Heteromysis (Olivemysis), Bacescu, 1968

Wittmann, Karl J. & Abed-Navandi, Daniel, 2021, Four new species of Heteromysis (Crustacea: Mysida) from public aquaria in Hawaii, Florida, and Western to Central Europe, European Journal of Taxonomy 735, pp. 133-175 : 137-143

Subgenus Olivemysis Băcescu, 1968

Olivemysis Băcescu, 1968: 237 (defined in key).

Olivaemysis – Băcescu 1970: 11–16 (incorrect subsequent spelling); 1981: 85 (evolution). —Hanamura & Kase 2001: 17 (expressed doubt on subgenus concept).

Olivemysis – Bowman & Orsi 1992: 739 (definition in key). — Bravo & Murano 1996: 483 (in key). — Wittmann 2008: 368–370 (revalidated spelling, etymology). — Price & Heard 2011: 43–44 (first formal diagnosis). — San Vicente & Monniot 2014: 341 (taxonomy, in key).

Type species

Heteromysis (Olivemysis) rubrocincta Băcescu, 1968 , by monotypy.

Species inventory

A total of 39 species, including the new ones, is given in the key below. For 30 species see list in Price & Heard (2011). Nine species of this subgenus described after 2011 are H. cocoensis Price , Heard & Vargas, 2018; H. domusmaris Wittmann & Abed-Navandi, 2019 ; H. ekamako Wittmann & Chevaldonné, 2017 ; H. hornimani sp. nov.; H. ningaloo Daneliya, 2012 ; H. sabelliphila Wittmann & Wirtz, 2016 ; H. sixi sp. nov.; H. smithsoniana sp. nov. and H. waikikensis sp. nov.

Definition

Definition of subgenus modified after Price & Heard (2011), using present terminology, mainly in order to receive Heteromysis sixi sp. nov.: bifid flagellate spine, usually directed disto-mesially, and long, unbranched seta directed disto-laterally on disto-mesial edge of the antennular trunk; thoracic endopod 3 prehensile, moderately robust, some of the distal articles enlarged; disto-mesial edge of merus 3 not serrated, without tooth-like extension; propodus 3 mostly without paradactylary setae but, if any, representing small, simple setae; some of male pleopods 1–5 (in most species including pleopod 4), if any, modified by flagellate spines (or by attenuated setae); endopod of uropods shorter than exopod. Secondary diagnostic features are present in most species: eyestalks with disto-mesial process (tooth, tubercle), and male thoracic sternites with median processes.

Morphological note

Twelve out of a total of 35 previously known species here acknowledged as pertaining to this subgenus, have male pleopod 2 and additional pleopods modified. Male pleopod 2 is also modified in the four new species of Heteromysis , including two species with pleopod 2 modified also in females. These four species also share disto-mesial teeth on eyestalks and median processes on male thoracic sternites.

Key to species of the subgenus Olivemysis Băcescu, 1968

The subgeneric assignment is here explicitly indicated for all 39 acknowledged species of Olivemysis . An additional 13 species given below are insufficiently known and therefore so far not assigned to any subgenus.

1. Lateral margins of telson armed with spines along most of proximal half and beyond.................... 2

– Lateral margins of telson armed with spines only on distal half or at most on distal ¾.................. 24

2. Lateral margins of telson armed with continuous series of spines, all along or at least along the stretch reaching from 1/5 to 4/5 distance from the basis (not counting the apical spines) ................... 3

– Lateral margins of telson armed with spines in basal and (sub)-terminal portions except for a smooth stretch in between ............................................................................................................................ 18

3. Telson cleft with laminae along <4/5 of its margins, distally remaining portion smooth .................. 4

– Telson cleft with laminae along ± 4/5 of its margins......................................................................... 10

4. Endopod of uropod with spines only on proximal half ..................................................................... 5

– Endopod of uropod with spines on proximal and on (entire or part of) distal half ........................... 8

