae on its ischium, and the penes with the large apical lobes (all three features missing in Heteromysis ). Platymysis has a dorsoventrally compressed body and the abdominal pleurites (not compressed and the pleurites absent in Heteromysis ), its eyestalk with the prominent distolateral lobe (absent in Heteromysis ) and the pereopod 1 carpopropodus with seemingly secondarily fused segments (the distal segment is at a different stage of reduction, but always present in Heteromysis ). Retromysis differs by the distomedial setae of the antennular peduncle, directed backwards (forward in Heteromysis ), the presence of the posteromedial lobe on the male process (absent in Heteromysis ) and the sternal plate projecting behind the marsupium (absent or not projecting in Heteromysis ). Even a combination of these three or any other heteromysine genera does not produce common unique features. In contrast, rather clearly defined groups are found within Heteromysis , recognized as subgenera.

Remarks. Comparing Heteromysis with all described heteromysine genera, I attempted here to re-diagnose the genus to include only characters common for all species and distinguish them from representatives of other genera. The following characters are no longer considered diagnostic: the size and general shape of the eyes, the size of the processus masculinus, the shape and length of the antennal scale, the presence of the sternal processes, and the number of the oostegites.

The concept of the pereopod 1 of G. O. Sars (1877), as defined earlier, with 1-segmented carpopropodus, was followed after O. S. Tattersall (1967) by various authors ( Brattegard, 1969, 1970, etc.; Modlin, 1984, 1987a, b, c; Fenton, 1986; Murano & Hanamura, 2002; Murano & Fukuoka, 2003). Some scholars followed Smith’s concept (S. I. Smith, 1874) of the 2-segmented carpopropodus and illustrated the distinct dactylus as separate from the unguis and the second segment of the carpopropodus (e.g., Pillai, 1961, plate 6N; Băcescu, 1979, fig. 1O,N; 1986, fig. 1O,P; Wittmann, 2000, figs 11, 12; 2001, fig. 3B; 2008, figs 1l, m, 4j, k; 2020, fig. 4A,D,G,K,Q; Wittmann et al., 2014, figs 54.18H, 54.35F, G; Wittmann & Chevaldonné, 2017, fig. 2A, B; Wittmann & Wirtz, 2017, figs 3D,E, Wittmann & Griffiths, 2017, fig. 4A,B, etc.; Fukuoka, 2004, fig. 2C; Hanamura et al., 2012, fig. 1g; Price & Heard, 2011, fig. 2C; Price et al., 2018, fig. 3C). As can be seen from the illustrations in the current work ( Figs 2F , 7B , 10G , 14H , 19C , 24D ), the dactylus, occupies the proximal part of what was considered a dactylar claw. The border between the dactylus and the dactylar claw is recognized by the typical small distomedial setae. I therefore confirm that the propodus (or more correctly the carpopropodus) of Heteromysis consists of two segments.

The nominate subgenus, Heteromysis , has been a heterogeneous catch-all that contained species that did not belong to any of the three other known subgenera. Based on a detailed comparison of the pereopod 1 endopod and the antennular peduncle, particularly in new material from the Tasman Sea, a well-defined group of species can be established within the subgenus Heteromysis s. str. Many species of Heteromysis have been described rather inadequately, and the possible taxonomic status of this group can only be defined after re-examination of a better preserved material across the genus.

Distribution and Habitat. Cosmopolitan. In-shore, shallow water (upper sublittoral). The characteristic ecological feature of Heteromysis is commensalism ( Nouvel et al., 1999).

Life history. Nouvel (1940) observed copulation in H. formosa , which took place at night and immediately after the molting of the female and the liberation the young from the brood pouch. During copulation a male took position under a female, head to tail and the ventral surface to the ventral surface, and clasping thoracopods around the abdomen; the penis was inserted between the marsupial plates and the sperm ejected into the marsupial chambers. Only two eggs develop in the marsupium.

