; Citation: Cole, G. A. 1988b. A report on the status of , including desperatus in New . Report submitted to the Endangered Program, New Mexico Department of Game and Fish under Professional Services Contract 519-77-02, Santa Fe, New Mexico.

ABSTRACT

Collections of New Mexican amphipod were made during the first week of May, 1988. In the Rio Honda, Lincoln Co., an adult female Gammarus and some immature specimens were found to be referable to G. lacustris Sars. Also, there were examples of that differed morphologically from those taken at the other collecting sites. North Spring at the Roswell Country Club, Chaves Co., was found to have been roofed-over and walled-up. There were amplexing Hyalella beneath debris in a shallow spring outflow, but no examples of Gammarus desperatus Cole could be found. It was impossible to collect in the depression where _§. desperatus once occurred. In the Bitter National Wildlife Refuge specimens of Hyalella were taken from a sinkhole and from a small section of lost . These were much like the Hyalella from Roswell. Also from lost River an oviger­ our female Gammarus and a larger male were taken. The latter had lost most of its antennular flagella , but it could be compared to _!h desperatus. and other members of the Gammarus-pecos complex. Careful comparisons of these two specimens with data derived from study of _!h desperatus and closely related forms imply that the lost River are related very closely to..§..:_ desperatus and may be conspecific with it, despite some vari­ ation. A REPORT SUBMITTED TO THE NEW MEXICO DEPARTMENT OF GAME AND FISH PROGRAM

Gerald A. Cole July 1988

On May 3, 1988, Gerald A. and Jean H. Cole began a collecting trip to New Mexico. The trip was planned to last three days leaving from Flagstaff, AZ., and travelling to the Bitter Lake National Wildlife Refuge With collecting stops along the way. On May 4 the search for amphipod crustaceans began at the Rio Hondo near Hondo, Lincoln County, NM. This site was just east of the junction of U. S. Route 70 and 380, off the main route where a silver-pa,inted iron bridge crosses the river below a small crudely built dam (Photos 1 and 2). In the grass and aquatic vegetation at the stream margins there occurred: snails, probably referable to Physa; amphipods referable to Hyalella and Gammarus. This collecting site will be referred to as Station A. At another place on the Rio Hondo, also in Lincoln Co., NM, more collections were made. This was about 4.9 miles east of Station A, on Route 70-380 east of Tinnie, NM, and the junction of State Route 368. Here a rusty metal bridge crosses the river. There was no nearby dam. Collecting done along the stream banks yielded some small specimens of Gammarus. This collecting site is designated Station B. In the afternoon of 4 May 1988 we reached the Roswell Country Club to look for Gammarus desperatus in North Spring. This site, in Chaves County, NM, is shown in Photos 3, 4, and 5; it is designated Station C. 2

We found that the spring had been roofed-over and sodded. A curved concrete wall, composed of four tiers of cinder blocks and topped in part by a layer of common building bricks, closed the downstream entrance to the spring except for a narrow space about 38 mm high between the lowest of the cinder blocks and a concrete apron that leads to a nearby golf-course pond. Water, 3-4 mm deep, flowed through the space from the walled-off and roofed-over spring. On the concrete apron were some cinder blocks, loose slabs of concrete, sticks and stones. Beneath there were many repre­ sentatives of Hyalella and some terrestrial isopods belonging to the genus Porcellio. Many of the Hyalella were paired in amplexus and some were gravid. However, no specimens of Gammarus were found at Station C. On May 5 we arrived at the Bitter Lake National Wildlife Refuge and were escorted by Lee Marlatt to two collecting sites in the Research Natural Area. The first of these, Station D, was a sinkhole (see Photos 6 and 7). David Galat, of Arizona State University's Department of Zoology, has studied several sinkholes in the Refuge and supplied me with some chemical data he determined on waters collected 30 March 1985. These are extremely saline waters. The mean total dissolved solids for water collected at about one meter's depth in six sinkholes was 39.06 grams per liter. The range was from 10.63 to 75.49 g/liter. Sodium and chloride are the princi­ pal ions, with sulfate being relatively more abundant in the lower salinities. AT the edge of the sinkhole five specimens of Hyalella and some small sinis­ trally coiled snails, probably members of Physa, were taken. The other collecting site in the Refuge was at a sharp bend in a small stream called Lost River. The edges of the stream were grassy and here were collected four specimens of Hyalella and seven individuals referable to Gammarus. This is Station E, and is portrayed in Photo 8. 3