5. Disto-mesial edge of antennular trunk with inconspicuously flagellate, large, robust spine, 0.7 times length of mesial margin of terminal segment of trunk; endopod of uropod with 5 spines ...................................................................... H. (O.) kensleyi Modlin, 1987 (Gulf of Mexico)

– Disto-mesial edge of antennular trunk with well-flagellate, blade-like spine; blade measured without flagellum <0.6 times as long as mesial margin of terminal segment of trunk; endopod of uropod with <5 spines ........................................................................................................................................... 6

6. Male pleopods 2–4 with 4–5, 8–14, and 21–28 flagellate spines, respectively, and female pleopod 2 with 2–4 flagellate spines, remaining pleopods with normal setae only; telson cleft with 18–22 laminae...................................................................................................................................... H. (O.) hornimani sp. nov. (public aquaria in Western to Central Europe: London, Paris, Brest and Wroclaw)

– Pleopod 2 without spines in both sexes; male pleopod 4 with 5–11 modified spines; telson cleft with 10–20 laminae.................................................................................................................................... 7

7. Male pleopod 3 with 3–5 attenuated spines, male pleopod 4 with 5–6 attenuated spines; thoracic endopod 3 with carpopropodus length <2 times width; telson cleft with 10–16 laminae .................. .............................................................................. H. (O.) modlini Price & Heard, 2011 (Caribbean)

– Male pleopod 3 with 11 flagellate spines, male pleopod 4 with 17 flagellate spines; thoracic endopod 3 with carpopropodus length>2 times width; telson cleft with about 20 laminae .............................. .......................................................................................... H. (O.) abrucei Băcescu, 1979 ( Australia)

8. Endopod of uropods with 5–6 spines; lateral margins of telson with 9–10 spines.............................. ............................................................. H. (O.) guitarti Băcescu, 1968 (Caribbean, Gulf of Mexico)

– Endopod of uropods with 8–15 spines; lateral margins of telson with 18–24 spines........................ 9

9. Endopod of uropods with 13–15 spines; lateral margins of telson with 18–21 spines........................ ............................................................................... H. (O.) essingtonensis Murano, 1988 ( Australia)

– Endopod of uropods with 8–10 spines; lateral margins of telson with 20–24 spines.......................... ................................................................................... H. (O.) siciliseta Brattegard, 1970 (Caribbean)

10. Disto-mesial edge of antennular trunk with modified (mostly flagellate) spine in addition to setae ..................................................................................................................................................11

– Disto-mesial edge of antennular trunk without modified spines, with whip setae in addition to normal setae ................................................................................................................................................. 17

11. Endopod of uropods with 2 spines................................................................................................... 12

– Endopod of uropods with 3–5 spines............................................................................................... 13

12. Lateral margins of telson with 18–19 spines; telson cleft with 25 laminae..................................... 23

– Lateral margins of telson with 15–16 spines; telson cleft with 12 laminae......................................... ............................................................................................. H. (O.) agelas Modlin, 1987 ( Bahamas)

13. Lateral margins of telson with 10–12 spines; telson cleft with 23–31 laminae; endopod of uropod with 4 spines.......................................................... H. (O.) quadrispinosa Murano, 1988 ( Australia)

– Lateral margins of telson with> 14 spines ...................................................................................... 14

14. Lateral margins of telson with <19 spines ...................................................................................... 15

– Lateral margins of telson with ± 19 spines ...................................................................................... 16

15. Telson cleft with 18–20 laminae; endopod of uropods with 5 spines; flagellate spine on disto-mesial edge of antennular trunk terminally with tubercles ............................................................................. ............................................................................. H. (O.) tuberculospina Modlin, 1987 (Caribbean)

– Telson cleft with 22–24 laminae; endopod of uropods with 3–4 spines; flagellate spine on distomesial edge of antennular trunk without tubercles ......... H. waitei W.M. Tattersall, 1927 ( Australia)

16. Lateral margins of telson with 19–20 spines; telson cleft with 31 laminae......................................... .................................... H. bredini Brattegard, 1970 (only 1 ♀ known) (Caribbean, Gulf of Mexico)