Composition. To date 105 species are known in the genus Heteromysis . From them 82 species are divided between four subgenera: Heteromysis (Heteromysis) , Heteromysis (Gnathomysis) Bonnier et Perez, 1902 , Heteromysis (Neoheteromysis) Băcescu, 1976 , and Heteromysis (Olivemysis) Băcescu, 1976 , among which three subgenera Heteromysis , Gnathomysis and Olivemysis are found in the Tasman Sea. The remaining species have been described from incomplete specimens or rather inadequately, and their subgeneric assignment in still pending.

Figures

Figure 2. Heteromysis (H.) communis, male, 4 mm,AM P.98680.(A) maxilla 1, anterior; (B) maxilla 2, anterior; (C) maxilliped 1, anterior; (D) maxilliped 2, posterior; (E) pereopod 1 endopod, posterior; (F) distal part of pereopod 1 endopod, anterior; (G) distal part of pereopod 1 endopod, posterior; (H) pereopod 2 endopod, anterior; (I) pereopod 3, posterior; (J) distal part of pereopod 3 endopod, posterior. Scales (mm): A, F, G, J = 0.25; B−E, H, I = 0.5.

Figure 7. Heteromysis (Heteromysis) keablei sp. nov. (A, C, F) holotype, male, 4.5 mm, AM P.75281; (B, D, E) paratype, male, 4.5 mm, AM P.98693. (A) pereopod 1 endopod, posterior; (B) pereopod 1 endopod, posterior; (C) distal seta of pereopod 1 carpopropodus segment 2; (D) distolateral seta of pereopod 1 carpopropodus segment 1; (E) posterolateral seta of pereopod 1 carpopropodus segment 1; (F) pereopod 3. Scales (mm): A, F = 0.5; B = 1; C−E = 0.25.

Figure 10. Heteromysis (Heteromysis) macropsis, female, 4 mm, AM P.98707. (A) mandibular palp, medial; (B) labrum, ventral; (C) maxilla 1, posterior; (D) maxilla 2, posterior; (E) maxilliped 2 endopod, anterior; (F) pereopod 1 endopod, anterior; (G) distal part of pereopod 1 endopod, anterior; (H) pereopod 2 endopod, anterior; (I) distal part of pereopod 2 endopod, anterior. Scales (mm): A−F, H = 0.5; G, I = 0.25.

Figure 14. Heteromysis (Heteromysis) tasmanica, female, 6 mm, AM P.36618. (A) mandibular palp, medial; (B) labrum, ventral; (C) mandible, left; (D) maxilla 1, anterior; (E) maxilla 2, anterior; (F) maxilliped 1 endopod, posterior; (G) maxilliped 2 endopod, anterior; (H) pereopod 1 endopod, anterior; (I) distal seta of pereopod 1 carpopropodus segment 2; (J) distal cuspidate setae of pereopod 1 carpopropodus segment 1. Scales (mm): A, E−H = 0.5; B−D, I = 0.25; J = 0.1.

Figure 19. Heteromysis (Olivemysis) abrucei Băcescu, 1979, male, Tasman Sea, New South Wales, Port Kembla, AM P.63480. (A) maxilliped 1, anterior; (B) maxilliped 2 endopod, posterior; (C) pereopod 1 endopod, posterior; (D) distolateral spiniform setae (one side) of pereopod 1 carpopropodus segment 1, posterior. Scales (mm): A−C = 0.5; D = 0.25.

Figure 24. Heteromysis (Olivemysis) murrayae sp. nov. (A−F) holotype, female, 7 mm, AM P.98685; (G) paratype, female, 7 mm, New South Wales, Forster, AM P.98687. (A) maxilla 2, posterior; (B) maxilliped 1 endopod, posterior; (C) maxilliped 2 endopod, posterior; (D) pereopod 1, posterior; (E) distolateral spiniform setae of pereopod 1 carpopropodus segment 1, posterior; (F) pereopod 2 endopod, posterior; (G) pereopod 2 endopod, posterior. Scales (mm): A, C, D, F, G = 0.5; B, E = 0.25.