Hyalella at Four Stations

The seven specimens of Hyalella collected at Station A along the

edges of the Rio Hondo have mouth parts that are considered typical of

Hyalella azteca (Saussure). This may be an inaccurate statement because: Saussure did not figure the mouth parts in his original description; the

species may be extremely variable; and there are probably many undescribed species masquerading as!!.:. azteca.

The endopod (or inner plate) of each first maxilla bears two terminal,

strong plumose setae. On the inner margin of the endopod of each maxilla 2 there are two stout plumose setae, proximal to the apex. The inner plate of each maxilliped bears three triangular apical teeth. Mouth parts such as those described above are not unique to H. azteca. The smooth-backed

Hyalella that occurs. in Montezuma Well, AZ, with H. montezuma has maxillae and maxillipeds similar to the Rio Hondo form. Also, some unpublished plates sent to me by Dr. E. L. 8ousfield show that two new species, Hyalella longicornis from a spring in St. George, UT, and.!!- caribbeana from Grand Terre, Guadeloupe, West Indies, show nearly identical mouth appendages.

The dorsal mucronation of H. azteca (that Saussure described from specimens collected in Vera Cruz, Mexico) consists of a mid-dorsal, daudally projecting spine on each of pleonites l and 2 (Saussure 1858, Plate V, Fig.

33). In the Rio Hondo specimens I found no freely projecting tergite spines. There was strong chitinization in the posterior midline of several segments, but they were what I shall call pseudospines; the outer, thin transparent cuticle covers them so they do not project freely. (A sketch is included to illustrate spines and pseudospines). In most specimens the last three pereonites bore short p,eudospines held closely to the dorsal surface. The first three pleonites bore longer,raised structures that looked like spines 4

unless examined under higher magnification. In addition, a very short depressed pseudospine was present on the first segment of the urosome. Superficial examination of the seven Rio Hondo specimens might result in one terming the pleonite segments spined. It may be that at other seasons the tergite spines would be free and the pleon dorsal sur­ face mucronate. There were, however, ovigerous females and mature males in the collection. At the Roswell Country Club (Station C) the thriving Hyalella popu­ lations living beneath debris on the concrete apron outside North Spring differ from the Rio Hondo forms. The inner plate of the first maxilla bears two terminal plumose setae with a similar sub-apical seta close to them; essentially there are three terminal setae on this structure. Features of maxilla 2 and the maxilliped, however, are comparable to the Station A forms. The dorsal mucronation of the North Spring animals involves the presence of well-defined caudally directed spines on pleonites 1 and 2. A pseudospine is present on the third pleonite, and a smaller one is present on the first uronite. In most specimens small pseudospines occur on the posterior pereonites, and in some specimens all seven pereonites appear to bear small depressed pseudospines. The Hyalella individuals from the sinkhole (Station D) in the Bitter Lake National Wildlife Refuge resembled those from Station C. They also showed the unusual feature of three plumose setae on the endopod of maxilla 1, one being slightly smaller and a bit sub-apical on the inner margin. Their mucronation was like that·of the North Spring amphipods although the pleonite spines of pleonite l and 2 seemed to be a little longer, and the pseudospine on pleonite 3 was almost "real". 5

Only four specimens of Hyalella were taken from Lost River (Station E).

The descriptions of the sinkhole population apply to the Lost River animals

with two exceptions: the tergite spines on pleonites 1 and 2 may have been shorter in the Lost River crustaceans; one of the individuals from Station

E had three stout plumose setae (rather than two) on the inner margin near the apex of the endopod of maxilla 2. The significance of this variation is not known.