– Lateral margins of telson with 24–25 spines; telson cleft with about 35 laminae............................... ............................................................ H. (O.) maxima Murano, 1998 (only 1 ♂ known) ( Australia)

17. Endopod of uropods with 1 spine; carpopropodus of thoracic endopod 3 with 9–10 strong spines; telson cleft with 16–18 laminae.............. H. panamaensis O.S. Tattersall, 1967 (E Pacific: Panama)

– Endopod of uropods with 4 spines; carpopropodus of thoracic endopod 3 with 3–7 strong spines; telson cleft with 30 laminae.................................................. H. odontops Walker, 1898 (NE Pacific)

18. Telson cleft with laminae along basal <4/5 of its margins ............................................................... 19

– Telson cleft with laminae along basal ± 4/5 of its margins ............................................................... 23

19. Antennal sympod with spiniform extension on outer face; eyestalks with field of scales on mesial margin; basal and median segments of antennular trunk each with dorsal apophysis bearing modified setae (spines) plus normal setae; merus of thoracic endopod 3 with series of 4–6 unilaterally barbed setae on rostral face; only male pleopods 3–4 modified by flagellate spines; endopod of uropods with 2–6 spines along inner margin............................................................................. H. (O.) domusmaris Wittmann & Abed-Navandi, 2019 (tanks of the Haus des Meeres Aquarium in Vienna, Austria)

– Antennal sympod without or with terminally rounded extension on outer face; basal and median segments of antennular trunk without dorsal apophysis (unknown in H. zeylanica ); eyestalks without field of scales on mesial margin....................................................................................................... 20

20. Endopod of uropods with 3–4 spines near statocyst; merus of thoracic endopod 3 without unilaterally barbed setae ..................................................................................................................................... 22

– Endopod of uropods with 7–11 spines along inner margin ............................................................. 21

21. Exopod of uropods with modified, sickle-shaped seta subapically on outer margin; merus of thoracic endopod 3 with 4 unilaterally barbed setae on lateral margin ............................................................. ............................................................ H. disrupta Brattegard, 1970 (only 1 ♀ known) (Caribbean)

– Exopod of uropods with normal setae only; merus of thoracic endopod 3 without unilaterally barbed setae; only male pleopods 3–4 modified by flagellate spines .............................................................. .................................................... H. (O.) zeylanica W.M. Tattersall, 1922 (Indian Ocean, Australia)

22. Thoracic endopods 5–8 with 6-segmented carpopropodus; male pleopods 2–4 modified by flagellate spines .................................................................. H. (O.) macrophthalma Băcescu, 1983 ( Australia)

– Thoracic endopods 5–8 with 7-segmented carpopropodus ................................................................. ......................................................... H. (O.) ningaloo Daneliya, 2012 (only 1 ♀ known) ( Australia)

23. Endopod of uropods with 2 spines near statocyst; 6 spines on basal third of lateral margins of telson............................................................................ H. (O.) sexspinosa Murano, 1988 ( Australia)

– Endopod of uropods with 13 spines along inner margin; 2 spines on basal third of lateral margins of telson................................................................... H. singaporensis O.S. Tattersall, 1967 ( Singapore)

24. Telson cleft with laminae along ± 4/5 of its margins......................................................................... 36

– Telson cleft with laminae along <4/5 of its margins, distally remaining portion smooth ................ 25

25. Telson elongate with constriction at ⅔ length from basis, telson length 2–3 times maximum width near basis, lateral margins concave; uropods without spines; telson cleft 16% telson length; cleft proximally with 2–3 laminae ...................................... H. filitelsona Modlin, 1984 (Gulf of Mexico)

– Telson without lateral constriction .................................................................................................. 26

26. Endopod of uropods without spine; carpopropodus of thoracic endopod 3 with 3 strong spines; apical cleft> ¼ telson length; cleft with about 25 laminae................................................................. .............................................. H. gymnura W.M. Tattersall, 1922 (N Indian Ocean: Gulf of Manaar)

– Endopod of uropods with> 1 spine................................................................................................. 27

27. Endopod of uropods with 2–5 spines............................................................................................... 30

– Endopod of uropods with> 5 spines ............................................................................................... 28

28. Endopod of uropods with 6–9 spines............................................................................................... 31

– Endopod of uropods with> 9 spines ............................................................................................... 29

29. Endopod of uropods with 11–19 spines........................................................................................... 33

– Endopod of uropods with 40–45 spines; carpopropodus of thoracic endopod 3 with 4 spines; apical cleft 0.2–0.3 times as long as telson; cleft with 8–13 laminae ........................................................... ......................................................................... H. (O.) actiniae Clarke, 1955 (Caribbean, Bahamas)

30. Endopod of uropods with 2–3 spines near statocyst; carpopropodus of thoracic endopod 3 with 6–7 flagellate spines; male pleopod 2 ending in a large, non-flagellate spine............................................ .............................. H. (O.) ekamako Wittmann & Chevaldonné, 2016 (Central Pacific: Marquesas)

– Endopod of uropods with 5 spines near statocyst; carpopropodus of thoracic endopod 3 with 8–9 flagellate spines; male pleopod 2 not modified, without spines ......................................................... ................................................................................ H. (O.) coralina Modlin, 1987 (Gulf of Mexico)

31. Endopod of uropods with 6–7 spines on proximal half; apical cleft 1/5 telson length; cleft with 10–14 laminae; male pleopods 3–4 with 3 and 4 flagellate spines, respectively ........................................... ....................................................................................... H. (O.) mariani Băcescu, 1970 (Caribbean)

– Endopod of uropods with 9 spines on proximal ⅔; apical cleft 3/10 telson length, cleft with 15–17 laminae; male pleopod 4 with 20–29 flagellate spines .................................................................... 32

32. Pleopod 2 not modified in both sexes; male pleopod 3 with 6–7 stout, robust, plumose (i.e., not flagellate) setae along distal margin; male pleopod 4 with 20 flagellate spines; carpopropodus of thoracic endopod 3 with 4 pairs of flagellate spines; lateral margins of telson with 9–12 spines ....................................................................... H. (O.) beetoni Modlin, 1984 (Gulf of Mexico)

– Male pleopod 2 with 3 smooth, tooth-like spines; pleopod 3 with 20 flagellate spines, pleopod 4 with 29 flagellate spines; carpopropodus of thoracic endopod 3 with 6 flagellate spines; lateral margins of telson with 11–13 spine ....................................................................................................................... .................. H. (O.) tenuispina Murano, 1988 (only adult male and immature ♀ known) ( Australia)

33. Apical cleft 0.4–0.5 times telson length, cleft with 6–11 laminae; endopod of uropods with 14–19 spines; male pleopod 4 with about 26 flagellate spines....................................................................... ....................................................... H. (O.) floridensis Brattegard, 1969 (Gulf of Mexico, Bahamas)

– Apical cleft 0.2–0.3 times telson length; lateral margins of telson with 5–9 spines; only male pleopod 4 modified ........................................................................................................................................ 34

34. Male pleopod 4 with 2–9 flagellate spines; telson cleft with 6–10 laminae; carpopropodus of thoracic endopod 3 with 5–6 spines ................................ H. (O.) ebanksae Price & Heard, 2008 (Caribbean)

– Male pleopod 4 with> 25 spines; telson cleft with 11–20 laminae; carpopropodus of thoracic endopod 3 with 6–7 flagellate spines................................ H. (O.) bermudensis G.O. Sars, 1885 (35)

35. Telson cleft with 15–20 laminae; distal margin of male pleopod 4 with about 35–55 flagellate spines ............................ H. (O.) bermudensis bermudensis G.O. Sars, 1885 ( Bermuda, Caribbean)

– Telson cleft with 14 laminae; distal margin of male pleopod 4 with 26–30 normal, non-flagellate spines ............................... H. (O.) bermudensis cesari Băcescu, 1968 (Gulf of Mexico, Caribbean)

36. Merus of thoracic endopod 3 with about 8 finger-like processes proximally on mesial margin......... ....................................................................................... H. digitata W.M. Tattersall, 1927 (Red Sea)