Conclusions re Hyalella

There seem to be at least two discrete types of Hyalella described

above. The Rio Hondo population differs from animals in Roswell and those in the Bitter Lake Refuge. Throughout southwestern such

phenomena are collil1on; aquatic habitats are often island-like when compared

with waters in mesic regions. Much more speciation may have occurred than is generally acknowledged.

Few people have concentrated on the systematics of Hyalella in North America, and since the paper of Weckel (1907), more than eight decades ago, there has been a tendency to refer all populations to Hyalella azteca. Because Hyalella can be kept and raised easily in laboratory fingerbowls, it would be possible to test breeding success, fecundity, and degrees of reproductive isolation among populations. For example, the two forms living in Montezuma Well do not attempt interspecific amplexus when kept together in a fingerbowl. In addition, modern analytical methods such as starch-gel electrophoresis can be used to characterize Hyalella populations comparatively. Such studies probably would show that the aquatic fauna of

NewMexico is more diversified than we realize. 6

Gammarus Specimens

The collections at Stations A and 8 contained no mature males of Gammarus, but there was one large ovigerous female. It appears that this belongs to Gammarus lacustris Sars as we know it now. In the genus Gammarusmost descriptions are based on adult males, but some morphologic features of this female from Station A will be presented here.

The eye is small, its shape a short sub-reniform. There were 21 flagellar articles on antenna l (the antennule), and the accessory flagellum was composed of two segments. The ultimate, penultimate and antepenultimate peduncular segments bore 0, 2, and 2 clumps of ventral (posterior) groups of setae. Usually there are single groups of setae at these positions in amphipods assigned to_§_. lacustris. The proximal peduncular segment (ante­ penultimate) bore two setae and a spine at the posterodistal corner. This is an unusual feature for G. lacustris. The flagellum of antenna 2 was composed of 10 non-calceolate articles.

An adult male of G. lacustris would have been armed with calceoli here. The ultimate and penultimate peduncular segments of antenna 2 were subequal in length and each bore two tufts of posterior setae.

The mandibular palps bore no C-setae; the B-setae were in groups of two and five and were numerically superior to the A-setae. The A-setae were arranged in one group of five. There were seven alpha-setae set in a curved row with the intercalary setae 3 and 4 (going proximad) shorter than the adjacent alpha-setae 2 and 5. The mandibular palps are typical of G. lacustris. Coxal plates land 2 each bore two anterodistal setae, and one and two posterodistal setae, respectively. 7

Pereopods 6 and 7 bore no setae among the spinules arming segments 4 - 6 (merus, carpus and propodus); this is typical of.§_. lacustris. The expanded basis of pereopod 7 bore two clumps of anterior proximal setae, of four and eight each. There were four anterior spinules, each with an accompanying short seta. There were three spines and three setae at the anterodistal corner of the basis. The posterior margin was lined with nine short setae, the ultimate being the shortest. The underlying surface of the segment proper at the posterodistal corner of the basis plate supported two rather short setae. Thus, the features of the seventh

11 pereopod are much 1i ke the typica l II Q. 1acustri s.

The epimera do not differ significantly from those described pre­ viously for Gammaruslacustris. The posterodistal corners of epimeron 2 and epimeron 3 are slightly produced. Their anterior convexities are bare.

The urosome segments are not conspicuously humped dorsally. The sum of lateral and dorsal spinules born by the three uronites is 18. The third uropod has an endopod:exopod length ratio less than one, and the terminal segment of the exopod bears apical plumose setae. The structural features described in the above paragraphs fall well within the range of variation seen in G. lacustris and some (!·.9.· the man­ dibular palps) are considered to be diagnostic.

Gammaruslacustris is widespread in Europe and northern Asia. It may be the only freshwater species of the genus that crossed into North America, where it occurs in most of Alaska and Canada. The most southern populations are found locally in California, Nevada, Arizona and NewMexico.

It may have been the ancestor of Gammaruspseudolimnaeus, a North American form that seems closely related . .§_. troglophilus and.§_. bousfieldi, two narrowly distributed American species, also show relationships to G. lacustris. 8

It is quite possible that the New Mexican amphipods that we call G. lacustris in the Grants Lava Bed pools and the Rio Hondo have undergone differentiation from the original North American invader. There may be sib­ ling species involved that careful study will reveal. The Gammarus-lacustris complex on our continent deserves investigation by some dedicated student (s).

Lost River Gammarus

The Lost River collection (Station E) included only seven Gammarus individuals. Of these, five were small and obviously immature. There were two large specimens; one was a large male missing the flagella of its antennules; the other was an ovigerous female. These were 11 •• banded forms, with elongate reniform eyes, non-calceolate second antennae, C-setae on their mandibular palps and narrow oostegites". These quoted words (Cole 1985) describe members of the Gammarus-pecos complex of which_§.. desperatus is/was a member. The female had 34 setae on each of the first oostegites, falling within the range 28 - 35 reported for Q. desperatus by Cole (1981) in the original description of the species. Her antennules had 23 flagellar seg­ ments, suggesting that the larger, damaged male might have had 24 to 31 segments as reported in the paper that named the species. Cole (1985) compared 20 characters among seven populations of amphipods belonging to the _!h pecos complex. It is not possible to compare four of these characters in the single Lost River male because of the missing fla­ gella. The data for 16 other characters show this male to be very much like G. desperatus that once occurred in North Spring, Roswell, NM, only 12 - 15 miles (g. 19 - 24 km) away. The results are shown below, where 9

D represents~- desperatus. Six other populations were also coded with capital letters. The range of values is indicated in each instance, although all seven populations are not always shown. The relevant value derived from the lost River male is indicated with a number and arrow.

1. Antenna 1, peduncular segments, sum of posterior setae S, 6.3------D, 2.58f 2.5 2. Antenna 1, accessory flagellum, number of articles

P, 5.08------M, 4.67]E, 3.80 D, 3.70 H, 3.60

3. Antenna 2, flagellum/peduncle ratio of length

D, 0.896 j M, 0.869------S, 0.745 0.889 4. Antenna 2, peduncle, ultimate segment/penultimate segment, ratio of 1ength \C, 1.117------D, 1.004 1 .122 5. Antenna 2, peduncular segments, ultimate and penultimate,

sum of posterior setal tufts

P , 12 . 6 S, 10 . 8 f D, 7 . 6------h , 5 . 6 8.0 6. Antenna 2, number of f1age11ar articles P, 15.4------D, 13 t C, 13, H, 12 E, 11.0 13

7. Coxal plates, 1-4, antero-distal setation, sum of setae tD, 24.75------H, 10.40 26

8. Coxal plates, 1-4, posterior setation, sum of setae D, 16.92 f E, 11.86------H, 6.50 14 10

9. Coxal plates, 1-4, sum of anterior, posterior and facial setae D, 104.4 f E, 47 .D------H, 19.25 76

10. Pereopods, 1-4, bases, sum of anterior and posterior setae D, 192.2 t E, 127.4------H, 38.5 179 11. Pereopods 5, 6, 7, bases, proximal anterior setation, sum of setae

' D, 8.67------H, 4.0 29

12. Pereopods, 5, 6, 7, bases, anterior spinules, sum \ 0, 14.8------H, 7.5 19

13. Pereopods 5, 6, 7, bases, posterior margin, sum of setae D, 59.5 '\ P, 50.4------H, 21.25 56

14. Pereopods 5, 6, 7, bases, sum of anterior proximal setae, anterior spinules and posterior setae

" D, 83.0------H, 32.8 104

15. Uronites 1, 2, 3, sum of spinules, dorsals and both laterals t D, 19.8------M, 12 21 16. Uropod 3, endopod/exopod length ratio