– Merus of thoracic endopod 3 without finger-like processes ............................................................ 37

37. Distal half of endopod of uropods without spines ........................................................................... 38

– Endopod of uropods with 14–15 spines reaching from proximal to at least part of distal half; male pleopod 4 modified by 7 small, flagellate spines; carpopropodus of thoracic endopod 3 with 3 flagellate spines.............................................................................. H. (O.) xanthops Ii, 1964 ( Japan)

38. Endopod of uropods without spine; pleopods without spines in both sexes ................................... 40

– Endopod of uropods with at least one spine .................................................................................... 39

39. Endopod of uropods with one spine ................................................................................................ 42

– Endopod of uropods with more than one spine ............................................................................... 46

40. Lateral margins of telson with 5 spines; telson cleft with 16–17 laminae; carpopropodus of thoracic endopod 3 with 3 flagellate spines ...................................................................................................... .......................................... H. dentata Hanamura & Kase, 2001 (E Indian Ocean: Christmas Island)

– Lateral margins of telson with> 6 spines; telson cleft with> 18 laminae ...................................... 41

41. Lateral margins of telson with 7–11 spines; telson cleft with 28–32 laminae..................................... ...................................................................................... H. dispar Brattegard, 1970 (Gulf of Mexico)

– Lateral margins of telson with 10–12 spines; telson cleft with 19–24 laminae .................................. ....................................................................................................... H. komaii Fukuoka, 2005 ( Japan)

42. Male pleopods 2–4 modified by flagellate spines, male pleopod 5 modified by about 11 short setae on apical to disto-mesial margin; all female pleopods without spines, with normal setae only; lateral margins of telson with 5–9 spines; telson cleft with about 22–31 laminae ..... H. (O.) kushimotensis Murano & Fukuoka, 2003 (Aquarium of the Kushimoto Marine Park Center, Japan)

– At least pleopod 5 unmodified in both sexes; lateral margins of telson with 6–10 spines .............. 43

43. Male pleopod 2 modified by flagellate spines; remaining male pleopods not modified; lateral margins of telson with 6 spines; telson cleft with 26 laminae .......................................................................... ........................... H. (O.) sixi sp. nov. (only 1 ♂ known) (tanks of the ‘Waikiki Aquarium’, Hawaii)

– Male pleopod 2 variously modified; male pleopod 3 modified by flagellate spines ...................... 44

44. Pleopod 2 with 5–6 minute flagellate spines in both sexes; male pleopods 3–4 with 2–7 and 11–12 flagellate spines, respectively; remaining pleopods without spines in both sexes; lateral margins of telson with 8–10 spines; telson cleft with 25–32 laminae .................................................................. ........................................... H. (O.) waikikensis sp. nov. (tanks of the ‘Waikiki Aquarium’, Hawaii)

– Male pleopod 2 variously modified but not with flagellate spines; male pleopod 3 with 13–22 flagellate spines; all female pleopods normal.................................................................................. 45

45. Male pleopod 2 tapering to form a seta-like apical process; male pleopod 3 with 15 flagellate spines; lateral margins of telson with 10 spines; telson cleft with about 30 laminae ...................................... ............................................................ H. (O.) meenakshiae Bamber, 2000 (W Pacific: Hong Kong)

– Male pleopods 1–2 ending in a large, smooth spine (stylet); male pleopod 3 with 13–22 flagellate spines; lateral margins of telson with 6–9 spines; telson cleft with about 14–22 laminae .............. 50

46. Pleopod 1 of both sexes with normal setae only.............................................................................. 51

– Male pleopod 1 modified ................................................................................................................. 47

47. Male pleopod 1 with 6 smooth, robust spines, pleopod 3 with 5–6 flagellate spines, pleopod 4 with dense series of 28–36 small blunt spines; male pleopods 2, 5, and all female pleopods without spines; telson cleft with 16–21 laminae............................................................................................... .......................... H. (O.) cocoensis Price , Heard & Vargas, 2018 (equatorial E Pacific: Coco Island)