S, D.846------C, 0.792 '\ E, 0.763 D, 0.683, H, 0.667 o. 778 11

These 16 comparisons reveal that the Lost River male Gammarus is very similar to D (§.. desperatus) in 13 or 14 instances. The average Gammarus desperatus male has more facial setae on the first four coxal plates, and its ultimate and penultimate peduncular segments (of antenna 1) may be more nearly equal in length than they are in the Lost River male. By contrast, the last three pairs of pereopods in the latter bear many more proximal anterior setae on the bases. Also, the Lost River male may have relatively longer endopods of the third uropod. In the original descrip­ tion of Q. desperatus (Cole, 1981) the endopod:exopod length ratio of uropod 3 was stated to range from 0.7 to 0.75. Further comparative descriptions of the male Gammarus from Station E are presented below, beginning with the anterior end. The antennules had two spines at the posterodistal corner of the first peduncular segment. The posterior surfaces of the antepenultimate, penultimate and ultimate peduncular segments of this appendage have 0-0, 1-2, and 1-1 setal tufts, respectively. (Both antennules were examined.) The spines on segment 1 are typical of the entire Gammarus-pecos complex; the posterior setal armament of the peduncle (0-2-1) is commonly found in Q. hyalelloides (from Jeff Davis County, TX; symbolized Hin the comparisons above), an unnamed species (the E population) from Eddy County, NM, and Ganvnarus desperatus. Sometimes the last species has a scanty tuft of pos­ terior setae on the first peduncular segment. The second antennae have been compared adequately for the Lost River male and Q. desperatus in comparisons 3, 4, 5, and 6. Except for the ratio of length shown for the ultimate and penultimate segment of the peduncle, the similarities are striking. 12

The mandibular palp of the Lost River male has many features shared by.§_. desperatus and others. The ultimate segment is distinctly shorter than the penultimate segment; this is typical of.§.. desperatus, the Eddy

County form, and.§.. hyalelloides. The C-setae are shorter than those of

.§_. desperatus, just attaining or barely surpassing the D-spines. There is, however, one pair of C-setae that seem to be a couplet, reminiscent of G.

desperatus and the E population from Eddy Co., NM. The A-setae are longer than the B-setae and reach slightly past the distal tip of the segment, a feature sometimes seen in Q. desperatus. The alpha-setae are subequal to, or slightly longer than the E-setae, a feature of§_. desperatus, although

not unique to it in the.§_. pecos group. Some aspects of the coxal plates and pereopods have been treated in the comparative tests. It should be pointed out, however, that the posterior margins of the bases of pereopods 5, 6, and 7 are straight to concave. This is a character seen in.§_. desper­ atus, but not in the two other described species of the.§.. pecos complex

(.§.. pecos and.§.. hyalelloides). The ischia of pereopods 5, 6 and 7 in the Lost River male have bare anterior and posterior surfaces. Of the Q. desperatus specimens I have examined, some bear spinules or setae on these surfaces. Inexplicably, others have unadorned ischia. The extent of this variation has not been studied.

To present comparison of the pleopods, a table is inserted here. The mean numbers for G. desperatus examined (see Cole, 1981) are typed above those derived from examination of the Lost River male. 13

Pleopod 1 Pleopod 2 Pl eopod 3

Exopod, segments 18 17 16 22 19 18

Exopod, setae on fused basal segments 9 8 7 8 6 5

Endopod, segments 15 14 14 19 17 15 Endopod, fused basal segments, split-tipped setae and proximal 6 & 1 5 & 1 4 & 1 plumose setae, numbers respectively 4 & 1 4 & 1 3 & 1 Protopod, curved nodose coupling hooks and setae, 2 & 2-3 2 & 2-3 2 & 2-3 numbers respectively 2 & 4 2- & 2 2 & 3

Some other comparisons of the Lost River male with the wording in the original description of G. desperatus are outlined below.