– Male pleopod 1 ends in only one smooth spine or in attenuated setae............................................ 48

48. All pleopods non-dimorphic, with 14–29 modified attenuated setae in both sexes; rostrum triangular, apically broadly rounded, about half the length of terminal segment of antennular trunk; telson cleft with 12–15 laminae.......................................... H. (O.) mclellandi Price & Heard, 2011 (Caribbean)

– Male pleopods 1–2 ending in a long, smooth spine (stylet), male pleopods 3–4 modified by flagellate spines; male pleopod 5 and all female pleopods with normal setae only........................................ 49

49. Antennal scale and carpopropodus of thoracic endopod 3 subdivided; carpopropodus of thoracic endopod 3 with 6 flagellate spines....................................................................................................... H. (O.) smithsoniana sp. nov. (tanks of the ‘Smithsonian Marine Ecosystems Aquarium’, Florida)

– Antennal scale undivided; carpopropodus of thoracic endopod 3 undivided, with 3–5 flagellate spines ............................................................................................................................................... 50

50. Rostrum <¼ length of terminal segment of antennular trunk; male pleopods 3–4 with 15 and 18 flagellate spines, respectively; telson cleft with 20–22 laminae; endopod of uropods with 3–2 spines ............................................................................... H. (O.) gomezi Băcescu, 1970 (Caribbean)

– Rostrum> 4/5 length of terminal segment of antennular trunk; male pleopods 3–4 with 13–22 and 19–35 flagellate spines, respectively; telson cleft with 14–20 laminae; endopod of uropods with 1–4 spines ............................................... H. (O.) mayana Brattegard, 1970 (Caribbean, Gulf of Mexico)

51. Lateral margins of telson with 10–11 spines; rostrum about half as long as terminal segment of antennular trunk; male pleopods 3–4 with 6–10, and 8–15 flagellate spines, respectively; male pleopods 1–2, 5 and all female pleopods without spines; endopod of uropods with 4–5 spines ............................................................... H. (O.) rubrocincta Băcescu, 1968 (Gulf of Mexico)

– Lateral margins of telson with 4–9 spines; rostrum exceeds half the length of terminal segment of antennular trunk............................................................................................................................... 52

52. Male pleopod 3 with 7–8 large flagellate spines, pleopod 4 with 7–11 much smaller flagellate spines; male pleopods 1–2, 5, and all female pleopods not modified; rostrum 80–90% as long as terminal segment of antennular trunk; telson cleft with 15–22 laminae; endopod of uropods with 2–3 spines ................... H. (O.) sabelliphila Wittmann & Wirtz, 2017 (NE Atlantic: Cape Verde Islands)

– Male pleopod 2, and mostly also pleopods 3–4 modified; male pleopods 1, 5 and all female pleopods not modified; telson cleft with 21–27 laminae; endopod of uropods with 3–4 spines .................... 53

53. Antennular trunk with two forwardly directed, smooth setae on disto-mesial edge of terminal segment; no flagellate spine present. Apical cleft 22–23% telson length............................................ ........... H. tattersalli H. Nouvel, 1942 (only damaged ♂ known) (NE Atlantic: Cape Verde Islands)

– One strong, obliquely anteriorly directed, flagellate spine plus one large, smooth, antero-laterally directed seta on disto-mesial edge of terminal segment of antennular trunk. Apical cleft 24–29% telson length..................................................................................................................................... 54

54. Male pleopods 2–4 with 1–7, 0–4, and 0–4 flagellate spines, respectively; endopod of uropods with 3 spines; telson cleft with 21–23 laminae............................................................................................ ................................................................... H. (O.) dardani Wittmann, 2008 (NE Atlantic: Madeira)

– Male pleopods 2–4 with 9, 16–17, and 19 mostly flagellate spines, respectively; endopod of uropods with 4 spines; telson cleft with 24–27 laminae ................................................................................... ....................................................................... H. (O.) wirtzi Wittmann, 2008 (NE Atlantic: Madeira)