G. desperatus Lost River Male

Uropod 1 longer than uropod 2, longer than uropod 2, protopod 0.6 x total length, protopod 0.57 x total length, rami subequa1 endopod 1.019 x exopod

Uropod 2 endopod 1.3 x exopod length, endopod 1.22 x exopod length, protopod 0.5 x total length protopod 0.5 x total length

Uropod 3 endopod: exopod length ratio endopod:exopod 0.77 0.70 - D.75 14

The tiny terminal segment of the third uropod exopod in the Lost

River male bears no lateral insertions and five or six smooth apical

setae; the same can be said for Gammarusdesperatus. In Gammaruspecos this terminal segment has ·~.. up to nine terminal setae of two types and

rarely a spine, rarely l or 2 setae inserted on the inner margin. 11 (Cole

and Bousfield, 1970). In Gammarus hyalelloides, :!--"terminal segment

with four apical setae, no laterally inserted setae. 11 (Cole, 1976). rn· the same paper, Figure 1-d shows the apical setae to be all plumose. The

population M, from "Spring 3.5 miles west of Toyahvale, Reeves Co., "

{Cole 1985, p. 95) has a third uropod like§.. hyalelloides and may be the

same species. The larger, undescribed species C, co-occurring with§.. hyalelloides in waters derived from Phantom Lake Spring, has the terminal

segment of the third uropod's exopod armed like thbse of G. pecos. The

same may be said for population S from San Solomon Springs• outflow, Reeves

Co., Texas; this population may be referable to G. pecos. The Eddy County form (E) is closely related to_§_. desperatus, and also has the terminal segment of the third uropod's exopod armed like the latter species and the Lost River male. The preceding paragraph compares uropod 3 (in part) with all the

known populations of the Gammarus-pecos complex. Details of its armament may be more important in showing relationships than has been believed. It is another piece in a pattern that suggests the population of gammarids in

Lost River is closely related to Gammarusdesperatus, probably no longer existing in North Spring, Roswell, NM. Another feature of the Lost River gammarids is something one would not find in Gammarus lacustris. The so-called coxal gill of pereopod 7 1S arises at the junction of the coxa and basis, very close to rising from the latter. This is an unusual character that is typical of the §..-pecos complex. In conclusion, it is quite possible that Gammarusdesperatus still exists in at least the Lost River within the Bitter Lake National Wildlife

Refuge. An alternative possibility is that a closely-related sibling species lives there -- a species that has more morphologic similarities to

Q. desperatus than any other known member of the Mexican(?), Texan, New

Mexican Gammarus-pecos complex. It may never be possible to ascertain whether Lost River and North Spring populations are/were reproductively isolated, but there are exciting possibilities for further exploration and study. Good luck, someone!!

Literature Cited

Cole, G. A. 1976. A new amphipod , Gammarus hyalelloides n. sp., from Texas. Trans. Amer. Micros. Soc. 95(1): 80-85.

1981. Gammarusdesperatus, a new species from NewMexico (Crustacea: Amphipoda). Hydrobiologia 76: 27-32. 1985. Analysis of the Gammarus-pecos complex (Crustacea:Amphipoda)

in Texas and NewMexico, USA. Jour. Arizona-Nevada Acad. Sci. 20(2): 93-1D3.

&E. L. Bousfield. 197D. A new freshwater Gammarus (Crustacea:Am­ phipoda) from western Texas. Amer. Midl. Nat. 83(1): 89-95.

Saussure, H. 1858. Memoire sur divers crustaces nouveaux des Antilles et

du Mexique. Mem. Soc. Physique Hist. Nat. Geneve. 14: 417-496. 6 pl.

Weckel, A. L. 1907. The fresh-water Amphipoda of North America. Proc. U.S. Nat. Mus. 32: 25-58. Acknowledgements

I am indebted to several people for making this report possible. Lee

B. Marlatt was kind enough tb take us into a restricted area of the Bitter

Lake Wildlife Refuge, where the important discovery of Gammarusspecimens was made. Peggy Pollak was instrumental in preparing laboratory space and acquiring microscopes for my use, and David J. Pryor kindly gave his appro­ val and loaned me keys so I could work in the Biological Sciences building at Northern Arizona University. Finally, I acknowledge my indebtedness to my wife Jean, who helped with preparing for the trip, driving, cooking at campsites, to say nothing of editing and typing the manuscript.

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